搜索[鸿蒙实践]结果-低调大师优秀个人博客

精选列表

搜索[鸿蒙实践]，共10000篇文章

PostgreSQL jsonpath使用实践

jsonpath是用来解析json数据的工具，类似于xpath，jsonpath可以解析十分复杂的json数据。 PostgreSQL json发展历史： PostgreSQL从9.2开始就支持json数据类型，但是由于解析json数据的性能很差，导致并不受大家青睐，而是选择使用nosql数据库代替。于是从pg9.4开始支持了jsonb数据类型，相较于json类型，jsonb由于并不需要每次使用时都去进行解析，因此性能提升很多，都是还支持索引查询等。而从pg12开始对于json的支持更加强大：sql 2016的sql/json标准有15条， PG 12 实现了14条，远远超过oracle(18c 11/15), mysql(8.0.4 5/15), sqlserver(2017 2/15)最新版本。同时在pg12中引入了jsonpath类型，以及一系列相关的函数，使得json数据的查询性能更进一步，功能也愈发强大。 JSONPATH语法： JSONpath 函数表达式语法如下：点号 . 表示引用 Json 数据的元素方括号 [] 表示引用数组元素 Json 数据中的数组元素下标从0开始 JSONpath中的变量如下： $ 符号表示要查询的Json文本的变量 $varname 表示指定变量 @ 指在 filter 表达式中表示当前路径元素的变量 JSONPATH使用举例：简单查询： bill@bill=>SELECT jsonb_path_query_array('[1,2,3,4,5]', '$[*] ? (@ > 3)'); jsonb_path_query_array ------------------------ [4, 5] (1 row) 创建测试表： CREATE TABLE house(js jsonb); INSERT INTO house VALUES ('{ 'address': { 'city':'Moscow', 'street': 'Ulyanova, 7A' }, 'lift': false, 'floor': [ { 'level': 1, 'apt': [ {'no': 1, 'area': 40, 'rooms': 1}, {'no': 2, 'area': 80, 'rooms': 3}, {'no': 3, 'area': 50, 'rooms': 2} ] }, { 'level': 2, 'apt': [ {'no': 4, 'area': 100, 'rooms': 3}, {'no': 5, 'area': 60, 'rooms': 2} ] } ] }'); 查询： bill@bill=>select jsonb_pretty(js) from house ; jsonb_pretty ---------------------------------- { + 'lift': false, + 'floor': [ + { + 'apt': [ + { + 'no': 1, + 'area': 40, + 'rooms': 1 + }, + { + 'no': 2, + 'area': 80, + 'rooms': 3 + }, + { + 'no': 3, + 'area': 50, + 'rooms': 2 + } + ], + 'level': 1 + }, + { + 'apt': [ + { + 'no': 4, + 'area': 100,+ 'rooms': 3 + }, + { + 'no': 5, + 'area': 60, + 'rooms': 2 + } + ], + 'level': 2 + } + ], + 'address': { + 'city': 'Moscow', + 'street': 'Ulyanova, 7A'+ } + } (1 row) 该数据的层次结构如下图：看上去该数据层次挺复杂的，但是实际中可能数据层次远比这个复杂的多，那么我们看看如何使用jsonpath来进行查询的： bill@bill=>SELECT jsonb_path_query_array(js, '$.floor[0, 1].apt[1 to last]') FROM house; jsonb_path_query_array ----------------------------------------------------------------------------------------------------------- [{'no': 2, 'area': 80, 'rooms': 3}, {'no': 3, 'area': 50, 'rooms': 2}, {'no': 5, 'area': 60, 'rooms': 2}] (1 row) 而如果不用jsonpath的话，我们可能需要这么写： bill@bill=>SELECT jsonb_agg(apt) FROM ( bill(# SELECT apt->generate_series(1, jsonb_array_length(apt) - 1) FROM ( bill(# SELECT js->'floor'->unnest(array[0, 1])->'apt' FROM house bill(# ) apts(apt) bill(# ) apts(apt); jsonb_agg ----------------------------------------------------------------------------------------------------------- [{'no': 2, 'area': 80, 'rooms': 3}, {'no': 3, 'area': 50, 'rooms': 2}, {'no': 5, 'area': 60, 'rooms': 2}] (1 row) 相比之下，使用jsonpath相关的函数查询简便太多了。又比如，我们需要判断json数据中是否包含某个值，可以这样： bill@bill=>SELECT jsonb_path_exists(js, '$.** ? (@ == 'Moscow')') FROM house; jsonb_path_exists ------------------- t (1 row) 而如果不使用jsonpath呢？ bill@bill=>WITH RECURSIVE t(value) AS ( bill(# SELECT * FROM house UNION ALL ( bill(# SELECT COALESCE(kv.value, e.value) AS value bill(# FROM t bill(# LEFT JOIN LATERAL jsonb_each ( bill(# CASE WHEN jsonb_typeof(t.value) = 'object' THEN t.value bill(# ELSE NULL END bill(# ) kv ON true bill(# LEFT JOIN LATERAL jsonb_array_elements ( bill(# CASE WHEN jsonb_typeof(t.value) = 'array' THEN t.value bill(# ELSE NULL END bill(# ) e ON true bill(# WHERE kv.value IS NOT NULL OR e.value IS NOT NULL bill(# ) bill(# ) SELECT EXISTS (SELECT 1 FROM t WHERE value = ''Moscow''); exists -------- t (1 row) 那么如何使用jsonpath进行数据过滤呢？已上面这张表为例，我们查询apt.no大于3的数据： bill@bill=>SELECT jsonb_path_query(js, '$.floor.apt.no ? (@>3)') FROM house; jsonb_path_query ------------------ 4 5 (2 rows) 同样，jsonpath也支持索引的使用： bill@bill=>CREATE INDEX ON house USING gin (js); CREATE INDEX bill@bill=>SET ENABLE_SEQSCAN TO OFF; SET bill@bill=>EXPLAIN (COSTS OFF) SELECT * FROM house bill-# WHERE js @? '$.floor[*].apt[*] ? (@.rooms == 3)'; QUERY PLAN -------------------------------------------------------------------------------- Bitmap Heap Scan on house Recheck Cond: (js @? '$.'floor'[*].'apt'[*]?(@.'rooms' == 3)'::jsonpath) -> Bitmap Index Scan on house_js_idx Index Cond: (js @? '$.'floor'[*].'apt'[*]?(@.'rooms' == 3)'::jsonpath) (4 rows) 除此之外，jsonpath支持了20多种相关的函数，是不是十分强大，赶快用起来吧！ postgres=# \df *.*json*path* List of functions Schema | Name | Result data type | Argument data types | Type ------------+------------------------------+------------------+------------------------------------------------------------------------------------------ -+------ pg_catalog | gin_consistent_jsonb_path | boolean | internal, smallint, jsonb, integer, internal, internal, internal, internal | func pg_catalog | gin_extract_jsonb_path | internal | jsonb, internal, internal | func pg_catalog | gin_extract_jsonb_query_path | internal | jsonb, internal, smallint, internal, internal, internal, internal | func pg_catalog | gin_triconsistent_jsonb_path | 'char' | internal, smallint, jsonb, integer, internal, internal, internal | func pg_catalog | json_extract_path | json | from_json json, VARIADIC path_elems text[] | func pg_catalog | json_extract_path_text | text | from_json json, VARIADIC path_elems text[] | func pg_catalog | jsonb_delete_path | jsonb | jsonb, text[] | func pg_catalog | jsonb_extract_path | jsonb | from_json jsonb, VARIADIC path_elems text[] | func pg_catalog | jsonb_extract_path_text | text | from_json jsonb, VARIADIC path_elems text[] | func pg_catalog | jsonb_path_exists | boolean | target jsonb, path jsonpath, vars jsonb DEFAULT '{}'::jsonb, silent boolean DEFAULT false | func pg_catalog | jsonb_path_exists_opr | boolean | jsonb, jsonpath | func pg_catalog | jsonb_path_exists_tz | boolean | target jsonb, path jsonpath, vars jsonb DEFAULT '{}'::jsonb, silent boolean DEFAULT false | func pg_catalog | jsonb_path_match | boolean | target jsonb, path jsonpath, vars jsonb DEFAULT '{}'::jsonb, silent boolean DEFAULT false | func pg_catalog | jsonb_path_match_opr | boolean | jsonb, jsonpath | func pg_catalog | jsonb_path_match_tz | boolean | target jsonb, path jsonpath, vars jsonb DEFAULT '{}'::jsonb, silent boolean DEFAULT false | func pg_catalog | jsonb_path_query | SETOF jsonb | target jsonb, path jsonpath, vars jsonb DEFAULT '{}'::jsonb, silent boolean DEFAULT false | func pg_catalog | jsonb_path_query_array | jsonb | target jsonb, path jsonpath, vars jsonb DEFAULT '{}'::jsonb, silent boolean DEFAULT false | func pg_catalog | jsonb_path_query_array_tz | jsonb | target jsonb, path jsonpath, vars jsonb DEFAULT '{}'::jsonb, silent boolean DEFAULT false | func pg_catalog | jsonb_path_query_first | jsonb | target jsonb, path jsonpath, vars jsonb DEFAULT '{}'::jsonb, silent boolean DEFAULT false | func pg_catalog | jsonb_path_query_first_tz | jsonb | target jsonb, path jsonpath, vars jsonb DEFAULT '{}'::jsonb, silent boolean DEFAULT false | func pg_catalog | jsonb_path_query_tz | SETOF jsonb | target jsonb, path jsonpath, vars jsonb DEFAULT '{}'::jsonb, silent boolean DEFAULT false | func pg_catalog | jsonpath_in | jsonpath | cstring | func pg_catalog | jsonpath_out | cstring | jsonpath | func pg_catalog | jsonpath_recv | jsonpath | internal | func pg_catalog | jsonpath_send | bytea | jsonpath | func (25 rows) 参考链接： https://github.com/digoal/blog/blob/master/202010/20201013_01.md http://www.postgres.cn/docs/12/functions-json.html http://www.postgres.cn/docs/12/datatype-json.html#DATATYPE-JSONPATH

2021-06-16

Golang 并发编程实践

Go 实现最简单的并发 for i := 0; i < 10; i++ { go func(n int) { fmt.Println(n) }(i) } 项目实践最近有个项目需要同时调用多个

2021-03-27

DHCP最佳实践（一）

这是Windows DHCP最佳实践和技巧的最终指南。如果您有任何最佳做法或技巧，请在下面的评论中发布它们。在本指南（一）中，我将分享以下DHCP最佳实践和技巧。

2021-01-17

Terraform应用最佳实践

阿里云最佳实践频道：【点击查看更多上云最佳实践】这里有丰富的企业上云最佳实践，从典型场景入门，提供一系列项目实践方案，降低企业上云门槛的同时满足您的需求！

2020-09-17

Code Review最佳实践

我一直认为Code Review(代码审查)是软件开发中的最佳实践之一，可以有效提高整体代码质量，及时发现代码中可能存在的问题。

2020-09-04

Flink State 最佳实践

本文主要分享与交流 Flink 状态使用过程中的一些经验与心得，当然标题取了“最佳实践”之名，希望文章内容能给读者带去一些干货。

2020-04-22

深度学习最佳实践

最佳实践，顾名思义，就是做某事的最佳方法，当然，这里的最佳一定是绝大多数情况，但又不是百分百的情况，我们不必纠结这个问题，我们需要记住的是下面这些方法在深度学习实践中是非常好的做法。

2020-03-23

Deeplink实践原理分析

目录介绍 01.先看一个场景 02.什么是DeepLink 03.什么是Deferred DeepLink 04.什么是AppLink 05.DeepLink和AppLink核心技术 06.DeepLink实践方案

2019-12-08

标签的最佳实践

使用场景：资源溯源标签标签管理应用发布流程使用标签分组自动化运维成本管理标签（资源费用分账）基于标签设计资源的访问控制最佳实践在为资源创建标签标记策略时，确保它准确地标识在相关的维度上并遵循以下最佳实践

2019-08-19

spring cloud gateway实践

一、前言 gateway是spring cloud全家桶的一员，主要用作微服务的网关，是spring官方基于spring5.0，spring boot 2.0和project reactor等技术开发的网关服务，旨在为微服务提供一种简单有效的统一api路由管理方式，基于filter链的方式提供了网关的基本功能如安全、监控、埋点、限流等。项目地址：https://spring.io/projects/spring-cloud-gateway 二、使用 1、依赖 spring cloud已集成gateway，只需要引入spring cloud的父pom，就能直接使用。 <dependencyManagement> <dependencies> <

2019-03-25

FaaS 的简单实践

可以考虑使用 Firehose 作为从物联网到 S3/reshift 和 EMR 集群的传输流来进行数据处理，但对于这个简单实践而言，这里只是一个临时的做法。

2018-12-16

React Native 分包实践

1. 实现思路 1. RN从本地中读取bundle文件进行显示 2. 将JS文件进行分包打包 3. Native实现页面跳转，每个包跳转都为一个新的Activity 4. 进行bundle文件基础包与功能包的拆分，使用Google的diff_match_patch算法生成差异文件 5. 网络下载差异文件进行合并 6. 展示新页面 2. 操作步骤 Android 1. 修改MainApplication 2. 修改MainActivity 3. 创建LocalReactActivityDelegate 4. 打第一bundle react-native bundle --platform android --dev false --entry-file index.js --bundle-output bundle/index.android.bundle --assets-dest bundle/assets/ 5. 打第二个bundle react-native bundle --platform android --dev false --entry-file src/indexNet.js --bundle-output bundle/index1.android.bundle --assets-dest bundle/assets/ 其中indexNet.js是新页面的入口文件 6. 使用google-diff-match-patch进行差异比对 3. 本地加载实现 1). 修改MainApplication public class MainApplication extends Application { private static MainApplication sInstance; /** * 获取当前对象 */ public static MainApplication getInstance() { return sInstance; } @Override public void onCreate() { super.onCreate(); sInstance = this; SoLoader.init(this, /* native exopackage */ false); } } 这里主要是将Application中实现的接口取消，转由MainActivity中提供. 2). 修改MainActivity public class MainActivity extends ReactActivity { /** * Returns the name of the main component registered from JavaScript. * This is used to schedule rendering of the component. */ @Override protected String getMainComponentName() { return "Unpacking"; } @Override protected ReactActivityDelegate createReactActivityDelegate() { return new LocalReactActivityDelegate(this, getMainComponentName()); } } 这里实现ReactActivity中的createReactActivityDelegate方法，自定义代理设置 3). LocalReactActivityDelegate代理代码 /** * 本地ReactActivity代理 */ class LocalReactActivityDelegate(activity: Activity, @Nullable mainComponentName: String) : ReactActivityDelegate(activity, mainComponentName) { private val mReactNativeHost: ReactNativeHost = object : ReactNativeHost(MainApplication.getInstance()) { /** * 返回ReactPackage对象 */ override fun getPackages(): MutableList<ReactPackage> = Arrays.asList( MainReactPackage(), CustomPackage() ) /** * 是否为开发 */ override fun getUseDeveloperSupport(): Boolean = BuildConfig.DEBUG /** * 返回JSBundle文件路径 */ override fun getJSBundleFile(): String? = "${Environment.getExternalStorageDirectory()}/bundle/index.android.bundle" } /** * 返回ReactNativeHost对象 */ override fun getReactNativeHost(): ReactNativeHost = mReactNativeHost } 4). Native实现页面跳转 I. 创建CustomPackage /** * 自定义ReactPackage */ class CustomPackage : ReactPackage { /** * 创建本地模块 */ override fun createNativeModules(reactContext: ReactApplicationContext?): MutableList<NativeModule> = Arrays.asList(PageModule(reactContext)) /** * 创建视图管理者 */ override fun createViewManagers(reactContext: ReactApplicationContext?): MutableList<ViewManager<View, ReactShadowNode<*>>> = Collections.emptyList() } 5). 创建PageMoudle /** * 页面管理模块 */ @ReactModule(name = "PageModule") class PageModule(reactContext: ReactApplicationContext?) : ReactContextBaseJavaModule(reactContext) { override fun getName(): String = "PageModule" /** * 开启网络上的模块页面 */ @ReactMethod fun startNetActivity() { val intent = Intent(currentActivity, NetActivity::class.java) currentActivity?.startActivity(intent) } } 6). NetActivity页面 /** * 新页面 */ class NetActivity : ReactActivity() { override fun getMainComponentName(): String? { return "NetActivity" } override fun createReactActivityDelegate(): ReactActivityDelegate = object: ReactActivityDelegate(this, mainComponentName) { override fun getReactNativeHost(): ReactNativeHost = object : ReactNativeHost(MainApplication.getInstance()) { override fun getPackages(): MutableList<ReactPackage> = Arrays.asList(MainReactPackage()) override fun getUseDeveloperSupport(): Boolean = BuildConfig.DEBUG override fun getJSBundleFile(): String? = "${Environment.getExternalStorageDirectory()}/bundle/index1.android.bundle" } } } 7). RN中使用修改App.js文件 /** * Sample React Native App * https://github.com/facebook/react-native * * @format * @flow */ import React, {Component} from 'react'; import {Platform, StyleSheet, Text, View, NativeModules, TouchableOpacity} from 'react-native'; const PageModule = NativeModules.PageModule; const instructions = Platform.select({ ios: 'Press Cmd+R to reload,\n' + 'Cmd+D or shake for dev menu', android: 'Double tap R on your keyboard to reload,\n' + 'Shake or press menu button for dev menu', }); type Props = {}; export default class App extends Component<Props> { startPage() { PageModule.startNetActivity() } render() { return ( <View style={styles.container}> <Text style={styles.welcome}>Welcome to React Native!</Text> <Text style={styles.instructions}>To get started, edit App.js</Text> <Text style={styles.instructions}>{instructions}</Text> <TouchableOpacity onPress={() => this.startPage()} > <Text style={styles.instructions}>开启新页面</Text> </TouchableOpacity> </View> ); } } const styles = StyleSheet.create({ container: { flex: 1, justifyContent: 'center', alignItems: 'center', backgroundColor: '#F5FCFF', }, welcome: { fontSize: 20, textAlign: 'center', margin: 10, }, instructions: { textAlign: 'center', color: '#333333', marginBottom: 5, }, }); 8). 执行打包 react-native bundle --platform android --dev false --entry-file index.js --bundle-output bundle/index.android.bundle --assets-dest bundle/assets/ --platform: 平台 --dev: 是否为开发模式 --entry-file: 入口文件 --bundle-output: bundle输出路径，这里注意bundle文件夹必须存在 --assets-dest: 资源文件存放路径 9). 测试 I. 生成之后将bundle文件夹拷贝至sdcard下 II. 如果想要在调试时可用，务必修改android/app/build.gradle文件,将bundleInDebug设置为false, 设置为false之后即不将bundle文件打包进app project.ext.react = [ entryFile : "index.js", bundleInDebug: false ] III. 运行注：此时无法开启新的页面，因为新页面的js文件不存在 4. 开启新页面 1). RN中创建入口文件indexNet.js /** @format */ import {AppRegistry} from 'react-native'; import NetJs from './NetJs'; import {name as appName} from './NetActivity'; AppRegistry.registerComponent(appName, () => NetJs); 2). RN中创建NetActivity.json文件 { "name": "NetActivity", "displayName": "NetActivity" } 注：此处的name和displayName应当与NetActivity.kt中的getMainComponentName方法返回的一致。 3). NetJs.js文件内容 import React, {PureComponent} from 'react'; import { StyleSheet, Text, View } from 'react-native'; /** * @FileName: NetJs * @Author: mazaiting * @Date: 2018/10/9 * @Description: */ class NetJs extends PureComponent { render() { return ( <View style={styles.container}> <Text>Welcome mazaiting!</Text> </View> ) } } /** * 样式属性 */ const styles = StyleSheet.create({ container: { backgroundColor: '#DDD' } }); /** * 导出当前Module */ module.exports = NetJs; 4). 打包 react-native bundle --platform android --dev false --entry-file src/indexNet.js --bundle-output bundle/index1.android.bundle --assets-dest bundle/assets/ 5). 拷贝文件将bundle文件夹直接拷贝到sdcard目录下，此时再重新运行APP, 即可成功显示页面。 6). 带来的问题初始包太大，每个包都讲RN基础内容打包，此时应该比较差异，进行差异化分解。 5. 差异化 1). diff-match-patch主页 2). 测试页面 3). 依赖 implementation 'google-diff-match-patch:google-diff-match-patch:0.1' 4). 代码使用 const val FILE1 = "index.android" const val FILE2 = "index1.android" const val FILE3 = "$FILE2-$FILE1.patch" const val FILE_DIR = "E:\\android\\React-Native-Study\\Unpacking\\bundle\\" const val SUFFIX = ".bundle" object Patch { @JvmStatic fun main(args: Array<String>) { val file1 = "$FILE_DIR$FILE1$SUFFIX" val file2 = "$FILE_DIR$FILE2$SUFFIX" val file3 = "$FILE_DIR$FILE3" val patch = productPatch(file1, file2) productFile(file1, file3, patch) } /** * 生成文件 * @param fileOri 源文件 * @param fileDest 目标文件 * @param patchString 差异字符串 */ private fun productFile(fileOri: String, fileDest: String, patchString: String?) { // 创建对象 val patch = diff_match_patch() // 读取文件 val file1 = readFile(fileOri) // 获取补丁内容 val patchText = patch.patch_fromText(patchString) // 应用补丁 val patchApply = patch.patch_apply(LinkedList(patchText), file1) println("===============================================") println("结果：" + patchApply[0]) // 写入文件内容 writeResult(fileDest, patchApply[0].toString()) println("===============================================") // 获取执行结果数组，true为成功，false为失败 val patchResult: BooleanArray = patchApply[1] as BooleanArray val result = StringBuilder() patchResult.forEach { result.append("$it ") } println("result: $result") } /** * 写入文件 * @param fileDest 目标文件 * @param string 文件内容 */ private fun writeResult(fileDest: String, string: String) { // Read a file from disk and return the text contents. val output = FileWriter(fileDest) val writer = BufferedWriter(output) try { writer.write(string) } finally { writer.close() output.close() } } /** * 生成差异patch * @param fileOri 源文件 * @param fileDest 目标文件 * @return 差异字符串 */ private fun productPatch(fileOri: String, fileDest: String): String? { // 创建对象 val diff = diff_match_patch() // 读取基础文件内容 val file1 = readFile(fileOri) // 读取目标文件内容 val file2 = readFile(fileDest) // 进行差异化 val diffString = diff.diff_main(file1, file2, true) // 数组长度大于2执行 if (diffString.size > 2) { diff.diff_cleanupSemantic(diffString) } println(diffString) println("===============================================") // 生成patch内容 val patchString = diff.patch_make(file1, diffString) println(patchString) println("===============================================") // 将patch内容转为字符串 val patchText = diff.patch_toText(patchString) println(patchText) return patchText } /** * 读取文件 * @param filename 文件名 * @return 文件内容 */ @Throws(IOException::class) private fun readFile(filename: String): String { // Read a file from disk and return the text contents. val sb = StringBuilder() val input = FileReader(filename) val bufRead = BufferedReader(input) try { var line = bufRead.readLine() while (line != null) { sb.append(line).append('\n') line = bufRead.readLine() } } finally { bufRead.close() input.close() } return sb.toString() } } 6. [代码下载] (https://gitee.com/mazaiting/React-Native-Study/tree/master/Unpacking)

2018-10-09

Go HttpServer 最佳实践

这是 Cloudflare 的 Filippo Valsorda 2006年发表在Gopher Academy的一篇文章，虽然过去两年了，但是依然很有意义。先前 crypto/tls 太慢而net/http也很年轻，所以对于Go web server来说，通常我们明智的做法把它放在反向代理的后面，如nginx等，现在不需要了。在Cloudflare我们最近试验了直接暴漏纯Go的服务作为主机。 Go 1.8的net/http 和 crypto/tls 提供了稳定的、高性能并且灵活的功能。然后，需要做一些调优的工作，本文我们将展示怎么去调优和使web服务器更稳定。 crypto/tls 2016年了，你不会再运行一个不加密的HTTP Server，所以你需要crypto/tls。好消息使这个库已经非常快了(我们的测试)，目前他的安

2018-07-29

EdgeX Foundry 实践篇

概述 2017年4 月份， Linux 基金组织启动开源项目 EdgeX Foundry ，为物联网边缘计算开发一个标准化互操作框架。 EdgeX Foundry 项目构建于戴尔早期基于 Apache2.0 协议的 FUSE 物联网中间件框架，无关操作系统和硬件的边缘框架。 EdgeX Foundry 旨在创造一个互操作性、即插即用、模块化的物联网边缘计算的生态系统。总体架构部署环境要求内存: 不小于4 GB 硬盘空间: 大于3 GB OS: Windows (ver 7 - 10) Ubuntu Desktop (ver 14-16) Ubuntu Server (ver 14) Ubuntu Core (ver 16) Mac OS X 10 User 模式安装Docker Mac 在安装Docker时自动安装Docker Composehttps://docs.docker.com/engine/getstarted/https://docs.docker.com/compose/install/ 下载EdgeX compose 文件官方文档有问题，https://github.com/edgexfoundry/developer-scripts/blob/master/compose-files/docker-compose.yml，部分模块无法下载与Jeremy Phelps 沟通，确认该文件存在问题，模块版本变化较多解决方案使用https://github.com/edgexfoundry/developer-scripts/blob/master/compose-files/docker-compose-california-0.5.2.yml，支持最新版本部分模块需要权限，需要登入docker，docker login nexus3.edgexfoundry.org:10004 -u docker -p docker 运行EdgeX 拉取镜像启动volume镜像启动configuration/registry 微服务启动mongo 启动logging微服务启动notifications微服务启动Metadata微服务启动scheduling微服务启动virtual device s微服务同理启动其他微服务检查微服务都启动完毕微服务端口镜像位置 Developers模式准备工作 Githttps://git-scm.com/downloads Mongodbhttps://www.mongodb.com/download-center?jmp=nav#community Javahttp://www.oracle.com/technetwork/java/javase/downloads/index.html Eclipsehttp://www.eclipse.org/downloads/eclipse-packages EdgeX github地址https://github.com/edgexfoundry 模块依赖关系安装启动Mongo Database 初始化数据库启动微服务 Google IoT Core实战待补充

2018-07-08

直播转点播实践

场景简介直播转点播（直转点）是将直播流同步录制为点播视频，并支持媒资管理、媒体处理（转码及内容审核/智能首图等AI处理）、内容制作（云剪辑）、CDN分发加速等一系列操作，可配置工作流自动处理，也可通过API/SDK灵活触发。准备工作开通视频点播服务，开通指引开通视频直播服务，开通指引添加直转点录制配置，帮助文档上述准备工作完成后，即可开始进行接入(注：下述文档中的仅存储、仅合成模板组需联系点播进行激活) 名词解释直转点，结合视频点播的转码、云剪辑、AI处理、事件通知等功能，可适应多种业务场景。名词解释：录制转码模板组：直播录制到点播同时，点播会使用该模板组对视频进行转码操作合成转码模板组：多个录制视频进行自动合成时，点播会使用该模板组对视频进行合成+转码操作仅存储：对直播内容进行录制后，不进行任何后续操作仅合成：对直播内容进行合成后

2018-06-10

Android 快应用实践

1. 应用配置信息 1). package.json name: 项目名称 version: 版本信息 toolkit: hap 版本 description: 描述信息 dependencies: 依赖包 2). src/manifest.json package: 应用包名 name: 应用名称 versionName: 应用版本 versionCode: 应用号 mainPlatformVersion: 最小平台版本号 icon: 应用图标 permissions: 权限 config: 配置调试级别(debug, log, info, warn, error) router: 页面路由. 用于定义页面的实际地址、跳转地址。如果ux页面没有配置路由，则不参与项目编译。一个目录下最多只能存在一个主页面文件. 其中entry：配置主页，component：页面对应的ux文件名，path：页面路径，不填则默认为页面名称（<ProjectName>/src目录下，页面目录的相对路径） display: UI显示，用于定义与UI显示相关的配置。支持定义：页面公用的默认UI显示、页面私有的UI显示. titleBarBackgroundColor：导航栏颜色; titleBarTextColor：导航栏字体颜色; menu: 是否有菜单; pages：页面私有配置(具体页面具体配置). 2. 调试日志 console.debug('debug') console.log('log') console.info('info') console.warn('warn') console.error('error') 可以使用Android Studio的Android Monitor输出来查看日志。 3. 跳转页面 routeDetail () { // 跳转到应用内的某个页面 router.push ({ uri: '/DemoDetail' }) console.debug('打开新页面') } 4. 生命周期 onInit: 表示VM的数据（events,props,data）已经准备好 onReady: 表示VM的模板已经编译完成 onShow:显示其中一个页面 onHide: 隐藏其中一个页面 onDestroy: 释放资源 onBackPress: 用户点击返回实体按键、左上角返回菜单、调用返回API时触发该事件 onMenuPress: 菜单返回时调用

2018-03-26

COMPASS项目CI实践

这篇文章大体上是从COMPASS整个项目组的角度介绍CI实践的一些经验和成果，但有些部分偏重于从QA的视角看CI给我们的工作带来的变化。

2018-02-02

单元测试实践

说在前面的话：就像阿里规约里提到, 单元测试需要满足的AIR原则： A：Automatic（自动化） I：Independent（独立性） R：Repeatable（可重复）工欲善其事,必先利其器. 单元测试三剑客： TestNg：单元测试框架 AssertJ：断言工具 Jmockit：mock工具 TestNg testNg是个unit test/sut框架, 支持很多功能。但本篇文章重点不是介绍testNg,简单提一下我觉得比较有用的功能 Group：测试用例分组,根据业务/逻辑分组,以更小的粒度来执行case. Parallel：并行执行,可以配置多个线程来执行case.需要注意并发问题. <suite name="My suite" thread-count="10" parallel="classes"> <test name="mocking"> <packages> <package name="com.hz.constantine.jmockit.slideshare.mocking"/> </packages> </test> <test name="faking"> <packages> <package name="com.hz.constantine.jmockit.slideshare.faking"/> </packages> </test> <test name="testng"> <packages> <package name="com.hz.constantine.jmockit.slideshare.testng"/> </packages> </test> </suite> Listener：通过监听器集成自定义的功能 DataProvider：测试用例和测试数据分离 static final String expectData = DataProviderTest.class.getSimpleName(); static final class DataProvider{ @org.testng.annotations.DataProvider(name = "str") public static Object[][] provide(){ return new Object[][]{{expectData}}; } } @Test(dataProvider = "str",dataProviderClass = DataProvider.class) public void dataProviderTest(String data){ Assert.assertEquals(data,expectData); } Timeout/ExpectExceptions：支持用例执行超时和异常 @Test(timeOut = 5,expectedExceptions = {ThreadTimeoutException.class,NullPointerException.class}) public void timeout(){ try { Thread.sleep(10); } catch (InterruptedException e) { } } Tips:附上TestNg Tutorial, http://testng.org/doc/documentation-main.html TestNg 集成Jmockit Java instrumentation：开发者可以构建一个独立于应用程序的代理程序，监测和协助运行在JVM上的程序，虚拟机级别的AOP实现 TestNg Listener: TestNg Listener特性提供开发者扩展TestNg的能力. Jmockit 在jmockit的世界里，它提供两套不同的语法和api. 分别是mocking和faking.下面分别针对这两套做详细的说明 -1- mocking 注解特性 Expectations.代表一组调用关联到当期的case. Record-Replay-Verify Mode. Record: 预准备依赖和数据. Replay:执行业务. Verify:校验. RecordingResult FlexibleArgumentTest Delegate表达式 Caputring: 用在Verification里. CasCadeMock: 级联Mock 其中最重要的是Record-Replay-Verify Mode ,三段式的表述方式。即 Record: 记录,即定义数据、并mock相关的依赖. Replay:回放,即执行被测试的业务逻辑. Verify:校验,即校验逻辑是否正确.废话不多说，直接上代码： @Test(expectedExceptions = MissingInvocation.class) public void recordReplyVerifyNotInOrder() { //Record ClassUnderTest classUnderTestInstance = newClassUnderTestInstance(); final String data = this.getClass().getSimpleName(); new Expectations(classUnderTestInstance.getEye(), classUnderTestInstance.getRepository()) { { classUnderTestInstance.getEye().find(); result = data; classUnderTestInstance.getRepository().insert(data); times = 1; } }; //Replay classUnderTestInstance.action(); //Verify new VerificationsInOrder(){ { classUnderTestInstance.getRepository().insert(data); classUnderTestInstance.getEye().find(); } }; } 其中 ClassUnderTest 是被测试类，依赖了Eye 和 Repository, 在Record阶段被定义了mocking. 其他特性的测试类，可以参看我的github: https://github.com/cscpswang/java-practice -2- faking Faking unspecifiedFaking Invocation Context第2个和第3个特性依然可以参看我的github，重点说明一下特性1: 1.定义一个被测试对象，一个echoServer(在io编程中，echoServer表示接受到任何消息不做处理,直接返回原消息) class EchoServer { private Dependency dependency=new Dependency(); public String echo(String msg) { return msg; } public String run(){ return dependency.run(); } } 2.定义一个依赖类，这个类会在单测中被faking. class Dependency { public String run(){ return "dependency run"; } } 3.case,测试EchoServer. public void applyFakesWithDependency(){ final String msg = "i'm constantine"; EchoServer echoServer = new EchoServer(); final class DependencyMock extends MockUp<Dependency> { @Mock public String run(){ return msg; } } new DependencyMock(); String actualMsg = echoServer.run(); Assert.assertEquals(actualMsg,msg); } tips: spring 中使用faking api时泛型指定到具体的impl类. 被jdk 代理的类(如spring bean被aop),并不是实现类的实例. 所以要么基于接口mocking(需要mock接口的所有方法),要么使用faking. 小结: Faking和Mocking是两套jmockit的api,在其官方文档，有下面一句话： In particular, the use ofboththe Faking API and the Mocking API in the same test class should be viewed with suspicion, as it strongly indicates misuse. 我更偏爱使用Mocking api, 因为它的特性很酷。但它不能mocking私有方法，这点有时会不太方便。最后，如果你要下jmockit的源码，并希望研究，注意一个坑。由于jmockit基于java agent(instrumentation),你需要在你的classpath下放置一个jmockit-xxx.jar.

2018-01-14

实践android的RadioButton

一个一个组件的实习过来。 package com.tw.flag.ch02_button; import android.content.Context; import android.graphics.Color; import android.os.Bundle; import android.os.Vibrator; import android.support.design.widget.FloatingActionButton; import android.support.design.widget.Snackbar; import android.support.v7.app.AppCompatActivity; import android.support.v7.widget.Toolbar; import android.text.Editable; import android.text.TextWatcher; import android.view.MotionEvent; import android.view.View; import android.view.Menu; import android.view.MenuItem; import android.widget.Button; import android.widget.EditText; import android.widget.RadioGroup; import android.widget.TextView; import java.util.Random; public class MainActivity extends AppCompatActivity implements RadioGroup.OnCheckedChangeListener, TextWatcher{ RadioGroup unit; EditText value; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); setSupportActionBar(toolbar); FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab); fab.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG) .setAction("Action", null).show(); } }); unit = (RadioGroup) findViewById(R.id.unit); unit.setOnCheckedChangeListener(this); value = (EditText) findViewById(R.id.value); value.addTextChangedListener(this); } @Override public void onCheckedChanged(RadioGroup group, int checkedId) { calc(); } @Override public void beforeTextChanged(CharSequence s, int start, int count, int after) { } @Override public void onTextChanged(CharSequence s, int start, int before, int count) { } @Override public void afterTextChanged(Editable s) { calc(); } protected void calc() { TextView degF = (TextView)findViewById(R.id.degF); TextView degC = (TextView)findViewById(R.id.degC); double f, c; if (unit.getCheckedRadioButtonId() == R.id.unitF) { f = Double.parseDouble(value.getText().toString()); c = (f - 32) * 5/9; } else { c = Double.parseDouble(value.getText().toString()); f = c * 9/5 + 32; } degC.setText(String.format("%.1f", c) + getResources().getString(R.string.charC)); degF.setText(String.format("%.1f", f) + getResources().getString(R.string.charF)); } }

2017-12-08

Mongodb基础实践（二）

在前面的文章里面主要介绍了MongoDB的文档，集合，数据库等操作和对文档的增、删、改相关知识，接下来会总结一点有关查询的相关知识。在MySQL中,我们知道数据查询是优化的主要内容，读写分离等技术都是可以用来处理数据库查询优化的，足以见数据库查询是每个系统中很重要的一部分，之前介绍了find的简单使用，下面会介绍一些相对比较复杂一点的查询。一、数据查询 MySQL数据库中主要是用select 结合where子句实现数据的查询，功能特别强大，例如多表联合查询、支持正则表达式等。不在这里做过多的相关介绍。这里主要介绍MongoDB的相关查询，MongoDB中主要用find()实现数据的查询，同时也可以使用一些条件限制。 1.1显示单条数据在上篇文章中提到了find()的使用，但是每次查询数据，都是查询所有的，显示其中的一部分，可以用it迭代。有时候我们想要查询其中的一条数据，具体操作要根据具体需求实现。 MongoDB 查询数据的语法 1 db.collection. find (query,projection) query ：可选，使用查询操作符指定查询条件 projection ：可选，使用投影操作符指定返回的键。查询时返回文档中所有键值，只需省略该参数即可（默认省略）。可以使用 pretty() 方法以易读的方式来读取数据，，语法格式如下 1 >db.col. find ().pretty() pretty() 方法以格式化的方式来显示所有文档。例如： 1 2 3 4 5 6 7 8 9 10 11 db.winner. find ().pretty() { "_id" :ObjectId( "592e7d1caaa464fa8a557e95" ), "winne" :1955} { "_id" :ObjectId( "592e7d1eaaa464fa8a557e96" ), "winne" :1955} { "_id" :ObjectId( "592e7d1faaa464fa8a557e97" ), "winne" :1955} { "_id" :ObjectId( "592e7d1faaa464fa8a557e98" ), "winne" :1955} { "_id" :ObjectId( "592e7d21aaa464fa8a557e99" ), "winne" :1955} { "_id" :ObjectId( "592e7d22aaa464fa8a557e9a" ), "winne" :1955} { "_id" :ObjectId( "592e7e14aaa464fa8a557ec4" ), "winne" :41} { "_id" :ObjectId( "592e7e14aaa464fa8a557ec5" ), "winne" :42} { "_id" :ObjectId( "592e7e14aaa464fa8a557ec6" ), "winne" :43} { "_id" :ObjectId( "592e7e14aaa464fa8a557ec7" ), "winne" :44} 1、查询某个集合中的所有数据 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 db.winner. find () { "_id" :ObjectId( "592e7d1caaa464fa8a557e95" ), "winne" :1955} { "_id" :ObjectId( "592e7d1eaaa464fa8a557e96" ), "winne" :1955} { "_id" :ObjectId( "592e7d1faaa464fa8a557e97" ), "winne" :1955} { "_id" :ObjectId( "592e7d1faaa464fa8a557e98" ), "winne" :1955} { "_id" :ObjectId( "592e7d21aaa464fa8a557e99" ), "winne" :1955} { "_id" :ObjectId( "592e7d22aaa464fa8a557e9a" ), "winne" :1955} { "_id" :ObjectId( "592e7e14aaa464fa8a557ec4" ), "winne" :41} { "_id" :ObjectId( "592e7e14aaa464fa8a557ec5" ), "winne" :42} { "_id" :ObjectId( "592e7e14aaa464fa8a557ec6" ), "winne" :43} { "_id" :ObjectId( "592e7e14aaa464fa8a557ec7" ), "winne" :44} { "_id" :ObjectId( "592e7e14aaa464fa8a557ec8" ), "winne" :45} { "_id" :ObjectId( "592e7e14aaa464fa8a557ec9" ), "winne" :46} { "_id" :ObjectId( "592e7e14aaa464fa8a557eca" ), "winne" :47} { "_id" :ObjectId( "592e7e14aaa464fa8a557ecb" ), "winne" :48} { "_id" :ObjectId( "592e7e14aaa464fa8a557ecc" ), "winne" :49} { "_id" :ObjectId( "592e7e14aaa464fa8a557ecd" ), "winne" :50} { "_id" :ObjectId( "592e7e14aaa464fa8a557ece" ), "winne" :51} { "_id" :ObjectId( "592e7e14aaa464fa8a557ecf" ), "winne" :52} { "_id" :ObjectId( "592e7e14aaa464fa8a557ed0" ), "winne" :53} { "_id" :ObjectId( "592e7e14aaa464fa8a557ed1" ), "winne" :54} Type "it" for more 默认显示20条数据，其他数据可以输入it迭代。 2、显示一条数据 find()是输出所有结果，里面可能有些文档内容相同，但是“_id”肯定是不一样的，这时我们可以使用findOne()方法查询，或者可以使用db.winner.find({winne:1955}).limit(1)。 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 db.winner. find ({winne:1955}) { "_id" :ObjectId( "592e7d1caaa464fa8a557e95" ), "winne" :1955} { "_id" :ObjectId( "592e7d1eaaa464fa8a557e96" ), "winne" :1955} { "_id" :ObjectId( "592e7d1faaa464fa8a557e97" ), "winne" :1955} { "_id" :ObjectId( "592e7d1faaa464fa8a557e98" ), "winne" :1955} { "_id" :ObjectId( "592e7d21aaa464fa8a557e99" ), "winne" :1955} { "_id" :ObjectId( "592e7d22aaa464fa8a557e9a" ), "winne" :1955} 假如要查询winner集合中winne=1955的一条数据，而用 find ()查询出所有的数据，这时就可以使用findOne() db.winner.findOne({winne:1955}) { "_id" :ObjectId( "592e7d1caaa464fa8a557e95" ), "winne" :1955} 或者可以使用 db.winner. find ({winne:1955}).limit(1) { "_id" :ObjectId( "592e7d1caaa464fa8a557e95" ), "winne" :1955} 两者的区别 findOne()有点类似MySQL里面的distinct,会返回查询的第一条结果，如果搜索不到想要的数据就会返回NULL， db.winner.findOne({winne:200888}) null db.winner. find ({winne:1955}).limit(1)方法就和MySQL里面的limit是一样的，主要是限制查询结果的条数。 3、查询满足一定条件的数据在MySQL中查询时，可以结合where以及字段等信息查询数据，而MongoDB中也是可以的，同样可以支持一些条件判断语句。格式范例 RDBMS中的类似语句等于 {<key>:<value>} db.col.find({"winne":"1995"}).pretty() wherewinne= '50' 小于 {<key>:{$lt:<value>}} db.col.find({"winne":{$lt:50}}).pretty() wherewinne< 50 小于或等于 {<key>:{$lte:<value>}} db.col.find({"winne":{$lte:50}}).pretty() wherewinne<= 50 大于 {<key>:{$gt:<value>}} db.col.find({"winne":{$gt:50}}).pretty() wherewinne> 50 大于或等于 {<key>:{$gte:<value>}} db.col.find({"winne":{$gte:50}}).pretty() wherewinne>= 50 不等于 {<key>:{$ne:<value>}} db.col.find({"winne":{$ne:50}}).pretty() wherewinne!= 50 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 $gt--------greaterthan$gte---------gtequal $lt-------- less than$lte---------ltequal $ ne -----------notequal 1、查询winner集合中winne<50的相关数据 db.winner. find ({winne:{$lt:50}}) { "_id" :ObjectId( "592e7e14aaa464fa8a557ec4" ), "winne" :41} { "_id" :ObjectId( "592e7e14aaa464fa8a557ec5" ), "winne" :42} { "_id" :ObjectId( "592e7e14aaa464fa8a557ec6" ), "winne" :43} { "_id" :ObjectId( "592e7e14aaa464fa8a557ec7" ), "winne" :44} { "_id" :ObjectId( "592e7e14aaa464fa8a557ec8" ), "winne" :45} { "_id" :ObjectId( "592e7e14aaa464fa8a557ec9" ), "winne" :46} { "_id" :ObjectId( "592e7e14aaa464fa8a557eca" ), "winne" :47} { "_id" :ObjectId( "592e7e14aaa464fa8a557ecb" ), "winne" :48} { "_id" :ObjectId( "592e7e14aaa464fa8a557ecc" ), "winne" :49} { "_id" :ObjectId( "592e7e17aaa464fa8a557f28" ), "winne" :41} { "_id" :ObjectId( "592e7e17aaa464fa8a557f29" ), "winne" :42} { "_id" :ObjectId( "592e7e17aaa464fa8a557f2a" ), "winne" :43} { "_id" :ObjectId( "592e7e17aaa464fa8a557f2b" ), "winne" :44} 2、查询winner集合中40=<winne<50的相关数据 db.winner. find ({winne:{$gte:40,$lt:45}}) { "_id" :ObjectId( "592e7e14aaa464fa8a557ec4" ), "winne" :41} { "_id" :ObjectId( "592e7e14aaa464fa8a557ec5" ), "winne" :42} { "_id" :ObjectId( "592e7e14aaa464fa8a557ec6" ), "winne" :43} { "_id" :ObjectId( "592e7e14aaa464fa8a557ec7" ), "winne" :44} { "_id" :ObjectId( "592e7e17aaa464fa8a557f28" ), "winne" :41} { "_id" :ObjectId( "592e7e17aaa464fa8a557f29" ), "winne" :42} { "_id" :ObjectId( "592e7e17aaa464fa8a557f2a" ), "winne" :43} { "_id" :ObjectId( "592e7e17aaa464fa8a557f2b" ), "winne" :44} { "_id" :ObjectId( "592e7e18aaa464fa8a557f8c" ), "winne" :41} { "_id" :ObjectId( "592e7e18aaa464fa8a557f8d" ), "winne" :42} { "_id" :ObjectId( "592e7e18aaa464fa8a557f8e" ), "winne" :43} { "_id" :ObjectId( "592e7e18aaa464fa8a557f8f" ), "winne" :44} 4、MongoDB AND 条件 MongoDB 的 find() 方法可以传入多个键(key)，每个键(key)以逗号隔开，语法格式如下： >db.winner.find({key1:value1, key2:value2}).pretty() 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 #插入测试数据 for (i=0;i<20;i++)db.info2.insert({name: "linux" , object: "SA" , company: "docker" , phone:i}) for (i=0;i<20;i++)db.info2.insert({name: "openstack" , object: "DBA" , company: "could" , phone:i}) #检查测试数据 >db.info2. find () db.info2. find () { "_id" :ObjectId( "592f838dd276944818f7edb4" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :0} { "_id" :ObjectId( "592f838dd276944818f7edb5" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :1} { "_id" :ObjectId( "592f838dd276944818f7edb6" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :2} { "_id" :ObjectId( "592f838dd276944818f7edb7" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :3} { "_id" :ObjectId( "592f838dd276944818f7edb8" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :4} { "_id" :ObjectId( "592f838dd276944818f7edb9" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :5} { "_id" :ObjectId( "592f838dd276944818f7edba" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :6} { "_id" :ObjectId( "592f838dd276944818f7edbb" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :7} { "_id" :ObjectId( "592f838dd276944818f7edbc" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :8} { "_id" :ObjectId( "592f838dd276944818f7edbd" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :9} { "_id" :ObjectId( "592f838dd276944818f7edbe" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :10} { "_id" :ObjectId( "592f838dd276944818f7edbf" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :11} { "_id" :ObjectId( "592f838dd276944818f7edc0" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :12} { "_id" :ObjectId( "592f838dd276944818f7edc1" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :13} { "_id" :ObjectId( "592f838dd276944818f7edc2" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :14} { "_id" :ObjectId( "592f838dd276944818f7edc3" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :15} { "_id" :ObjectId( "592f838dd276944818f7edc4" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :16} { "_id" :ObjectId( "592f838dd276944818f7edc5" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :17} { "_id" :ObjectId( "592f838dd276944818f7edc6" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :18} { "_id" :ObjectId( "592f838dd276944818f7edc7" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :19} >db.info2. find ().count() #检查数据的条数 40 #筛选name=linuxobject=SAphone<5 db.info2. find ({name: "linux" ,object: "SA" ,phone:{$lt:5}}) 执行 db.info2. find ({name: "linux" ,object: "SA" ,phone:{$lt:5}}) { "_id" :ObjectId( "592f838dd276944818f7edb4" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :0} { "_id" :ObjectId( "592f838dd276944818f7edb5" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :1} { "_id" :ObjectId( "592f838dd276944818f7edb6" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :2} { "_id" :ObjectId( "592f838dd276944818f7edb7" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :3} { "_id" :ObjectId( "592f838dd276944818f7edb8" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :4} 筛选name=linuxobject=SA5<phone<=10 db.info2. find ({name: "linux" ,object: "SA" ,phone:{ "$gt" :5, "$lte" :10}}) db.info2. find ({name: "linux" ,object: "SA" ,phone:{ "$gt" :5, "$lte" :10}}) { "_id" :ObjectId( "592f838dd276944818f7edba" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :6} { "_id" :ObjectId( "592f838dd276944818f7edbb" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :7} { "_id" :ObjectId( "592f838dd276944818f7edbc" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :8} { "_id" :ObjectId( "592f838dd276944818f7edbd" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :9} { "_id" :ObjectId( "592f838dd276944818f7edbe" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :10} 筛选5<phone<=10 db.info2. find ({phone:{ "$gt" :5, "$lte" :10}}) { "_id" :ObjectId( "592f838dd276944818f7edba" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :6} { "_id" :ObjectId( "592f838dd276944818f7edbb" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :7} { "_id" :ObjectId( "592f838dd276944818f7edbc" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :8} { "_id" :ObjectId( "592f838dd276944818f7edbd" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :9} { "_id" :ObjectId( "592f838dd276944818f7edbe" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :10} { "_id" :ObjectId( "592f838fd276944818f7edce" ), "name" : "openstack" , "object" : "DBA" , "company" : "could" , "phone" :6} { "_id" :ObjectId( "592f838fd276944818f7edcf" ), "name" : "openstack" , "object" : "DBA" , "company" : "could" , "phone" :7} { "_id" :ObjectId( "592f838fd276944818f7edd0" ), "name" : "openstack" , "object" : "DBA" , "company" : "could" , "phone" :8} { "_id" :ObjectId( "592f838fd276944818f7edd1" ), "name" : "openstack" , "object" : "DBA" , "company" : "could" , "phone" :9} { "_id" :ObjectId( "592f838fd276944818f7edd2" ), "name" : "openstack" , "object" : "DBA" , "company" : "could" , "phone" :10} 5 MongoDB OR 条件 MongoDB 除了有类似MySQL的AND条件语句外，还有OR 条件语句，OR 条件语句使用了关键字 $or,语法格式如下： >db.collections.find( { $or: [ {key1: value1}, {key2:value2} ] } ).pretty() 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 #查name=linux或者object=redis db.info2. find ( {$or:[{name: "linux" },{object: "redis" }] } ) db.info2. find (db.info2. find ( ...{$or:[{name: "linux" },{object: "redis" }]{$or:[{name: "linux" },{object: "redis" }] ... ...}} ...)) { "_id" :ObjectId( "592f838dd276944818f7edb4" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :0} { "_id" :ObjectId( "592f838dd276944818f7edb5" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :1} { "_id" :ObjectId( "592f838dd276944818f7edb6" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :2} { "_id" :ObjectId( "592f838dd276944818f7edb7" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :3} { "_id" :ObjectId( "592f838dd276944818f7edb8" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :4} { "_id" :ObjectId( "592f838dd276944818f7edb9" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :5} { "_id" :ObjectId( "592f838dd276944818f7edba" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :6} { "_id" :ObjectId( "592f838dd276944818f7edbb" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :7} { "_id" :ObjectId( "592f838dd276944818f7edbc" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :8} { "_id" :ObjectId( "592f838dd276944818f7edbd" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :9} { "_id" :ObjectId( "592f838dd276944818f7edbe" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :10} { "_id" :ObjectId( "592f838dd276944818f7edbf" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :11} { "_id" :ObjectId( "592f838dd276944818f7edc0" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :12} { "_id" :ObjectId( "592f838dd276944818f7edc1" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :13} { "_id" :ObjectId( "592f838dd276944818f7edc2" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :14} { "_id" :ObjectId( "592f838dd276944818f7edc3" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :15} { "_id" :ObjectId( "592f838dd276944818f7edc4" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :16} { "_id" :ObjectId( "592f838dd276944818f7edc5" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :17} { "_id" :ObjectId( "592f838dd276944818f7edc6" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :18} { "_id" :ObjectId( "592f838dd276944818f7edc7" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :19} Type "it" for more >itit { "_id" :ObjectId( "592f8964d276944818f7eddc" ), "name" : "MongoDB" , "object" : "redis" , "company" : "winner" , "phone" :0} { "_id" :ObjectId( "592f8964d276944818f7eddd" ), "name" : "MongoDB" , "object" : "redis" , "company" : "winner" , "phone" :1} { "_id" :ObjectId( "592f8964d276944818f7edde" ), "name" : "MongoDB" , "object" : "redis" , "company" : "winner" , "phone" :2} { "_id" :ObjectId( "592f8964d276944818f7eddf" ), "name" : "MongoDB" , "object" : "redis" , "company" : "winner" , "phone" :3} { "_id" :ObjectId( "592f8964d276944818f7ede0" ), "name" : "MongoDB" , "object" : "redis" , "company" : "winner" , "phone" :4} { "_id" :ObjectId( "592f8964d276944818f7ede1" ), "name" : "MongoDB" , "object" : "redis" , "company" : "winner" , "phone" :5} { "_id" :ObjectId( "592f8964d276944818f7ede2" ), "name" : "MongoDB" , "object" : "redis" , "company" : "winner" , "phone" :6} { "_id" :ObjectId( "592f8964d276944818f7ede3" ), "name" : "MongoDB" , "object" : "redis" , "company" : "winner" , "phone" :7} { "_id" :ObjectId( "592f8964d276944818f7ede4" ), "name" : "MongoDB" , "object" : "redis" , "company" : "winner" , "phone" :8} { "_id" :ObjectId( "592f8964d276944818f7ede5" ), "name" : "MongoDB" , "object" : "redis" , "company" : "winner" , "phone" :9} 6、AND和OR综合使用查询phone<5,name=MongoDB或者name=linux 1 2 3 4 5 6 7 8 9 10 11 12 db.info2. find ({phone:{$lt:5},$or:[{name: "MongoDB" },{name: "linux" }]}) db.info2. find ({phone:{$lt:5},$or:[{name: "MongoDB" },{name: "linux" }]}) { "_id" :ObjectId( "592f838dd276944818f7edb4" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :0} { "_id" :ObjectId( "592f838dd276944818f7edb5" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :1} { "_id" :ObjectId( "592f838dd276944818f7edb6" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :2} { "_id" :ObjectId( "592f838dd276944818f7edb7" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :3} { "_id" :ObjectId( "592f838dd276944818f7edb8" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :4} { "_id" :ObjectId( "592f8964d276944818f7eddc" ), "name" : "MongoDB" , "object" : "redis" , "company" : "winner" , "phone" :0} { "_id" :ObjectId( "592f8964d276944818f7eddd" ), "name" : "MongoDB" , "object" : "redis" , "company" : "winner" , "phone" :1} { "_id" :ObjectId( "592f8964d276944818f7edde" ), "name" : "MongoDB" , "object" : "redis" , "company" : "winner" , "phone" :2} { "_id" :ObjectId( "592f8964d276944818f7eddf" ), "name" : "MongoDB" , "object" : "redis" , "company" : "winner" , "phone" :3} { "_id" :ObjectId( "592f8964d276944818f7ede0" ), "name" : "MongoDB" , "object" : "redis" , "company" : "winner" , "phone" :4} 7、查询结果排序在MySQL中是有order by条件，可以根据desc或者asc进行升序或者降序操作，而MongoDB中是可以利用sort()方法实现排序的，例如对6中的结果处理，根据phone排序。基本语法 db.info2.find().sort({phone:1})#这里phone表示根据该key排序，1表示升序，-1表示降序。 1 2 3 4 5 6 7 8 9 10 11 db.info2. find ({phone:{$lt:5},$or:[{name: "MongoDB" },{name: "linux" }]}). sort ({phone:1}) { "_id" :ObjectId( "592f838dd276944818f7edb4" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :0} { "_id" :ObjectId( "592f8964d276944818f7eddc" ), "name" : "MongoDB" , "object" : "redis" , "company" : "winner" , "phone" :0} { "_id" :ObjectId( "592f838dd276944818f7edb5" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :1} { "_id" :ObjectId( "592f8964d276944818f7eddd" ), "name" : "MongoDB" , "object" : "redis" , "company" : "winner" , "phone" :1} { "_id" :ObjectId( "592f838dd276944818f7edb6" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :2} { "_id" :ObjectId( "592f8964d276944818f7edde" ), "name" : "MongoDB" , "object" : "redis" , "company" : "winner" , "phone" :2} { "_id" :ObjectId( "592f838dd276944818f7edb7" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :3} { "_id" :ObjectId( "592f8964d276944818f7eddf" ), "name" : "MongoDB" , "object" : "redis" , "company" : "winner" , "phone" :3} { "_id" :ObjectId( "592f838dd276944818f7edb8" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :4} { "_id" :ObjectId( "592f8964d276944818f7ede0" ), "name" : "MongoDB" , "object" : "redis" , "company" : "winner" , "phone" :4} 8、MongoDB Skip() 方法在前面介绍了limit()，sort()，count()等方法，接下来要介绍一个比较有趣的skip()方法，在使用limit()的时候可以显示你要求的几条，而skip()方法是跳过几条。 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 db.info2. find ({phone:{$lt:5},$or:[{name: "MongoDB" },{name: "linux" }]}). sort ({phone:1}) { "_id" :ObjectId( "592f838dd276944818f7edb4" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :0} { "_id" :ObjectId( "592f8964d276944818f7eddc" ), "name" : "MongoDB" , "object" : "redis" , "company" : "winner" , "phone" :0} { "_id" :ObjectId( "592f838dd276944818f7edb5" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :1} { "_id" :ObjectId( "592f8964d276944818f7eddd" ), "name" : "MongoDB" , "object" : "redis" , "company" : "winner" , "phone" :1} { "_id" :ObjectId( "592f838dd276944818f7edb6" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :2} { "_id" :ObjectId( "592f8964d276944818f7edde" ), "name" : "MongoDB" , "object" : "redis" , "company" : "winner" , "phone" :2} { "_id" :ObjectId( "592f838dd276944818f7edb7" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :3} { "_id" :ObjectId( "592f8964d276944818f7eddf" ), "name" : "MongoDB" , "object" : "redis" , "company" : "winner" , "phone" :3} { "_id" :ObjectId( "592f838dd276944818f7edb8" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :4} { "_id" :ObjectId( "592f8964d276944818f7ede0" ), "name" : "MongoDB" , "object" : "redis" , "company" : "winner" , "phone" :4} 使用skip()方法 db.info2. find ({phone:{$lt:5},$or:[{name: "MongoDB" },{name: "linux" }]}). sort ({phone:1}).skip(3) { "_id" :ObjectId( "592f8964d276944818f7eddd" ), "name" : "MongoDB" , "object" : "redis" , "company" : "winner" , "phone" :1} { "_id" :ObjectId( "592f838dd276944818f7edb6" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :2} { "_id" :ObjectId( "592f8964d276944818f7edde" ), "name" : "MongoDB" , "object" : "redis" , "company" : "winner" , "phone" :2} { "_id" :ObjectId( "592f838dd276944818f7edb7" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :3} { "_id" :ObjectId( "592f8964d276944818f7eddf" ), "name" : "MongoDB" , "object" : "redis" , "company" : "winner" , "phone" :3} { "_id" :ObjectId( "592f838dd276944818f7edb8" ), "name" : "linux" , "object" : "SA" , "company" : "docker" , "phone" :4} { "_id" :ObjectId( "592f8964d276944818f7ede0" ), "name" : "MongoDB" , "object" : "redis" , "company" : "winner" , "phone" :4} skip方法有点类似于MySQL里面的limit之间间隔情况。这里介绍了有关查询的问题，在数据库中，查询是非常重要的一部分，所以介绍的篇幅也是比较多的，后期遇到其他问题也会继续总结输出。本文转自 tianya1993 51CTO博客，原文链接：http://blog.51cto.com/dreamlinux/1931384，如需转载请自行联系原作者

2017-11-26

资源下载

更多资源

腾讯云软件源

为解决软件依赖安装时官方源访问速度慢的问题，腾讯云为一些软件搭建了缓存服务。您可以通过使用腾讯云软件源站来提升依赖包的安装速度。为了方便用户自由搭建服务架构，目前腾讯云软件源站支持公网访问和内网访问。

Nacos

Nacos /nɑ:kəʊs/ 是 Dynamic Naming and Configuration Service 的首字母简称，一个易于构建 AI Agent 应用的动态服务发现、配置管理和AI智能体管理平台。Nacos 致力于帮助您发现、配置和管理微服务及AI智能体应用。Nacos 提供了一组简单易用的特性集，帮助您快速实现动态服务发现、服务配置、服务元数据、流量管理。Nacos 帮助您更敏捷和容易地构建、交付和管理微服务平台。

Rocky Linux

Rocky Linux（中文名：洛基）是由Gregory Kurtzer于2020年12月发起的企业级Linux发行版，作为CentOS稳定版停止维护后与RHEL（Red Hat Enterprise Linux）完全兼容的开源替代方案，由社区拥有并管理，支持x86_64、aarch64等架构。其通过重新编译RHEL源代码提供长期稳定性，采用模块化包装和SELinux安全架构，默认包含GNOME桌面环境及XFS文件系统，支持十年生命周期更新。

WebStorm

WebStorm 是jetbrains公司旗下一款JavaScript 开发工具。目前已经被广大中国JS开发者誉为“Web前端开发神器”、“最强大的HTML5编辑器”、“最智能的JavaScript IDE”等。与IntelliJ IDEA同源，继承了IntelliJ IDEA强大的JS部分的功能。