Memcached安装教程及使用
Memcached
Memcached 是一个高性能的分布式内存对象缓存系统，用于动态Web应用以减轻数据库负载
Table of contents
安装
- 下载下来memcached.exe
- 切换到memcached.exe所在路径
- 输入memcached -d install
- win + r 输入 services.msc打开window服务
- 随便选中一个输入memcached就可以查看到安装好的服务,右击启动它,然后关闭窗口
使用
- 新建java工程或者maven工程
- 导入三个必备的依赖,
fastjson-1.2.3,slf4j-api-1.7.5,xmemcached-2.3.2 -
main方法中加入
MemcachedClientBuilder builder = new XMemcachedClientBuilder(AddrUtil.getAddresses("127.0.0.1:11211")); builder.setSessionLocator(new KetamaMemcachedSessionLocator()); try { MemcachedClient memcachedClient =builder.build(); //在这里写入测试代码 memcachedClient.shutdown(); } catch (IOException e) { e.printStackTrace(); } catch (InterruptedException e) { e.printStackTrace(); } catch (MemcachedException e) { e.printStackTrace(); } catch (TimeoutException e) { e.printStackTrace(); }
时效
memcachedClient.set("testTime",2,"testTimeValue");
String testTime = memcachedClient.get("testTime");
System.out.println("testTime = " + testTime);
TimeUnit.SECONDS.sleep(4);
System.out.println("4s 过去了");
String valueExist = memcachedClient.get(testTime);
System.out.println("valueExist = " + valueExist); 输出:
testTime = testTimeValue
4s 过去了
valueExist = null
恢复
//存储,然后关闭掉服务
memcachedClient.set("test",0,"testValue");
String testTime=memcachedClient.get("test");
System.out.println("testTime="+testTime);
System.out.println("存储成功"); 输出:
testTime = testValue
存储成功
//关闭掉服务后的重启
String testTime = memcachedClient.get("test");
System.out.println("testTime = " + testTime);
System.out.println("取值失败"); 输出:
testTime = null
取值失败
delete
memcachedClient.set("test",0,"testValue");
String getVal = memcachedClient.get("test");
System.out.println("getVal = " + getVal);
memcachedClient.delete("test");
System.out.println("after delete ...");
getVal = memcachedClient.get("test");
System.out.println("getVal = " + getVal); 输出:
getVal = testValue
after delete ...
getVal = null
自动增长
//三个参数,第一个指定键,第二个指定递增的幅度大小,第三个指定当key不存在的情况下的初始值
for (int i = 0; i < 5; i++) {
memcachedClient.incr("博客的赞",1,20);
String point = memcachedClient.get("博客的赞");
System.out.println("point = " + point);
} 输出:
point = 20
point = 21
point = 22
point = 23
point = 24
关于incr的用法,值得警惕的是,它的值虽然看起来是一个数字,实际上正如代码中的String point = memcachedClient.get("博客的赞");
其实是一个字符串,所以会出现如下错误
memcachedClient.set("博客的赞1",0,10);
int str = memcachedClient.get("博客的赞1");
System.out.println("str1 = " + str);
memcachedClient.incr("博客的赞1",2,22);
str = memcachedClient.get("博客的赞1");
System.out.println("str2 = " + str); 输出:
net.rubyeye.xmemcached.exception.MemcachedClientException: cannot increment or decrement non-numeric value,key=博客的赞1
at net.rubyeye.xmemcached.command.Command.decodeError(Command.java:267)
..
at com.google.code.yanf4j.nio.impl.NioController.onRead(NioController.java:157)
at com.google.code.yanf4j.nio.impl.Reactor.dispatchEvent(Reactor.java:323)
at com.google.code.yanf4j.nio.impl.Reactor.run(Reactor.java:180)
str1 = 10
输出的顺序不同,注意输出的异常栈信息的第一条和后面的几条就指明nio.impl.Reactor.run,线程的,这儿就不深入展开了
spring
- 新建一个maven工程
- pom.xml
- 在resource中新建sping-config.xml
- spring单元测试代码骨架
- 测试代码
骨架
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = "classpath:spring-config.xml")
public class TestMem {
@Autowired
private MemcachedClient memcachedClient;
@Test
public void test1(){
//测试代码部分
}
} 测试代码
memcachedClient.set("springData",3,"dataVal");
String str = memcachedClient.get("springData");
System.out.println("str = " + str); 输出:
str = dataVal
还可以存储对象,不过该对象必须实现Serializable接口,不然会报错java.io.NotSerializableException: Teacher,
实现接口后
import lombok.Data;
import java.io.Serializable;
@Data
public class Teacher implements Serializable {
private int age;
private String name;
} 关于@Data关我在另一篇博客中有介绍lombok
Teacher teacher = new Teacher();
teacher.setAge(3);
teacher.setName("23");
memcachedClient.set("te", 0, teacher);
Teacher teacher1 = memcachedClient.get("te");
System.out.println("teacher1 = " + teacher1);输出:
teacher1 = Teacher(age=3, name=23)
pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.selton</groupId>
<artifactId>DemoMemSpring</artifactId>
<version>1.0</version>
<dependencies>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.18.0</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>4.3.11.RELEASE</version>
</dependency>
<dependency>
<groupId>com.googlecode.xmemcached</groupId>
<artifactId>xmemcached</artifactId>
<version>2.0.0</version>
<exclusions>
<exclusion>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<version>4.3.11.RELEASE</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
</dependencies>
</project> config
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd
">
<bean id="memcachedClient" name="memcachedClient"
class="net.rubyeye.xmemcached.utils.XMemcachedClientFactoryBean">
<property name="servers">
<!--配置端口,另加入的话,空格隔开-->
<value>127.0.0.1:11211</value>
</property>
<property name="weights">
<list>
<!--设置不同端口的权重,这里只有一个端口-->
<value>1</value>
</list>
</property>
<property name="sessionLocator">
<bean class="net.rubyeye.xmemcached.impl.KetamaMemcachedSessionLocator"></bean>
</property>
<property name="transcoder">
<bean class="net.rubyeye.xmemcached.transcoders.SerializingTranscoder" />
</property>
<property name="bufferAllocator">
<bean class="net.rubyeye.xmemcached.buffer.SimpleBufferAllocator"></bean>
</property>
</bean>
</beans>
