Hadoop HDFS编程 API入门系列之合并小文件到HDFS（三）
代码版本1
1 package zhouls.bigdata.myWholeHadoop.HDFS.hdfs7; 2 3 import java.io.IOException; 4 import java.net.URI; 5 import java.net.URISyntaxException; 6 import org.apache.hadoop.conf.Configuration; 7 import org.apache.hadoop.fs.FSDataInputStream; 8 import org.apache.hadoop.fs.FSDataOutputStream; 9 import org.apache.hadoop.fs.FileStatus; 10 import org.apache.hadoop.fs.FileSystem; 11 import org.apache.hadoop.fs.FileUtil; 12 import org.apache.hadoop.fs.Path; 13 import org.apache.hadoop.fs.PathFilter; 14 import org.apache.hadoop.io.IOUtils; 15 /** 16 * function 合并小文件至 HDFS 17 * 18 * 19 */ 20 public class MergeSmallFilesToHDFS 21 { 22 private static FileSystem fs = null; //定义文件系统对象，是HDFS上的 23 private static FileSystem local = null; //定义文件系统对象，是本地上的 24 25 /** 26 * @function main 27 * @param args 28 * @throws IOException 29 * @throws URISyntaxException 30 */ 31 32 public static void main(String[] args) throws IOException,URISyntaxException{ 33 34 list(); 35 } 36 37 /** 38 * 39 * @throws IOException 40 * @throws URISyntaxException 41 */ 42 public static void list() throws IOException, URISyntaxException{ 43 // 读取hadoop配置文件 44 Configuration conf = new Configuration(); 45 // 文件系统访问接口和创建FileSystem对象，在本地上运行模式 46 URI uri = new URI("hdfs://HadoopMaster:9000"); 47 fs = FileSystem.get(uri, conf); 48 // 获得本地文件系统 49 local = FileSystem.getLocal(conf); 50 // 过滤目录下的 svn 文件 51 FileStatus[] dirstatus = local.globStatus(new Path("./data/mergeSmallFilesToHDFS/73/*"),new RegexExcludePathFilter("^.*svn$")); 52 // FileStatus[] dirstatus = local.globStatus(new Path("D://data/73/*"),new RegexExcludePathFilter("^.*svn$")); 53 //获取D:\Data\tvdata目录下的所有文件路径 54 Path[] dirs = FileUtil.stat2Paths(dirstatus); 55 FSDataOutputStream out = null; 56 FSDataInputStream in = null; 57 for (Path dir : dirs) 58 {//比如拿2012-09-17为例 59 //将文件夹名称2012-09-17的-去掉，直接，得到20120901文件夹名称 60 String fileName = dir.getName().replace("-", "");//文件名称 61 //只接受20120917日期目录下的.txt文件 62 FileStatus[] localStatus = local.globStatus(new Path(dir+"/*"),new RegexAcceptPathFilter("^.*txt$")); 63 // 获得20120917日期目录下的所有文件 64 Path[] listedPaths = FileUtil.stat2Paths(localStatus); 65 // 输出路径 66 Path block = new Path("hdfs://HadoopMaster:9000/middle/tv/"+ fileName + ".txt"); 67 System.out.println("合并后的文件名称："+fileName+".txt"); 68 // 打开输出流 69 out = fs.create(block); 70 //循环20120917日期目录下的所有文件 71 for (Path p : listedPaths){//这是星型for循环，即listedPaths的值传给Path p 72 in = local.open(p);// 打开输入流 73 IOUtils.copyBytes(in, out, 4096, false); // 复制数据 74 // 关闭输入流 75 in.close(); 76 } 77 if (out != null){ 78 // 关闭输出流 79 out.close(); 80 } 81 //当循环完20120917日期目录下的所有文件之后，接着依次20120918,20120919,,, 82 } 83 } 84 85 /** 86 * 87 * @function 过滤 regex 格式的文件 88 * 89 */ 90 public static class RegexExcludePathFilter implements PathFilter{ 91 private final String regex; 92 93 public RegexExcludePathFilter(String regex){ 94 this.regex = regex; 95 } 96 97 98 public boolean accept(Path path){ 99 // TODO Auto-generated method stub 100 boolean flag = path.toString().matches(regex); 101 return !flag; 102 } 103 104 } 105 106 /** 107 * 108 * @function 接受 regex 格式的文件 109 * 110 */ 111 public static class RegexAcceptPathFilter implements PathFilter{ 112 private final String regex; 113 114 public RegexAcceptPathFilter(String regex){ 115 this.regex = regex; 116 } 117 118 119 public boolean accept(Path path){ 120 // TODO Auto-generated method stub 121 boolean flag = path.toString().matches(regex); 122 return flag; 123 } 124 125 } 126 }
代码版本2
1 package com.dajiangtai.Hadoop.HDFS; 2 3 import java.io.IOException; 4 import java.net.URI; 5 import java.net.URISyntaxException; 6 import org.apache.hadoop.conf.Configuration; 7 import org.apache.hadoop.fs.FSDataInputStream; 8 import org.apache.hadoop.fs.FSDataOutputStream; 9 import org.apache.hadoop.fs.FileStatus; 10 import org.apache.hadoop.fs.FileSystem; 11 import org.apache.hadoop.fs.FileUtil; 12 import org.apache.hadoop.fs.Path; 13 import org.apache.hadoop.fs.PathFilter; 14 import org.apache.hadoop.hdfs.DistributedFileSystem; 15 import org.apache.hadoop.io.IOUtils; 16 /** 17 * function 合并小文件至 HDFS ， 文件与块大小（比如128M）来比，小的话，称为小文件。是一个相对概念！相对于数据块而言的！ 18 * @author 小讲 19 * 我们利用通配符和PathFilter 对象，将本地多种格式的文件上传至 HDFS文件系统，并过滤掉 txt文本格式以外的文件。 20 */ 21 public class MergeSmallFilesToHDFS { 22 private static FileSystem fs = null; 23 private static FileSystem local = null; 24 /** 25 * @function main 26 * @param args 27 * @throws IOException 28 * @throws URISyntaxException 29 */ 30 public static void main(String[] args) throws IOException, 31 URISyntaxException { 32 list(); 33 } 34 35 /** 36 * 37 * @throws IOException 38 * @throws URISyntaxException 39 */ 40 public static void list() throws IOException, URISyntaxException { 41 // 读取hadoop文件系统的配置 42 Configuration conf = new Configuration(); 43 // conf=Configuration 44 // conf是Configuration: core-default.xml, core-site.xml, mapred-default.xml, mapred-site.xml, yarn-default.xml, yarn-site.xml, hdfs-default.xml, hdfs-site.xml 45 46 //文件系统访问接口 47 URI uri = new URI("hdfs://djt002:9000"); 48 // uri=URI 49 // uri是hdfs://djt002:9000 50 51 // URL、URI与Path三者的区别 52 // Hadoop文件系统中通过Hadoop Path对象来代表一个文件 53 // URL（相当于绝对路径） -> （文件） -> URI（相当于相对路径，即代表URL前面的那一部分） 54 // URI：如hdfs://dajiangtai:9000 55 // 如，URL.openStream 56 57 58 59 //获得FileSystem实例，即HDFS 60 fs = FileSystem.get(uri, conf); 61 // fs=DistributedFileSystem 62 // fs是DFS[DFSClient[clientName=DFSClient_NONMAPREDUCE_1814566850_1, ugi=Administrator (auth:SIMPLE)]] 63 64 //获得FileSystem实例，即Local 65 local = FileSystem.getLocal(conf); 66 // local=LocalFileSystem 67 // local是org.apache.hadoop.fs.LocalFileSystem@3ce1b8c5 68 // 为什么要获取到Local呢，因为，我们要把本地D盘下data/73目录下的文件要合并后，上传到HDFS里，所以，我们需先获取到Local，再来做合并工作啦！ 69 70 71 // 18、列出文件或目录内容(主要是存放文件或目录的元数据，即大小，权限，副本，，，) 72 // public FileStatus[] listStatus(Path f) throws IOException 73 // public FileStatus[] listStatus(Path f,PathFilter filter) throws IOException 74 // PathFilter是路径过滤器 75 // public FileStatus[] listStatus(Path[] files) throws IOException 76 // public FileStatus[] listStatus(Path[] files,PathFilter filter) 77 // 传送Path数组和路径过滤器 78 // 79 // 80 // 19、FileUtil中的stat2Paths()，将一个FileStatus元数据对象数组转换为一个Path对象数组 81 // 82 // 20、(1)使用通配符来匹配多个目录下的多个文件，也是列出文件或目录内容(主要是存放文件或目录的元数据，即大小，权限，副本，，，) 83 // public FileStatus[] globStatus(Path pathPattern) throws IOException 84 // public FileStatus[] globStatus(Path pathPattern,PathFilter filter) throws IOException 85 // 86 // (2)PathFilter对象 87 // public interface PathFilter{ 88 // boolean accpet(Path path); 89 // } 90 91 92 93 //过滤目录下的 svn 文件，globStatus从第一个参数通配符合到文件，剔除满足第二个参数到结果，因为PathFilter中accept是return! 94 FileStatus[] dirstatus = local.globStatus(new Path("D://data/73/*"),new RegexExcludePathFilter("^.*svn$"));//一般这是隐藏文件，所以得排除 95 //dirstatus=FileStatus[7] 96 // dirstatus是[DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-17; isDirectory=true; modification_time=1427791478002; access_time=0; owner=; group=; permission=rwxrwxrwx; isSymlink=false} 97 // , DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-18; isDirectory=true; modification_time=1427791505373; access_time=0; owner=; group=; permission=rwxrwxrwx; isSymlink=false} 98 // , DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-19; isDirectory=true; modification_time=1427791532277; access_time=0; owner=; group=; permission=rwxrwxrwx; isSymlink=false} 99 // , DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-20; isDirectory=true; modification_time=1427791553035; access_time=0; owner=; group=; permission=rwxrwxrwx; isSymlink=false} 100 // , DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-21; isDirectory=true; modification_time=1427791577709; access_time=0; owner=; group=; permission=rwxrwxrwx; isSymlink=false} 101 // , DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-22; isDirectory=true; modification_time=1427791602770; access_time=0; owner=; group=; permission=rwxrwxrwx; isSymlink=false} 102 // , DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-23; isDirectory=true; modification_time=1427791647177; access_time=0; owner=; group=; permission=rwxrwxrwx; isSymlink=false}] 103 104 105 // ^表示匹配我们字符串开始的位置 *代表0到多个字符 $代表字符串结束的位置 106 // RegexExcludePathFilter来只排除我们不需要的，即svn格式 107 // RegexExcludePathFilter这个方法我们自己写 108 109 // 但是我们，最终是要处理文件里的东西，最终是要转成Path类型，因为Path对象f,它对应着一个文件。 110 111 //获取73目录下的所有文件路径，注意FIleUtil中stat2Paths()的使用，它将一个FileStatus对象数组转换为Path对象数组。 112 Path[] dirs = FileUtil.stat2Paths(dirstatus);//dirstatus是FileStatus数组类型 113 // dirs=Path[7] 114 // dirs是 [file:/D:/data/73/2012-09-17 115 // , file:/D:/data/73/2012-09-18 116 // , file:/D:/data/73/2012-09-19 117 // , file:/D:/data/73/2012-09-20 118 // , file:/D:/data/73/2012-09-21 119 // , file:/D:/data/73/2012-09-22 120 // , file:/D:/data/73/2012-09-23] 121 122 123 FSDataOutputStream out = null;//输出流 124 // out=HdfsDaDataOutputStream 125 // out是org.apache.hadoop.hdfs.client.HdfsDataOutputStream@2b11624e 126 127 FSDataInputStream in = null;//输入流 128 // in=ChecksumFileSystem&FSDataBoundedInputStream 129 // in是org.apache.hadoop.fs.ChecksumFileSystem$FSDataBoundedInputStream@526d542f 130 131 // 很多人搞不清输入流和输出流，！！！！ 132 // 其实啊，输入流、输出流都是针对内存的 133 // 往内存里写，是输入流。 134 // 内存往文件里写，是输出Luis。 135 // 136 // 比如一个文件A复制到另一文件B，那么，先写到内存里，再写到文件B。 137 // => 则文件A写到内存里，叫输入流。 138 // => 则内存里写到文件B，叫输出流 139 140 141 for (Path dir : dirs) {//for星型循环，即将dirs是Path对象数组，一一传给Path dir 142 // dirs=Path[7] 143 // dirs是[file:/D:/data/73/2012-09-17 144 // , file:/D:/data/73/2012-09-18 145 // , file:/D:/data/73/2012-09-19 146 // , file:/D:/data/73/2012-09-20 147 // , file:/D:/data/73/2012-09-21 148 // , file:/D:/data/73/2012-09-22 149 // , file:/D:/data/73/2012-09-23] 150 151 // dir= Path 152 // 先传，dir是file:/D:/data/73/2012-09-17 153 // 再传，file:/D:/data/73/2012-09-18 154 // 再传，file:/D:/data/73/2012-09-19 155 // 再传，file:/D:/data/73/2012-09-20 156 // 再传，file:/D:/data/73/2012-09-21 157 // 再传，file:/D:/data/73/2012-09-22 158 // 再传，file:/D:/data/73/2012-09-23 159 160 String fileName = dir.getName().replace("-", "");//文件名称 161 // 先获取到如2012-09-17，然后经过replace("-", "")，得到20120917 162 // 再获取，20120918 163 // 再获取，20120919 164 // 再获取，20120920 165 // 再获取，20120921 166 // 再获取，20120922 167 // 再获取，20120923 168 169 //只接受日期目录下的.txt文件，^匹配输入字符串的开始位置,$匹配输入字符串的结束位置,*匹配0个或多个字符。 170 FileStatus[] localStatus = local.globStatus(new Path(dir+"/*"),new RegexAcceptPathFilter("^.*txt$")); 171 // 先获取到，localStatus=FileStatus[23] 172 // localStatus是[DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-17/ars10767@20120917000000.txt; isDirectory=false; length=1111961; replication=1; blocksize=33554432; modification_time=1398669214000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-17/ars10767@20120917001500.txt; isDirectory=false; length=782533; replication=1; blocksize=33554432; modification_time=1398669214000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-17/ars10767@20120917003000.txt; isDirectory=false; length=593507; replication=1; blocksize=33554432; modification_time=1398669214000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-17/ars10767@20120917004500.txt; isDirectory=false; length=839019; replication=1; blocksize=33554432; modification_time=1398669214000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-17/ars10767@20120917010000.txt; isDirectory=false; length=866393; replication=1; blocksize=33554432; modification_time=1398669214000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-17/ars10767@20120917011500.txt; isDirectory=false; length=678491; replication=1; blocksize=33554432; modification_time=1398669214000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-17/ars10767@20120917013000.txt; isDirectory=false; length=593292; replication=1; blocksize=33554432; modification_time=1398669214000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-17/ars10767@20120917014500.txt; isDirectory=false; length=688620; replication=1; blocksize=33554432; modification_time=1398669214000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-17/ars10767@20120917020000.txt; isDirectory=false; length=674864; replication=1; blocksize=33554432; modification_time=1398669214000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-17/ars10767@20120917021500.txt; isDirectory=false; length=635052; replication=1; blocksize=33554432; modification_time=1398669214000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-17/ars10767@20120917023000.txt; isDirectory=false; length=547324; replication=1; blocksize=33554432; modification_time=1398669214000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-17/ars10767@20120917024500.txt; isDirectory=false; length=598814; replication=1; blocksize=33554432; modification_time=1398669214000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-17/ars10767@20120917030000.txt; isDirectory=false; length=542600; replication=1; blocksize=33554432; modification_time=1398669214000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-17/ars10767@20120917031500.txt; isDirectory=false; length=535446; replication=1; blocksize=33554432; modification_time=1398669214000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-17/ars10767@20120917033000.txt; isDirectory=false; length=592780; replication=1; blocksize=33554432; modification_time=1398669214000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-17/ars10767@20120917034500.txt; isDirectory=false; length=619410; replication=1; blocksize=33554432; modification_time=1398669216000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-17/ars10767@20120917040000.txt; isDirectory=false; length=590326; replication=1; blocksize=33554432; modification_time=1398669214000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-17/ars10767@20120917041500.txt; isDirectory=false; length=428487; replication=1; blocksize=33554432; modification_time=1398669214000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-17/ars10767@20120917043000.txt; isDirectory=false; length=598048; replication=1; blocksize=33554432; modification_time=1398669214000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-17/ars10767@20120917044500.txt; isDirectory=false; length=598792; replication=1; blocksize=33554432; modification_time=1398669216000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-17/ars10767@20120917050000.txt; isDirectory=false; length=575613; replication=1; blocksize=33554432; modification_time=1398669214000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-17/ars10767@20120917051500.txt; isDirectory=false; length=619080; replication=1; blocksize=33554432; modification_time=1398669214000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-17/ars10767@20120917053000.txt; isDirectory=false; length=587763; replication=1; blocksize=33554432; modification_time=1398669214000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}] 173 // 再获取到，localStatus=FileStatus[23] 174 // localStatus是[DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-18/ars10767@20120918131500.txt; isDirectory=false; length=1722797; replication=1; blocksize=33554432; modification_time=1398669244000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-18/ars10767@20120918133000.txt; isDirectory=false; length=1922955; replication=1; blocksize=33554432; modification_time=1398669244000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-18/ars10767@20120918134500.txt; isDirectory=false; length=1388036; replication=1; blocksize=33554432; modification_time=1398669244000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-18/ars10767@20120918140000.txt; isDirectory=false; length=1888871; replication=1; blocksize=33554432; modification_time=1398669244000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-18/ars10767@20120918141500.txt; isDirectory=false; length=1685719; replication=1; blocksize=33554432; modification_time=1398669244000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-18/ars10767@20120918143000.txt; isDirectory=false; length=1541381; replication=1; blocksize=33554432; modification_time=1398669244000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-18/ars10767@20120918144500.txt; isDirectory=false; length=1723638; replication=1; blocksize=33554432; modification_time=1398669244000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-18/ars10767@20120918150000.txt; isDirectory=false; length=1629322; replication=1; blocksize=33554432; modification_time=1398669244000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-18/ars10767@20120918151500.txt; isDirectory=false; length=1658684; replication=1; blocksize=33554432; modification_time=1398669244000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-18/ars10767@20120918153000.txt; isDirectory=false; length=1548216; replication=1; blocksize=33554432; modification_time=1398669244000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-18/ars10767@20120918154500.txt; isDirectory=false; length=1510965; replication=1; blocksize=33554432; modification_time=1398669244000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-18/ars10767@20120918160000.txt; isDirectory=false; length=1559078; replication=1; blocksize=33554432; modification_time=1398669244000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-18/ars10767@20120918161500.txt; isDirectory=false; length=1752005; replication=1; blocksize=33554432; modification_time=1398669244000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-18/ars10767@20120918163000.txt; isDirectory=false; length=1901994; replication=1; blocksize=33554432; modification_time=1398669244000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-18/ars10767@20120918164500.txt; isDirectory=false; length=2234304; replication=1; blocksize=33554432; modification_time=1398669244000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-18/ars10767@20120918170000.txt; isDirectory=false; length=1912051; replication=1; blocksize=33554432; modification_time=1398669244000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-18/ars10767@20120918171500.txt; isDirectory=false; length=1711317; replication=1; blocksize=33554432; modification_time=1398669244000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-18/ars10767@20120918173000.txt; isDirectory=false; length=1799747; replication=1; blocksize=33554432; modification_time=1398669244000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-18/ars10767@20120918174500.txt; isDirectory=false; length=2038653; replication=1; blocksize=33554432; modification_time=1398669244000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-18/ars10767@20120918180000.txt; isDirectory=false; length=2341515; replication=1; blocksize=33554432; modification_time=1398669244000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-18/ars10767@20120918181500.txt; isDirectory=false; length=2396977; replication=1; blocksize=33554432; modification_time=1398669244000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-18/ars10767@20120918183000.txt; isDirectory=false; length=2382769; replication=1; blocksize=33554432; modification_time=1398669244000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}, DeprecatedRawLocalFileStatus{path=file:/D:/data/73/2012-09-18/ars10767@20120918184500.txt; isDirectory=false; length=2709048; replication=1; blocksize=33554432; modification_time=1398669244000; access_time=0; owner=; group=; permission=rw-rw-rw-; isSymlink=false}] 175 // 再获取到,,,,不多赘述。 176 177 178 // FileStatus[] localStatus = local.listStatus(new Path(dir+"/*"),new RegexAcceptPathFilter("^.*txt$"));//试试，看有什么区别？ 179 180 // 如果不设置过滤器，FileInputFormat 会使用一个默认的过滤器来排除隐藏文件。 181 // 如果通过调用 setInputPathFilter()设置了过滤器，它会在默认过滤器的基础上进行过滤。换句话说，自定义的过滤器只能看到非隐藏文件。 182 183 184 //RegexAcceptPathFilter这个方法，我们自己写 185 // RegexAcceptPathFilter来只接收我们需要，即txt格式 186 // 这里，我们还可以只接收别的格式，自己去改，一定要锻炼学会改别人的代码 187 188 189 // 获得如2012-09-17日期目录下的所有文件 190 Path[] listedPaths = FileUtil.stat2Paths(localStatus); 191 // 同样，但是我们，最终是要处理文件里的东西，最终是要转成Path类型，因为Path对象f,它对应着一个文件。 192 193 // 先获取，listedPaths=Path[23] 194 // 先获取2012-09-17下的所有，这个不多赘述啦！ 195 196 // 再获取，listedPaths=Path[23] 197 // listedPaths是[file:/D:/data/73/2012-09-18/ars10767@20120918131500.txt 198 // , file:/D:/data/73/2012-09-18/ars10767@20120918133000.txt 199 // , file:/D:/data/73/2012-09-18/ars10767@20120918134500.txt 200 // , file:/D:/data/73/2012-09-18/ars10767@20120918140000.txt 201 // , file:/D:/data/73/2012-09-18/ars10767@20120918141500.txt 202 // , file:/D:/data/73/2012-09-18/ars10767@20120918143000.txt 203 // , file:/D:/data/73/2012-09-18/ars10767@20120918144500.txt 204 // , file:/D:/data/73/2012-09-18/ars10767@20120918150000.txt 205 // , file:/D:/data/73/2012-09-18/ars10767@20120918151500.txt 206 // , file:/D:/data/73/2012-09-18/ars10767@20120918153000.txt 207 // , file:/D:/data/73/2012-09-18/ars10767@20120918154500.txt 208 // , file:/D:/data/73/2012-09-18/ars10767@20120918160000.txt 209 // , file:/D:/data/73/2012-09-18/ars10767@20120918161500.txt 210 // , file:/D:/data/73/2012-09-18/ars10767@20120918163000.txt 211 // , file:/D:/data/73/2012-09-18/ars10767@20120918164500.txt 212 // , file:/D:/data/73/2012-09-18/ars10767@20120918170000.txt 213 // , file:/D:/data/73/2012-09-18/ars10767@20120918171500.txt 214 // , file:/D:/data/73/2012-09-18/ars10767@20120918173000.txt 215 // , file:/D:/data/73/2012-09-18/ars10767@20120918174500.txt 216 // , file:/D:/data/73/2012-09-18/ars10767@20120918180000.txt 217 // , file:/D:/data/73/2012-09-18/ars10767@20120918181500.txt 218 // , file:/D:/data/73/2012-09-18/ars10767@20120918183000.txt 219 // , file:/D:/data/73/2012-09-18/ars10767@20120918184500.txt] 220 221 //输出路径 222 Path block = new Path("hdfs://djt002:9000/outData/MergeSmallFilesToHDFS/"+ fileName + ".txt"); 223 //fileName是"fileName" 224 // block=Path 225 // block是hdfs://djt002:9000/outData/MergeSmallFilesToHDFS/20120918.txt 226 227 // 打开输出流 228 out = fs.create(block);//因为，合并小文件之后，比如这是，合并2012-09-17日期目录下的所有小文件，之后，要上传到HDFS里。 229 // 类似于，文件A写到内存里，再内存里写到文件B。而这行代码out = fs.create(block);是相当于是，内存里写到文件B。所以是输出流，即是从内存里输出的，所以叫输出流。 230 // 这里，文件A是Local 文件B是HDFS 231 232 // 文件与块大小（比如128M）来比，小的话，称为小文件。是一个相对概念！相对于数据块而言的！ 233 234 // 很多人搞不清输入流和输出流，！！！！ 235 // 其实啊，输入流、输出流都是针对内存的 236 // 往内存里写，是输入流。 237 // 内存往文件里写，是输出Luis。 238 // 239 // 比如一个文件A复制到另一文件B，那么，先写到内存里，再写到文件B。 240 // => 则文件A写到内存里，叫输入流。 241 // => 则内存里写到文件B，叫输出流 242 243 244 for (Path p : listedPaths) {//for星型循环，即将listedPaths的值一一传给Path p 245 //先获取2012-09-17下的所有，这个不多赘述啦！ 246 //现在，获取到2012-09-18下了 247 // p=Path 248 // p是file:/D:/data/73/2012-09-18/ars10767@20120918134500.txt 249 // 得一个一个来，这才叫做一一传给Path p 250 251 in = local.open(p);// 打开输入流in 252 // 类似于，文件A写到内存里，再内存里写到文件B。而这行代码in = local.open(p);是相当于是，文件A写到内存里。所以是输如流，即是写到内存里的，所以叫输入流。 253 // 这里，文件A是Local 文件B是HDFS 254 255 IOUtils.copyBytes(in, out, 4096, false); // 复制数据，IOUtils.copyBytes可以方便地将数据写入到文件，不需要自己去控制缓冲区，也不用自己去循环读取输入源。false表示不自动关闭数据流，那么就手动关闭。 256 // IOUtils.copyBytes这个方法很重要 257 //是否自动关闭输入流和输出流，若是false，就要单独去关闭。则不在这个方法体里关闭输入和输出流了。 258 // 若是true，则在这个方法里关闭输入和输出流。不需单独去关闭了 259 260 261 // 明白，IOUtils类的copyBytes将hdfs数据流拷贝到标准输出流System.out中， 262 // copyBytes前两个参数好理解，一个输入，一个输出，第三个是缓存大小，第四个指定拷贝完毕后是否关闭流。 263 // 要设置为false，标准输出流不关闭，我们要手动关闭输入流。即，设置为false表示关闭输入流 264 265 // 主要是把最后的这个参数定义好， 就可以了。 定义为true还是false，则决定着是否在这个方法体里关闭 266 // 若定义为true,则在这个方法体里直接关闭输入流、输出流。不需单独去关闭了 267 // 若定义为false,则不在这个方法体里直接关闭输入流、输出流。需单独去关闭了 268 269 270 // 关闭输入流 271 in.close();//若定义为false,则不在这个方法体里直接关闭输入流、输出流。需单独去关闭了。这就是单独在关闭输入流！！！懂了吗 272 } 273 if (out != null) {//这里为什么不为空，空指针，则说明里面还有资源。 274 // 关闭输出流 275 out.close();//若定义为false,则不在这个方法体里直接关闭输入流、输出流。需单独去关闭了。这就是单独在关闭输出流！！！懂了吗 276 } 277 } 278 279 } 280 281 /** 282 * 283 * @function 过滤 regex 格式的文件 284 * 285 */ 286 public static class RegexExcludePathFilter implements PathFilter { 287 private final String regex;//变量 288 289 public RegexExcludePathFilter(String regex) {//这个是上面的那个，正在表达式 290 this.regex = regex;//将String regex的值，赋给RegexExcludePathFilter类里的private final String regex的值 291 } 292 293 public boolean accept(Path path) {//主要是实现accept方法 294 // TODO Auto-generated method stub 295 boolean flag = path.toString().matches(regex);//匹配正则表达式，这里是^.*svn$ 296 return !flag; 297 } 298 299 } 300 301 /** 302 * 303 * @function 接受 regex 格式的文件 304 * 305 */ 306 public static class RegexAcceptPathFilter implements PathFilter { 307 private final String regex;//变量 308 309 public RegexAcceptPathFilter(String regex) {//这个是上面的那个，正在表达式 310 this.regex = regex;//将String regex的值，赋给RegexAcceptPathFilter类里的private final String regex的值 311 } 312 313 public boolean accept(Path path) {//主要是实现accept方法 314 // TODO Auto-generated method stub 315 boolean flag = path.toString().matches(regex);//匹配正则表达式,这里是^.*txt$ 316 return flag; 317 } 318 319 } 320 }
本文转自大数据躺过的坑博客园博客，原文链接：http://www.cnblogs.com/zlslch/p/6174553.html，如需转载请自行联系原作者
