Hadoop 3.x（HDFS）----【HDFS 的 API 操作】---- 代码

package com.fickler.hdfs; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.*; import org.apache.hadoop.mapreduce.util.HostUtil; import org.junit.Test; import java.io.IOException; import java.net.URI; import java.net.URISyntaxException; import java.util.Arrays; /** * @author dell * @version 1.0 */ public class HdfsClient { @Test public void testMkdirs() throws URISyntaxException, IOException, InterruptedException { //连接的集群nn地址 URI uri = new URI("hdfs://hadoop102:8020"); //配置文件 Configuration configuration = new Configuration(); //用户 String user = "fickler"; //获得客户端对象 FileSystem fileSystem = FileSystem.get(uri, configuration, user); //创建一个文件夹 fileSystem.mkdirs(new Path("/xiyou/huaguoshan")); //关闭资源 fileSystem.close(); } @Test public void testPut() throws URISyntaxException, IOException, InterruptedException { //连接到集群nn URI uri = new URI("hdfs://hadoop102:8020"); //用户 String user = "fickler"; //配置文件 Configuration configuration = new Configuration(); //获得客户端对象 FileSystem fileSystem = FileSystem.get(uri, configuration, user); //上传文件 //第一个参数：是否删除元数据，第二个参数：是否覆盖写入，第三个参数：元数据路径，第四个参数：拷贝路径 fileSystem.copyFromLocalFile(true, true, new Path("d:/sunwukong.txt"), new Path("/xiyou/huaguoshan")); //关闭资源 fileSystem.close(); } @Test public void testCopyToLocalFile() throws URISyntaxException, IOException, InterruptedException { URI uri = new URI("hdfs://hadoop102:8020"); String user = "fickelr"; Configuration configuration = new Configuration(); FileSystem fileSystem = FileSystem.get(uri, configuration, user); //第一个参数：是否将原文件删除，第二个参数：要下载的文件路径，第三个参数：文件将要下载到的路径，第四个参数：是否开启文件校验 fileSystem.copyToLocalFile(false, new Path("/xiyou/huaguoshan/sunwukong.txt"), new Path("d:/sunwukong.txt"), true); fileSystem.close(); } @Test public void testRename() throws URISyntaxException, IOException, InterruptedException { URI uri = new URI("hdfs://hadoop102:8020"); String user = "fickler"; Configuration configuration = new Configuration(); FileSystem fileSystem = FileSystem.get(uri, configuration, user); fileSystem.rename(new Path("/xiyou/huaguoshan/sunwukong.txt"), new Path("/xiyou/huaguoshan/meihouwang.txt")); fileSystem.close(); } @Test public void testDelete() throws URISyntaxException, IOException, InterruptedException { URI uri = new URI("hdfs://hadoop102:8020"); String user = "fickler"; Configuration configuration = new Configuration(); FileSystem fileSystem = FileSystem.get(uri, configuration, user); //第一个参数：要删除的目录，第二个参数：是否递归删除 fileSystem.delete(new Path("/xiyou"), true); fileSystem.close(); } @Test public void testListFiles() throws URISyntaxException, IOException, InterruptedException { URI uri = new URI("hdfs://hadoop102:8020"); String user = "fickler"; Configuration configuration = new Configuration(); FileSystem fileSystem = FileSystem.get(uri, configuration, user); RemoteIterator<LocatedFileStatus> listFiles = fileSystem.listFiles(new Path("/"), true); while (listFiles.hasNext()) { LocatedFileStatus next = listFiles.next(); System.out.println(next.getPermission()); System.out.println(next.getOwner()); System.out.println(next.getGroup()); System.out.println(next.getLen()); System.out.println(next.getModificationTime()); System.out.println(next.getReplication()); System.out.println(next.getBlockSize()); System.out.println(next.getPath().getName()); //获取块信息 BlockLocation[] blockLocations = next.getBlockLocations(); System.out.println(Arrays.toString(blockLocations)); } fileSystem.close(); } @Test public void testListStatus() throws URISyntaxException, IOException, InterruptedException { URI uri = new URI("hdfs://hadoop102:8020"); String user = "fickler"; Configuration configuration = new Configuration(); FileSystem fileSystem = FileSystem.get(uri, configuration, user); FileStatus[] fileStatuses = fileSystem.listStatus(new Path("/")); for (FileStatus fileStatus : fileStatuses) { if (fileStatus.isFile()) { System.out.println("f:" + fileStatus.getPath().getName()); } else { System.out.println("d:" + fileStatus.getPath().getName()); } } fileSystem.close(); } }