HDFS Java 客户端开发（开发环境：Windows）

package com.looc.client;

import java.io.FileNotFoundException;
import java.io.IOException;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.LocatedFileStatus;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.RemoteIterator;
import org.junit.Before;
import org.junit.Test;

public class HDFSClient {

private FileSystem fileSystem = null;

@Before
public void getFileSystem() throws IOException {
// 配置参数的封装对象
// 构造函数对xxx-site.xml文件进行解析，真实项目中需要将xxx-site.xml文件加载到工程中。
Configuration configuration = new Configuration();
configuration.set("fs.defaultFS", "hdfs://looc:9000");
// 获取文件系统的客户端实例对象，根据configuration中的相关参数决定。
fileSystem = FileSystem.get(configuration);
}

/**
* 创建文件夹
*
* @throws IllegalArgumentException
* @throws IOException
*/
@Test
public void testMkdir() throws IllegalArgumentException, IOException {
fileSystem.mkdirs(new Path("/a/b/c"));
}

/**
* 上传文件
*
* @throws IllegalArgumentException
* @throws IOException
*/
@Test
public void testUpload() throws IllegalArgumentException, IOException {
fileSystem.copyFromLocalFile(new Path("E:\\MapReduce\\WordCount.txt"), new Path("/a/b/c"));
}

/**
* 重命名文件
*
* @throws IllegalArgumentException
* @throws IOException
*/
@Test
public void testRename() throws IllegalArgumentException, IOException {
fileSystem.rename(new Path("/a/b/c/WordCount.txt"), new Path("/a/b/c/WordCount.txt.rename"));
}

/**
* 下载文件
*
* @throws IllegalArgumentException
* @throws IOException
*/
@Test
public void testDownload() throws IllegalArgumentException, IOException {
fileSystem.copyToLocalFile(new Path("/a/b/c/WordCount.txt.rename"), new Path("E:\\MapReduce"));
}

/**
* 删除文件
*
* @throws IllegalArgumentException
* @throws IOException
*/
@Test
public void testRmfile() throws IllegalArgumentException, IOException {
boolean result = fileSystem.delete(new Path("/a/b/c/WordCount.txt.rename"), true);
System.out.println(result ? "DELETE IS SUCCESSFULLY!" : "DELETE IS FAILD!");
}

/**
* 列举所有文件
*
* @throws FileNotFoundException
* @throws IllegalArgumentException
* @throws IOException
*/
@Test
public void testListFile() throws FileNotFoundException, IllegalArgumentException, IOException {
RemoteIterator<LocatedFileStatus> listFiles = fileSystem.listFiles(new Path("/"), true);
while (listFiles.hasNext()) {
System.out.println(listFiles.next().getPath().getName());
}
}

}

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