编写Java代码对HDFS进行增删改查操作代码实例

这篇文章主要介绍了Java代码对HDFS进行增删改查操作，文中通过示例代码介绍的非常详细，对大家的学习或者工作具有一定的参考学习价值，需要的朋友们下面随着小编来一起学习学习吧

本文实例为大家分享了Java代码对HDFS进行增删改查操作的具体代码，供大家参考，具体内容如下

import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.net.URI; import org.apache.commons.compress.utils.IoUtils; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.BlockLocation; import org.apache.hadoop.fs.FSDataInputStream; import org.apache.hadoop.fs.FSDataOutputStream; import org.apache.hadoop.fs.FileStatus; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.Path; public class FileOpreation { public static void main(String[] args) throws IOException { //CreateFile(); //DeleteFile(); //copyFiletoHDFS(); //MkDirs(); //DelDirs(); ListDirectory(); DownLoad(); } public static void CreateFile() throws IOException { String uri = "hdfs://Alvis:9000"; Configuration configuration =new Configuration(); FileSystem fSystem = FileSystem.get(URI.create(uri), configuration); byte[] file_content_buff="hello hadoop world, test write file !n".getBytes(); Path dfs = new Path("/home/test.txt"); FSDataOutputStream outputStream = fSystem.create(dfs); outputStream.write(file_content_buff.length); } public FileOpreation() { // Todo Auto-generated constructor stub }public static void DeleteFile() throws IOException { String uri = "hdfs://Alvis:9000"; Configuration configuration =new Configuration(); FileSystem fSystem = FileSystem.get(URI.create(uri), configuration); Path deletf = new Path("/home/test.txt"); boolean delResult = fSystem.delete(deletf,true); System.out.println(delResult==true?"删除成功":"删除失败"); } public static void copyFiletoHDFS() throws IOException { String uri = "hdfs://Alvis:9000"; Configuration configuration =new Configuration(); FileSystem fSystem = FileSystem.get(URI.create(uri), configuration); Path src = new Path("E:\SerializationTest\APITest.txt"); Path dest_src = new Path("/home"); fSystem.copyFromLocalFile(src, dest_src); } public static void MkDirs() throws IOException { String uri = "hdfs://Alvis:9000"; Configuration configuration =new Configuration(); FileSystem fSystem = FileSystem.get(URI.create(uri), configuration); Path src = new Path("/Test"); fSystem.mkdirs(src); } public static void DelDirs() throws IOException { String uri = "hdfs://Alvis:9000"; Configuration configuration = new Configuration(); FileSystem fSystem = FileSystem.get(URI.create(uri), configuration); Path src = new Path("/Test"); fSystem.delete(src); } public static void ListDirectory() throws IOException { String uri = "hdfs://Alvis:9000"; Configuration configuration = new Configuration(); FileSystem fSystem = FileSystem.get(URI.create(uri), configuration); FileStatus[] fStatus = fSystem.listStatus(new Path("/output")); for(FileStatus status : fStatus) if (status.isFile()) { System.out.println("文件路径："+status.getPath().toString()); System.out.println("文件路径 getReplication："+status.getReplication()); System.out.println("文件路径 getBlockSize:"+status.getBlockSize()); BlockLocation[] blockLocations = fSystem.getFileBlockLocations(status, 0, status.getBlockSize()); for(BlockLocation location : blockLocations){ System.out.println("主机名："+location.getHosts()[0]); System.out.println("主机名："+location.getNames()[0]); } } else { System.out.println("directory:"+status.getPath().toString()); } } public static void DownLoad() throws IOException { Configuration configuration = new Configuration(); configuration.set("fs.defaultFS", "hdfs://Alvis:9000"); FileSystem fSystem =FileSystem.get(configuration); FSDataInputStream inputStream =fSystem.open( new Path("/input/wc.jar")); FileOutputStream outputStream = new FileOutputStream(new File("E:\LearnLife\DownLoad\wc.jar")); IoUtils.copy(inputStream, outputStream); System.out.println("下载成功！"); } }

思想：

一、定义虚拟机接口

二、先拿到HDFS远程调用接口对象Configuration

三、定义分布式文件系统FileSystem对象获取对象

四、给定路径

五、用FileSystem对象调用操作

以上所述是小编给大家介绍的Java代码对HDFS进行增删改查操作详解整合，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对编程之家网站的支持！