HDFS中JAVA API的使用

package com.hdfs;import java.io.FileInputStream;import java.io.IOException;import java.io.InputStream;import org.apache.hadoop.conf.Configuration;import org.apache.hadoop.fs.FSDataOutputStream;import org.apache.hadoop.fs.FileStatus;import org.apache.hadoop.fs.FileSystem;import org.apache.hadoop.fs.Path;import org.apache.hadoop.io.IOUtils;public class HdfsTest {    //创建新文件  public static void createFile(String dst , byte[] contents) throws IOException{    Configuration conf = new Configuration();    FileSystem fs = FileSystem.get(conf);    Path dstPath = new Path(dst); //目标路径    //打开一个输出流    FSDataOutputStream outputStream = fs.create(dstPath);    outputStream.write(contents);    outputStream.close();    fs.close();    System.out.println("文件创建成功！");  }    //上传本地文件  public static void uploadFile(String src,String dst) throws IOException{    Configuration conf = new Configuration();    FileSystem fs = FileSystem.get(conf);    Path srcPath = new Path(src); //原路径    Path dstPath = new Path(dst); //目标路径    //调用文件系统的文件复制函数,前面参数是指是否删除原文件，true为删除，默认为false    fs.copyFromLocalFile(false,srcPath, dstPath);        //打印文件路径    System.out.println("Upload to "+conf.get("fs.default.name"));    System.out.println("------------list files------------"+"/n");    FileStatus [] fileStatus = fs.listStatus(dstPath);    for (FileStatus file : fileStatus)     {      System.out.println(file.getPath());    }    fs.close();  }    //文件重命名  public static void rename(String oldName,String newName) throws IOException{    Configuration conf = new Configuration();    FileSystem fs = FileSystem.get(conf);    Path oldPath = new Path(oldName);    Path newPath = new Path(newName);    boolean isok = fs.rename(oldPath, newPath);    if(isok){      System.out.println("rename ok!");    }else{      System.out.println("rename failure");    }    fs.close();  }  //删除文件  public static void delete(String filePath) throws IOException{    Configuration conf = new Configuration();    FileSystem fs = FileSystem.get(conf);    Path path = new Path(filePath);    boolean isok = fs.deleteOnExit(path);    if(isok){      System.out.println("delete ok!");    }else{      System.out.println("delete failure");    }    fs.close();  }    //创建目录  public static void mkdir(String path) throws IOException{    Configuration conf = new Configuration();    FileSystem fs = FileSystem.get(conf);    Path srcPath = new Path(path);    boolean isok = fs.mkdirs(srcPath);    if(isok){      System.out.println("create dir ok!");    }else{      System.out.println("create dir failure");    }    fs.close();  }    //读取文件的内容  public static void readFile(String filePath) throws IOException{    Configuration conf = new Configuration();    FileSystem fs = FileSystem.get(conf);    Path srcPath = new Path(filePath);    InputStream in = null;    try {      in = fs.open(srcPath);      IOUtils.copyBytes(in, System.out, 4096, false); //复制到标准输出流    } finally {      IOUtils.closeStream(in);    }  }      public static void main(String[] args) throws IOException {    //测试上传文件    //uploadFile("D://c.txt", "/user/hadoop/test/");    //测试创建文件    /*byte[] contents = "hello world 世界你好/n".getBytes();    createFile("/user/hadoop/test1/d.txt",contents);*/    //测试重命名    //rename("/user/hadoop/test/d.txt", "/user/hadoop/test/dd.txt");    //测试删除文件    //delete("test/dd.txt"); //使用相对路径    //delete("test1");  //删除目录    //测试新建目录    //mkdir("test1");    //测试读取文件    readFile("test1/d.txt");  }}