java api针对hdfs,进行创建、上传、下载、重命名、删除文件(练习)

static {
System.setProperty(“hadoop.home.dir”, “E:\x3\hadoop-2.9.2”);
}
public static void main(String[] args) {

  //  FileSystem fs = getHadoopFileSystem();
   //创建文件
   /*boolean result = createPath();
    System.out.print(result);*/
   //上传文件1
  //putFile2HDFS();
    //上传文件2
   // putFile2HDFS2("C:\\Users\\s1378\\Desktop\\kafka.txt","/test44");
    //查询目录
   // list();
    //下载文件
  // getFile2HDFS("/test33/kafka.txt","D:/");
    //下载文件2
   // getFile2HDFS2("/test33/kafka.txt","D:/test.txt");

    //删除
   delFileHDFS("/test1");
}

private static FileSystem getHadoopFileSystem(){
    FileSystem fs = null;
    //根据配置文件创建fs对象
    Configuration conf = new Configuration();
    //放在此处的配置，优先级最高；fs.defaultFS为必须设置的内容
    conf.set("fs.defaultFS","hdfs://sunjunwei.com:9000");

    try {
        fs = FileSystem.get(conf);
    } catch (IOException e) {
        e.printStackTrace();
    }
    return fs;
}

//文件重命名
public static void reName(String oldName,String newName){
FileSystem fs = getFileSystem();

    try {

        fs.rename(new Path(oldName),new Path(newName));
    } catch (IOException e) {
        e.printStackTrace();
    }finally {
        try {
            fs.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}
/**
 * 上传文件
 */
private static void putFile2HDFS(){
    FileSystem fs = getHadoopFileSystem();
    Path localPath = new Path("C:\\Users\\s1378\\Desktop\\kafka.txt");
    //如果路径不存在会创建；如果路径文件已存在，则覆盖
    Path hdfsPath = new Path("/test33/");

    //复制本地文件到HDFS
    try {
        fs.copyFromLocalFile(localPath,hdfsPath);
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        try {
            fs.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}
//上传文件2
private static void putFile2HDFS2(String localPathName,String dstPathName){
    FileSystem fs = getHadoopFileSystem();

    //复制本地文件到HDFS
    try {
        //输入流
        FileInputStream in = new FileInputStream(localPathName);
        //hdfs输出流
        FSDataOutputStream out = fs.create(new Path(dstPathName));
        IOUtils.copyBytes(in,out,4096,true);
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        try {
            fs.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

/**
 * 创建文件夹
 * @return
 */
private static boolean createPath(){
    boolean result = false;
    FileSystem fs = getHadoopFileSystem();
    Path path = new Path("/test33");
    try {
        result = fs.mkdirs(path);
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        try {
            fs.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    return result;
}

/**
 * 列出目录内容
 */
private static void list(){
    FileSystem fs = getHadoopFileSystem();
    Path path = new Path("/");
    try {
        //获取目录详细信息
        FileStatus[] fss = fs.listStatus(path);
        //遍历目录
        for (FileStatus f:fss){
            String isDir = f.isDirectory() ? "目录" : "文件";
            String name = f.getPath().toString();
            System.out.println(isDir+"  "+name);
        }
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        try {
            fs.close();
        } catch (IOException e){
            e.printStackTrace();
        }
    }

}

//下载文件
private static  void getFile2HDFS(String localPathName,String hdfsPathName){
    FileSystem fs = getHadoopFileSystem();


    try {
        fs.copyToLocalFile(new Path(localPathName),new Path(hdfsPathName));
    } catch (IOException e) {
        e.printStackTrace();
    }finally {
        try {
            fs.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

//下载文件2
private static  void getFile2HDFS2(String hdfsPathName,String localPathName){
    FileSystem fs = getHadoopFileSystem();

    try {
        FSDataInputStream open = fs.open(new Path(hdfsPathName));
        FileOutputStream out = new FileOutputStream(localPathName);
        IOUtils.copyBytes(open,out,4096,true);
    } catch (IOException e) {
        e.printStackTrace();
    }finally {
        try {
            fs.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }


}

//删除
private static boolean delFileHDFS(String pathName){
    boolean flag = false;
    FileSystem fs = getHadoopFileSystem();

    try {
        flag = fs.delete(new Path(pathName), true);
    } catch (IOException e) {
        e.printStackTrace();
    }finally {
        try {
            fs.close();
        } catch (IOException e) {
            e.printStackTrace();
        }

        return flag;
    }
}