HDFS文件系统的使用--java

一、准备jar包

lib下所有jar包和图上所示jar包

二、测试

    @Test
    public void  test()
    {
      //做一个配置    
      Configuration conf=new Configuration();
      //服务器的地址   端口号
      conf.set("fs.defaultFS","hdfs://192.168.1.63:9000");
      try {
        //连接到服务器上去  
        FileSystem fileSystem = FileSystem.get(conf);
        //getFileStatus  获取当前某个路径的状态
        FileStatus fileStatus = fileSystem.getFileStatus(new Path("/zp.txt"));
        System.out.println(fileStatus.isFile()); //是不是一个文件
        System.out.println(fileStatus.isDirectory()); //是不是一个目录
        System.out.println(fileStatus.getPath()); //文件的路径
        System.out.println(fileStatus.getLen()); //文件大小
               fileStatus.close();
      } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    }

三、创建文件夹

@Test
    public void mkdir()
    {
        Configuration conf=new Configuration();
        
            try {
                //连接
                FileSystem fs = FileSystem.get(new URI("hdfs://192.168.1.63:9000"),conf);
                fs.mkdirs(new Path("/user"));
                fs.mkdirs(new Path("/hello/world/bailiban"));
                
                //关闭
                fs.close();
                
            } catch (IOException | URISyntaxException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            
    }

四、文件上传

@Test
    public void upload()
    {
        
        Configuration conf=new Configuration();
        
            try {
                FileSystem fileSystem = FileSystem.get(new URI("hdfs://192.168.1.63:9000"),conf);
                FSDataOutputStream out = fileSystem.create(new Path("/hadoop-2.7.7.tar"));
                FileInputStream in=new FileInputStream(new File("D:\\Hadoop\\hadoop-2.7.7.tar"));
                byte[]b=new byte[1024];
                int len=0;
                while((len=in.read(b))!=-1)
                {
                    out.write(b,0,len);
                }
                in.close();
                out.close();
            } catch (IOException | URISyntaxException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        
    }

五、文件下载

@Test
    public void download()
    {
        Configuration conf=new Configuration();
        try {
            FileSystem fileSystem = FileSystem.get(new URI("hdfs://192.168.1.63:9000"),conf);
            FSDataInputStream in = fileSystem.open(new Path("/zp.txt")); 
            //流的概念
            //输入流  输出流
            FileOutputStream out=new FileOutputStream(new File("D://Hadoop//zp.txt"));
            byte[]b=new byte[1024];
            int len=0;
            while((len=in.read(b))!=-1)
            {
                out.write(b, 0, len);
            }
            in.close();
            out.close();
            
        } catch (IOException | URISyntaxException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    
    }

六、重命名

@Test
    public void mv()
    {
        Configuration conf=new Configuration();
        
            try {
                //连接
                FileSystem fileSystem = FileSystem.get(new URI("hdfs://192.168.1.63:9000"),conf);
                boolean rename = fileSystem.rename(new Path("/hadoop-2.7.7.tar.gz"),new Path("/hadoop.tar.gz"));
                System.out.println(rename?"修改成功":"修改失败");
                //关闭
                fileSystem.close();
                
            } catch (IOException | URISyntaxException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            
    }

七、递归查看文件夹

@Test 
public void ls() {
    Configuration conf = new Configuration();
    conf.set("fs.defaultFS", "hdfs://192.168.1.63:9000");
    try {
        FileSystem fs = FileSystem.get(conf);
        FileStatus[] fls = fs.listStatus(new Path("/"));
        for(FileStatus fst:fls) {
            judge(fs,fst);
        }
        fs.close();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

public void list(FileSystem fs,FileStatus fst) {
    String name = fst.getPath().toString().split("hdfs://192.168.1.63:9000/")[1];
    if(fst.isDirectory()) {
        System.out.println("d: "+name);
        try {
            FileStatus[] fls = fs.listStatus(new Path("/"+name));
            for(FileStatus fst2:fls) {
                list(fs,fst2);
            }
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }else {
        System.out.println("f: "+name);
    }
}