2021 10 6

java操作HDFS：

 

public void set(FileSystem fs)
{
    // 1.新建目录
    Path path = new Path("/user/hadoop/hello");
    try {
        if (!fs.exists(path)){
            fs.mkdirs(path);
        }else{
            System.out.println("路径已存在");
        }
    } catch (IOException e) {
        e.printStackTrace();
    }
}

public static void logup(FileSystem fs,String path,String name)
{
    try {
        if(fs.exists(new Path("/user/hadoop/text/"+name))){
            System.out.println(name + " 文件存在");
            int Temp=0;
            System.out.println("请选择追加或覆盖：1、追加 2、覆盖");
            Path path1 = new Path("/user/hadoop/text/"+name);
            FSDataInputStream getIt = fs.open(path1);
            BufferedReader dA = new BufferedReader(new FileReader(path));
            BufferedReader dB = new BufferedReader(new InputStreamReader(getIt));
            String contentA = dA.readLine(); //读取文件一行
            String contentB = dB.readLine();
            String mem = new String();
            mem = contentB+contentA;
            if(Temp==2) mem=contentA;
            FSDataOutputStream os = fs.create(path1);
            os.writeUTF(mem);
            os.close();
            dA.close(); //关闭文件A
            dB.close(); //关闭文件B

        }else{
            System.out.println(name + " 文件不存在");
            fs.copyFromLocalFile(new Path("D:\\sean.txt"),
                    new Path("/user/hadoop/text/sean.txt"));
        }

        fs.close();
    } catch (IOException e) {
        e.printStackTrace();
    }
}