向HDFS中上传任意文本文件,如果指定的文件在HDFS中已经存在,由用户指定是追加到原有文件末尾还是覆盖原有的文件

import java.io.FileInputStream;
import java.io.IOException;
import java.util.Scanner;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;

public class A_UpdatedFile {


    public static void appendToFile(FileSystem fs, String localFilePath,
            String remoteFilePath) {
        Path remotePath = new Path(remoteFilePath);
        try {
            FileInputStream in = new FileInputStream(localFilePath);
            FSDataOutputStream out = fs.append(remotePath);
            byte[] data = new byte[1024];
            int read = -1;
            while ((read = in.read(data)) > 0) {
                out.write(data, 0, read);
            }
            out.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        Var_init var = new Var_init();
        try {
            boolean fileExists = var.fs.exists(var.p_remoteFilePath);
            if (fileExists) {
                System.out.println(var.s_remoteFilePath + " 已存在.");
            } else {
                System.out.println(var.s_remoteFilePath + " 不存在.");
            }
            if (!fileExists) {
                var.fs.copyFromLocalFile(false, true, var.p_localFilePath, var.p_remoteFilePath);
                System.out.println(var.s_localFilePath + " 已上传至 "
                        + var.s_remoteFilePath);
            } else {
                Scanner choose = new Scanner(System.in);
                System.out.println("input c to cover,input a to append");
                String str = choose.next();
                if(str.equals("c"))
                {
                    var.fs.copyFromLocalFile(false, true, var.p_localFilePath, var.p_remoteFilePath);
                    System.out.println("cover successfully");
                }
                else if(str.equals("a"))
                {
                    A_UpdatedFile.appendToFile(var.fs, var.s_localFilePath, var.s_remoteFilePath);
                    System.out.println("append successfully");
                }
                else
                {
                    System.out.println("plz input right common");
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

Var_init类参考  https://www.cnblogs.com/MiraculousB/p/13848744.html