从HDFS中下载指定文件,如果本地文件与要下载的文件名称相同,则自动对下载的文件重命名。

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.*;
import org.apache.hadoop.fs.FileSystem;
import java.io.*;

public class B_DownLoadFile {
    public static void copyToLocal(FileSystem fs, Path p_LocalPath,
            Path p_RemotePath, String s_LocalPath, String s_RemotePath) {
        try {
            File f = new File(s_LocalPath);
            Integer i = Integer.valueOf(0);
            while (f.exists()) {
                i++;
                Integer lasti=Integer.valueOf(i-1);
                String[] split_path = s_LocalPath.split("/");
                String[] filename = split_path[4].split("\.");

                if(i>1){
                    filename[0]=filename[0].replace("("+lasti+")", "");
                    System.out.println(filename[0] + "("
                            + lasti.toString() + ")" +"."+ filename[1] + " existed.");
                }
                else
                    System.out.println(filename[0] +"."+ filename[1] + " existed.");
                s_LocalPath = "/"+split_path[1] + "/" + split_path[2] + "/"
                        + split_path[3] + "/" +filename[0] + "("
                        + i.toString() + ")" +"."+ filename[1];
                f = new File(s_LocalPath);
            }
            System.out.println("Download to " + s_LocalPath);
            p_LocalPath = new Path(s_LocalPath);
            fs.copyToLocalFile(p_RemotePath, p_LocalPath);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        Var_init var = new Var_init();
        try {
            B_DownLoadFile.copyToLocal(var.fs, var.p_localFilePath,
                    var.p_remoteFilePath, var.s_localFilePath,
                    var.s_remoteFilePath);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

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