编程实现hdfs对文件的操作

课堂测试1

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package hadoop;

import java.io.*;
 
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.*;
 
 
public class hdfs {
    //路径是否存在
    public static boolean test(Configuration conf,String path) throws  IOException
    {
        FileSystem fs=FileSystem.get(conf);
        return fs.exists(new Path(path));
    }
    //创建目录
    public static boolean mkdir (Configuration conf ,String remoteDir)throws IOException
    {
    FileSystem fs=FileSystem.get(conf);
    Path dirPath=new Path(remoteDir);
    boolean result=fs.mkdirs(dirPath);
    fs.close();
    return result;
    }
    //创建文件
    public static void touchz(Configuration conf,String remoteFilePath )throws IOException
    {
        FileSystem fs=FileSystem.get(conf);
        Path remotePath=new Path(remoteFilePath);
        FSDataOutputStream outputStream =fs.create(remotePath);
        outputStream.close();
        fs.close();
    }
    //删除文件
    public static boolean rm(Configuration conf,String remoteFilePath)throws IOException
    {
        FileSystem fs=FileSystem.get(conf);
        Path remotePath=new Path(remoteFilePath);
        boolean result=fs.delete(remotePath,false);
        fs.close();
        return result;
    }
    //读文件
    public static void cat(Configuration conf,String FilePath)throws IOException
    {
        FileSystem fs=FileSystem.get(conf);
        Path file=new Path(FilePath);
        FSDataInputStream getIt=fs.open(file);
        BufferedReader d=new BufferedReader(new InputStreamReader(getIt));
        String content=d.readLine();
        System.out.println(content);
        d.close();
        fs.close();
    }
    //追加文件内容
    public static void appendContentToFile(Configuration conf,String content,String remoteFilePath)throws IOException
    {
        FileSystem fs=FileSystem.get(conf);
        Path remotePath=new Path(remoteFilePath);
        FSDataOutputStream out=fs.append(remotePath);
        out.write(content.getBytes());
        out.close();
        fs.close();
    }
    //将文件1写入文件2
    public static void appendContentToFile2(Configuration conf,String  remoteFilePath,String remoteFilePath2)throws IOException
    {
        FileSystem fs=FileSystem.get(conf);
        Path file=new Path(remoteFilePath);
        FSDataInputStream  getIt=fs.open(file);
        BufferedReader d=new BufferedReader(new InputStreamReader(getIt));
        String content1=d.readLine();
        
        Path remotePath=new Path(remoteFilePath2);
        FSDataOutputStream out=fs.append(remotePath);
        out.write(content1.getBytes());
        d.close();
        out.close();
        fs.close();
    }
    
    public static void main(String[] args)
    {
        Configuration conf=new Configuration();
        conf.set("dfs.client.block.write.replace-datanode-on-failure.policy","NEVER");
 
        conf.set("dfs.client.block.write.replace-datanode-on-failure.enable","true");
        conf.set("fs.default.name", "hdfs://localhost:9000");
        conf.set("fs.hdfs.impl","org.apache.hadoop.hdfs.DistributedFileSystem");
        String remoteDir ="/user/hadoop/ZMH";//HDFS目录
        String remoteFilePath="/user/hadoop/ZMH/hdfstest1.txt";
        String remoteFilePath2="/user/hadoop/ZMH/hdfstest2.txt";
        String content="赵墨涵课堂测试";
        //创建目录
        try {
            if(!hdfs.test(conf, remoteDir))
            {
                hdfs.mkdir(conf, remoteDir);
                System.out.println("创建目录"+remoteDir);
            }
            else
            {
                System.out.println(remoteDir+"目录已存在");
            }
    //创建文件
            if(!hdfs.test(conf, remoteFilePath))
            {
                hdfs.touchz(conf, remoteFilePath);
                System.out.println("创建文件"+remoteFilePath);
            }
            else
            {
                System.out.println(remoteFilePath+"已存在");
            }
                    //向文件内输入
            hdfs.appendContentToFile(conf, content, remoteFilePath);
            hdfs.cat(conf, remoteFilePath);
            //创建文件2
            if(!hdfs.test(conf, remoteFilePath2))
            {
                hdfs.touchz(conf, remoteFilePath2);
                System.out.println("创建文件"+remoteFilePath2);
            }
            else
            {
                System.out.println(remoteFilePath2+"已存在");
            }
            //向文件2内写入
            hdfs.appendContentToFile2(conf, remoteFilePath, remoteFilePath2);
            hdfs.cat(conf, remoteFilePath2);
        } catch (IOException e) {
        e.printStackTrace();
        }
    }
}