大数据实验两个文件分别是有序的数，上传到HDFS读出来排序，写回到HDFS 的新的文件

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataInputStream;

import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;


import java.io.BufferedReader;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URI;

public class Demo {
	static int[] array = new int[80];
	static int[] array2 = new int[40];
	static int[] array3 = new int[88];
	public static int[] mergeSortedArray(int[] A, int[] B) {
        // Write your code here
        if(A.length==0)
			return B;
		if(B.length==0)
			return A;
		int []C=new int[A.length+B.length];
		int i=0;//A
		int j=0;//B
		int k=0;//C
		while(i<A.length&&j<B.length){
			if(A[i]>B[j]){
				C[k++]=B[j++];
			}else{
				C[k++]=A[i++];
			}
		}
		while(i<A.length){
			C[k++]=A[i++];
		}
		while(j<B.length){
			C[k++]=B[j++];
		}
		return C;
 
    }

 
	public static void main(String[] args) {
		try {
			String filename = \"hdfs://localhost:9000/input/3.txt\";
			String filename2 = \"hdfs://localhost:9000/input/4.txt\";
			Configuration conf = new Configuration();
			FileSystem fs = FileSystem.get(conf);
			FileSystem fs2 = FileSystem.get(conf);
			if (fs.exists(new Path(filename))&&fs2.exists(new Path(filename2))) {
				System.out.println(\"文件存在\");
				 try {
					 Path filePath=new Path(filename);
					 Path filePath2=new Path(filename2);
					 	
					 fs=FileSystem.get(URI.create(filename),conf);
					 fs2=FileSystem.get(URI.create(filename2),conf);	
					 if(fs.exists(filePath)){ 
						 String charset=\"UTF-8\"; 
						 //打开文件数据输入流 
						 FSDataInputStream fsDataInputStream=fs.open(filePath); 
						 //创建文件输入 
						 InputStreamReader inputStreamReader=new InputStreamReader(fsDataInputStream,charset);
						 String line=null; 
						 //把数据读入到缓冲区中
						 BufferedReader reader=null;
						 reader=new BufferedReader(inputStreamReader); 
						 //从缓冲区中读取数据 
						 while((line=reader.readLine())!=null)
						 {
							 System.out.println(\"line=\"+line); 
							 String [] arr = line.split(\"\\\\s+\");
							 
							 int[] intarr = new int[arr.length];
							 for (int i = 0; i < arr.length; i++) 
							 { 
								 intarr[i] = Integer.parseInt(arr[i]);
							 //substring是找出包含起始位置，不包含结束位置，到结束位置的前一位的子串 } 
							 	//输出数组arr
							 		System.out.print(intarr[i]+\" \");
							 }	
							 array=intarr;
						 
						 } 				 
					 } 
					 if(fs2.exists(filePath2)){  
						 String charset=\"UTF-8\"; 
						 //打开文件数据输入流 
						 FSDataInputStream fsDataInputStream=fs.open(filePath2); 
						 //创建文件输入 
						 InputStreamReader inputStreamReader=new InputStreamReader(fsDataInputStream,charset);
						 String line=null; 
						 //把数据读入到缓冲区中
						 BufferedReader reader=null;
						 reader=new BufferedReader(inputStreamReader); 
						 //从缓冲区中读取数据 
						 while((line=reader.readLine())!=null)
						 {
							 System.out.println(\"line=\"+line); 
							 String [] arr2 = line.split(\"\\\\s+\");
							 int[] intarr2 = new int[arr2.length];
							 for (int i = 0; i < arr2.length; i++) 
							 { 
								 intarr2[i] = Integer.parseInt(arr2[i]);
							 //substring是找出包含起始位置，不包含结束位置，到结束位置的前一位的子串 } 
							 	//输出数组
							 		System.out.print(intarr2[i]+\" \");
							 }
							 array2=intarr2;
							/* for(String ss : arr2){
								    System.out.println(ss);
								}*/
							 /*int[] arr2= {12};
							 for(int i=0;i<arr.length;i++){
							     arr2[i]=Integer.parseInt(arr[i]);
							     System.out.println(arr2[i]);
							 }*/
							 
						 } 		
						 
					 } 
		
			
				//合并并且排序
				array3 =mergeSortedArray(array,array2);
			
				//生成5.txt
				File file = new File(\"/home/hadoop/5.txt\");
				FileWriter out = new FileWriter(file);
				for(int i=0;i<array3.length;i++) {
					out.write(array3[i]+\"\\t\");
					System.out.println(array3[i]);
				}
				out.close();
				
				//上传文件
					 try{
						 Path localPath = new Path(\"/home/hadoop/5.txt\"); 
						 Path hdfsPath = new Path(\"hdfs://localhost:9000/input/5.txt\");
						 FileSystem hdfs = FileSystem.get(conf);
						 hdfs.copyFromLocalFile(localPath, hdfsPath);
					 }catch(Exception e){
						 e.printStackTrace(); 
						 } 
					 }
							 
				 catch (IOException e) 
				 { e.printStackTrace();
				 }
				
				 

			} else {
				System.out.println(\"文件不存在\");
			}
			
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
}

//格式化文件，
//./bin/hadoop namenode -format
//启动 结束时要关比，不然数据节点不起动
//./sbin/start-dfs.sh
//创建文件夹input
//./bin/hadoop fs -mkdir /input
//查看文件夹input(是空的)
//./bin/hdfs dfs -ls /input
//上传文件到input
//./bin/hadoop fs -put  /home/hadoop/3.txt   /input
//./bin/hadoop fs -put  /home/hadoop/4.txt   /input
//运行这个java代码，生成5.txt