java多线程读写文件实例

Java多线程读文件：

 package com.myjava;
 import java.io.BufferedReader;
 import java.io.FileNotFoundException;
 import java.io.FileReader;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 public class ThreadReadDemo {

     /**Java多线程读大文件
      * @param args
      */
     public static void main(String[] args) {
         Thread t1=new Thread(new MultiThread(),"A");
         Thread t2=new Thread(new MultiThread(),"B");
         t1.start();
         t2.start();
     }

 }


  class MultiThread implements Runnable{
     private static BufferedReader br = null;
     private List<String> list;

     static{
         try {
             br = new BufferedReader(new FileReader("F://ThreadDemo.txt"),10);
         } catch (FileNotFoundException e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
         }
     }

     public void run() {
         String line = null;
         int count = 0;
         while(true) {
             //System.out.println(Thread.currentThread().getName());
             this.list = new ArrayList<String>();
             synchronized(br) {
                 try {
                     while((line = br.readLine()) != null) {
                         if(count<15) {
                             list.add(line);
                             count++;
                         }else {
                             list.add(line);
                             count = 0;
                             break;
                         }
                     }
                 } catch (IOException e) {
                     e.printStackTrace();
                 }
             }
             try {
                 Thread.sleep(1);
                 display(this.list);
             } catch (InterruptedException e) {
                 e.printStackTrace();
             }
             if(line == null)
                 break;
         }


     }

     public void display(List<String> list) {
         for(String str:list) {
             System.out.println(str);
         }
         System.out.println(list.size());
     }

 }

java多线程写文件：

 package com.myjava;

 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.util.concurrent.ConcurrentLinkedQueue;

 /**
  * 多线程下写文件
  *
  * @author Administrator
  *
  */
 public class ThreadDemo {

     public static void main(String[] args) {
         File file=new File("F:"+File.separator+"ThreadDemo.txt");
         try {
             FileOutputStream out=new FileOutputStream(file, true);
             ConcurrentLinkedQueue<String> queue=new ConcurrentLinkedQueue<String>();
             for(int i=0;i<10;i++){
                 new Thread(new MyThread(queue,"线程"+i+",")).start();//多线程往队列中写入数据
             }
             new Thread(new DealFile(out,queue)).start();//监听线程，不断从queue中读数据写入到文件中
             try {
                 Thread.sleep(3000);
                 if(!Thread.currentThread().isAlive()){
                     System.out.println("线程已结束");
                 }
             } catch (InterruptedException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             }

         } catch (FileNotFoundException e) {
             e.printStackTrace();
         }

     }
 }

 /**
  * 将要写入文件的数据存入队列中
  *
  * @author Administrator
  *
  */
 class MyThread implements Runnable {
     private ConcurrentLinkedQueue<String> queue;
     private String contents;

     public MyThread() {
     }

     public MyThread(ConcurrentLinkedQueue<String> queue, String contents) {
         this.queue = queue;
         this.contents = contents;
     }

     @Override
     public void run() {
         try {
             Thread.sleep(100);
         } catch (InterruptedException e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
         }
         queue.add(contents);
     }
 }
 /**
  * 将队列中的数据写入到文件
  * @author Administrator
  *
  */
 class DealFile implements Runnable {
     private FileOutputStream out;
     private ConcurrentLinkedQueue<String> queue;

     public DealFile() {
     }

     public DealFile(FileOutputStream out, ConcurrentLinkedQueue<String> queue) {
         this.out = out;
         this.queue = queue;
     }

     @Override
     public void run() {
         synchronized (queue) {
             while (true) {
                 if (!queue.isEmpty()) {
                     try {
                         out.write(queue.poll().getBytes("UTF-8"));
                     } catch (IOException e) {
                         // TODO Auto-generated catch block
                         e.printStackTrace();
                     }
                 }
                 try {
                     Thread.sleep(100);
                 } catch (InterruptedException e) {
                     e.printStackTrace();
                 }
             }
         }

     }

 }