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();
				}
			}
		}

	}

}