多線程順序打印

前言：

      下面的代碼是參考網址：http://love3400wind.blog.163.com/blog/static/796308012013117102941831/ , http://blog.csdn.net/liu251/article/details/6227763 做了一點點的改動。

      感謝兩位作者！

題目：

有A,B,C三個線程, A線程輸出A, B線程輸出B, C線程輸出C

要求, 同時啟動三個線程, 按順序輸出ABC, 循環10次

 

核心要素：

     1，工作線程對象之間的關聯。

     2，工作線程的狀態修改(前一個線程對象有能力修改后一個線程對象的狀態)。

 

示例：

package org.wit.ff.thread;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

/**
 * 
 * @author F.Fang
 * 
 */
public class ABCDemo {

    private Lock lock = new ReentrantLock();// 通過JDK5中的鎖來保證線程的訪問的互斥
    private Condition condition = lock.newCondition();// 線程協作

    public static void main(String[] args) {
        ABCDemo abc = new ABCDemo();

        // 使用循環可以不局限於只有3個線程 交替, 任意多個都可以.
        PrintThread a = abc.new PrintThread("A", true);
        PrintThread b = abc.new PrintThread("B", false);
        PrintThread c = abc.new PrintThread("C", false);

        a.setNext(b);
        b.setNext(c);
        c.setNext(a);

        ExecutorService executor = Executors.newFixedThreadPool(3);// 通過線程池執行
        for (int i = 0; i < 3; i++) {
            executor.execute(a);
            executor.execute(b);
            executor.execute(c);
        }
        executor.shutdown();//關閉線程池
    }

    class PrintThread implements Runnable {
        private String name;

        private PrintThread next;

        private boolean execute;

        public PrintThread(String name, boolean execute) {
            this.name = name;
            this.execute = execute;
        }

        public PrintThread(String name, PrintThread next, boolean execute) {
            this.name = name;
            this.next = next;
            this.execute = execute;
        }

        public void run() {
            lock.lock();
            try {
                while (true) {

                    if (execute) {
                        // 執行當前業務
                        print();
                        // 當前任務執行完成后 改變執行狀態為false
                        execute = false;
                        // 將下一個相鄰任務狀態設置為true
                        next.setExecute(true);
                        try {
                            Thread.sleep(100);
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                        // 通知其它任務.
                        condition.signalAll();
                        break;
                    } else {
                        try {
                            // 若非執行狀態 即等待.
                            condition.await();
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                    }
                }
            } finally {
                lock.unlock();
            }
        }

        public void print() {
            System.out.println(name);
        }

        public void setExecute(boolean execute) {
            this.execute = execute;
        }

        public void setNext(PrintThread next) {
            this.next = next;
        }

    }

}