java线程

要点：

1、如何创建线程及线程的基本操作

2、可见性及volatile关键字

3、争用条件

4、线程的互斥synchronized

5、线程的同步wait/notify/notifyall

参见：慕课网《深入浅出java多线程》例子

package com.www.concurrent.base;public class ArmyRunnable implements Runnable {//可见性 ref JVMvolatile boolean keepRunning=true;@Overridepublic void run() {// TODO Auto-generated method stubwhile (keepRunning) {for (int i = 0; i < 5; i++) {System.out.println(Thread.currentThread().getName()+"进攻对方5连击"+"["+i+"]");Thread.yield();}}System.out.println(Thread.currentThread().getName()+"结束了战斗！");}}

package com.www.concurrent.base;public class KeyPersonThread extends Thread {public void run(){System.out.println(Thread.currentThread().getName()+"开始了战斗");for (int i = 0; i < 10; i++) {System.out.println(Thread.currentThread().getName()+"昨突右杀，攻击隋军");}System.out.println(Thread.currentThread().getName()+"结束了战斗！");}}

package com.www.concurrent.base;public class Stage extends Thread {public void run(){System.out.println("欢迎观看隋唐演义");try {Thread.sleep(5000);} catch (InterruptedException e1) {// TODO Auto-generated catch blocke1.printStackTrace();}System.out.println("大幕徐徐拉开");try {Thread.sleep(5000);} catch (InterruptedException e1) {// TODO Auto-generated catch blocke1.printStackTrace();}System.out.println("话说隋朝末年，隋军与农民起义军杀的昏天黑地。。。");ArmyRunnable armyTaskOfSuiDynasty=new ArmyRunnable();ArmyRunnable armyTaskOfRevolt=new ArmyRunnable();Thread armyOfSuiDynasty =new Thread(armyTaskOfSuiDynasty, "隋军");Thread armyOfRevolt=new Thread(armyTaskOfRevolt,"农民起义军");armyOfSuiDynasty.start();armyOfRevolt.start();try {Thread.sleep(500);} catch (InterruptedException e) {// TODO Auto-generated catch blocke.printStackTrace();}armyTaskOfSuiDynasty.keepRunning=false;armyTaskOfRevolt.keepRunning=false;System.out.println("正当双方激战正酣，半路杀出了个程咬金");Thread mrCheng=new KeyPersonThread();mrCheng.setName("程咬金");System.out.println("程咬金的理想是结束战争，使百姓安居乐业！");//armyTaskOfSuiDynasty.keepRunning=false;//armyTaskOfRevolt.keepRunning=false;try {Thread.sleep(2000);} catch (InterruptedException e) {// TODO Auto-generated catch blocke.printStackTrace();}mrCheng.start();try {mrCheng.join();} catch (InterruptedException e) {// TODO Auto-generated catch blocke.printStackTrace();}System.out.println("结束战争，百姓安居乐业,程咬金实现了积极的人生理想");System.out.println("谢谢观看隋唐演义，再见！");}public static void main(String[] args){new Stage().start();}}

package com.www.Enery;/** * 宇宙的能量系统 * 遵循能量守恒定律： * 能量不会凭空创生或消失，只会从一处转移到另一处 */public class EnergySystem {//能量盒子，能量存贮的地方 private final double[] energyBoxes; private final Object lockObj = new Object();  /**  *   * @param n    能量盒子的数量  * @param initialEnergy 每个能量盒子初始含有的能量值  */ public EnergySystem(int n, double initialEnergy){ energyBoxes = new double[n]; for (int i = 0; i < energyBoxes.length; i++) energyBoxes[i] = initialEnergy; }  /**  * 能量的转移，从一个盒子到另一个盒子  * @param from 能量源  * @param to     能量终点   * @param amount 能量值  */ public void transfer(int from, int to, double amount){  synchronized(lockObj){ // if (energyBoxes[from] < amount)// return;//while循环，保证条件不满足时任务都会被条件阻挡 //而不是继续竞争CPU资源 while (energyBoxes[from] < amount){ try {//条件不满足, 将当前线程放入Wait SetlockObj.wait();} catch (InterruptedException e) {e.printStackTrace();} }   System.out.print(Thread.currentThread().getName()); energyBoxes[from] -= amount; System.out.printf("从%d转移%10.2f单位能量到%d", from, amount, to); energyBoxes[to] += amount; System.out.printf(" 能量总和：%10.2f%n", getTotalEnergies());//唤醒所有在lockObj对象上等待的线程 lockObj.notifyAll(); }  }  /**  * 获取能量世界的能量总和   */ public double getTotalEnergies(){ double sum = 0; for (double amount : energyBoxes) sum += amount; return sum; }  /**  * 返回能量盒子的长度  */ public  int getBoxAmount(){ return energyBoxes.length; } }

package com.www.Enery;public class EnergyTransferTask implements Runnable{//共享的能量世界private EnergySystem energySystem;//能量转移的源能量盒子下标private int fromBox;//单次能量转移最大单元private double maxAmount;//最大休眠时间（毫秒）private int DELAY = 10;public EnergyTransferTask(EnergySystem energySystem, int from, double max){this.energySystem = energySystem;this.fromBox = from;this.maxAmount = max;}public void run() {try{while (true){int toBox = (int) (energySystem.getBoxAmount()* Math.random());double amount = maxAmount * Math.random();energySystem.transfer(fromBox, toBox, amount);Thread.sleep((int) (DELAY * Math.random()));}}catch (InterruptedException e){e.printStackTrace();}}}

package com.www.Enery;public class EnergySystemTest {//将要构建的能量世界中能量盒子数量public static final int BOX_AMOUNT = 100;//每个盒子初始能量    public static final double INITIAL_ENERGY = 1000;    public static void main(String[] args){    EnergySystem eng = new EnergySystem(BOX_AMOUNT, INITIAL_ENERGY);    for (int i = 0; i < BOX_AMOUNT; i++){    EnergyTransferTask task = new EnergyTransferTask(eng, i, INITIAL_ENERGY);    Thread t = new Thread(task,"TransferThread_"+i);    t.start();    }    }}