多线程

基本的概念

 

继承Thread类和Runnable接口对比

 

Lambda表达式

 

 

 

线程状态

 

 

 

 

package com.chen.State;

//观察测试线程的状态
public class TestState {
    public static void main(String[] args) throws InterruptedException {
        Thread thread = new Thread(()->{
            for (int i = 0; i < 5; i++) {
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
            System.out.println("///////");
        });


        //观察状态
        Thread.State state = thread.getState();
        System.out.println(state); //NEW


        //观察启动后
        thread.start();//启动线程
        state = thread.getState();
        System.out.println(state);//RUN


        while (state != Thread.State.TERMINATED ){ //只要线程不终止，就一直输出状态
            Thread.sleep(100);
            state = thread.getState();//更新线程状态
            System.out.println(state);//输出状态
        }

    }
}

 

 线程优先级

package com.chen.State;

//测试程序的优先级
public class TestPriority {
    public static void main(String[] args) {
        //主线程默认优先级
        System.out.println(Thread.currentThread().getName()+"-->"+Thread.currentThread().getPriority());
        MyPriority myPriority = new MyPriority();

        Thread t1 = new Thread(myPriority);
        Thread t2 = new Thread(myPriority);
        Thread t3 = new Thread(myPriority);
        Thread t4 = new Thread(myPriority);
        Thread t5 = new Thread(myPriority);
        Thread t6 = new Thread(myPriority);

        //先设置优先级,再启动
        t1.start();

        t2.setPriority(1);
        t2.start();

        t3.setPriority(4);
        t3.start();

        t4.setPriority(Thread.MAX_PRIORITY);
        t4.start();



    }
}

class MyPriority implements Runnable{
    @Override
    public void run() {
        System.out.println(Thread.currentThread().getName()+"-->"+Thread.currentThread().getPriority());
    }
}

 

 守护线程

package com.chen.State;

//测试守护线程
//上帝守护你
public class TestDaemon {
    public static void main(String[] args) {
        God god = new God();
        You you = new You();

        Thread thread = new Thread(god);
        thread.setDaemon(true); //默认是false表示用户线程,正常的线程都是用户线程
        thread.start();

        new Thread(you).start();//你  用户线程启动...


    }
}


//上帝
class God implements Runnable{
    @Override
    public void run() {
        while (true){
            System.out.println("上帝保佑着你");
        }
    }
}

//你
class You implements Runnable{
    @Override
    public void run() {
        for (int i = 0; i < 36500; i++) {
            System.out.println("你一生都开心地活着");
        }
        System.out.println("========goodbye!world==========");
    }
}


同步方法,同步块

 

 

package com.chen.syn;

//不安全的取钱
//两个人去银行取钱,账户
public class UnsafeBank {
    public static void main(String[] args) {
        //账户
        Account account = new Account(100,"结婚基金");

        Drawing you = new Drawing(account,50,"你");
        Drawing girlFriend = new Drawing(account,100,"girlFriend");

        you.start();
        girlFriend.start();
    }
}


//账户
class Account{
    int money;//余额
    String name;//卡名

    public Account(int money, String name) {
        this.money = money;
        this.name = name;
    }
}

//银行:模拟取款
class  Drawing extends Thread{
    Account account;//账户
    //取了多少钱
    int drawingMoney;
    //现在手里有多少钱
    int nowMoney;

    public Drawing(Account account,int drawingMoney,String name){
        super(name);
        this.account = account;
        this.drawingMoney = drawingMoney;

    }

    @Override
    public void run() {
        synchronized (account){
            //判断有没有钱
            if (account.money-drawingMoney<0){
                System.out.println(Thread.currentThread().getName()+"钱不够,取不了");
                return;
            }
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            account.money = account.money - drawingMoney;
            nowMoney = nowMoney + drawingMoney;

            System.out.println(account.name+"余额为"+account.money);
            //Thread.currentThread().getName()=this.getName()

            System.out.println(this.getName()+"手里的钱"+nowMoney);
        }

    }
}

 

 

synchronized与Lock的对比