java多线程安全加锁

1，同步锁
2，lock锁(更加灵活)
3，锁对象的等待和唤醒

1，同步锁

public class IMTicketSeller implements Runnable {

    private int ticketCount = 1000;
    private Object obj = new Object();

    @Override
    public void run() {

        while (true){
            /*synchronized (obj) {
                if (ticketCount > 0){
                    try {
                        Thread.sleep(10);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    System.out.println(Thread.currentThread().getName() + "    " + ticketCount--);
                }
            }*/
            sellTicket();
        }
    }

    //这里同步用synchronized，不用创建对象作为参数传给同步锁
    public  synchronized  void sellTicket(){
        if (ticketCount > 0){
            System.out.println(Thread.currentThread().getName() + "    " + ticketCount--);
        }
    }
}

//测试：
public class Test {

    public static void main(String[] args) {

        //开两个窗口进行票务售卖
        ExecutorService exeService = Executors.newFixedThreadPool(3);

        IMTicketSeller seller = new IMTicketSeller();
        exeService.submit(seller);
        exeService.submit(seller);

        exeService.shutdown();
    }
}

2，lock锁(更加灵活)，也就是把1中的同步锁换成lock锁

/*
 * 使用系统自带的lock，取代掉同步代码块
 */

import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

public class IMTicketSeller01 implements Runnable {
    private int ticketCount = 1000;
    private Lock lock = new ReentrantLock();
    @Override
    public void run() {
        while (true){
            sellTicket();
        }
    }
    //这里同步用synchronized，不用创建对象作为参数传给同步锁
    public void sellTicket(){
        lock.lock();
        if (ticketCount > 0){
            System.out.println(Thread.currentThread().getName() + "    " + ticketCount--);
        }
        lock.unlock();
    }
}

//测试：
public class Test01 {

    public static void main(String[] args) {

        //开两个窗口进行票务售卖
        AtomicReference exeService = new AtomicReference<>(Executors.newFixedThreadPool(3));

        IMTicketSeller01 seller = new IMTicketSeller01();
        exeService.get().submit(seller);
        exeService.get().submit(seller);

        exeService.get().shutdown();
    }
}

3，锁对象的等待和唤醒

*情景是：一个Person类，一个输入对象负责给Person赋值，一个输出对象负责打印Person，输出对象需要等待输入对象完成之后才能进行输出。这里输入对象是做的一个循环，奇数和偶数输入两个不同的内容 *

//Person类
public class public class Person {

    String name;
    String sex;
    boolean isAssigned = false;

    //把构造方法私有化
    Person(){
        super();
    }

    @Override
    public String toString() {
        return "Person{" +
                "name='" + name + '\'' +
                ", sex='" + sex + '\'' +
                '}';
    }
} {
    String name;
    String sex;
    boolean isAssigned = false;
    //把构造方法私有化
    Person(){
        super();
    }
    @Override
    public String toString() {
        return "Person{" +
                "name='" + name + '\'' +
                ", sex='" + sex + '\'' +
                '}';
    }
}

//Input输入对象类
public class public class Input implements  Runnable{
    private Person p;
    public Input(Person p) {
        this.p = p;
    }
    @Override
    public void run() {
        System.out.println("00000");
        int i = 0;
        while (true) {
            synchronized (p){
                //锁对象的唤醒和等待必须要在同步锁内部
                if (p.isAssigned == true) {
                    try {
                        p.wait();
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
                if (i % 2 == 0) {
                    p.name = "zhangdanfeng";
                    p.sex = "man";
                }else{
                    p.name = "0000000";
                    p.sex = "11111111`";
                }
                i++;
                p.isAssigned = true;
                p.notify();
            }
        }
    }
} implements  Runnable{
    private Person p;
    public Input(Person p) {
        this.p = p;
    }
    @Override
    public void run() {
        System.out.println("00000");
        int i = 0;
        while (true) {
            synchronized (p){
                //锁对象的唤醒和等待必须要在同步锁内部
                if (p.isAssigned == true) {
                    try {
                        p.wait();
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
                if (i % 2 == 0) {
                    p.name = "zhangdanfeng";
                    p.sex = "man";
                }else{
                    p.name = "0000000";
                    p.sex = "11111111`";
                }
                i++;
                p.isAssigned = true;
                p.notify();
            }
        }
    }
}


//Output输出类
public class Output implements Runnable {
    private  Person p;
    public Output(Person p) {
        this.p = p;
    }
    @Override
    public void run() {
        System.out.println("11111");
        while (true) {
            synchronized (p) {
                //锁对象的唤醒和等待必须要在同步锁内部
                if (p.isAssigned == false) {
                    try {
                        p.wait();
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
                System.out.println(p);
                p.isAssigned = false;
                p.notify();
            }
        }
    }
}


//测试
public class Test {
    public static void main(String[] args) {
        Person person = new Person();
        Input input = new Input(person);
        Output output = new Output(person);

        new Thread(input).start();
        new Thread(output).start();
    }
}