Java并发Lock接口详解-优快云博客

本文链接：https://blog.youkuaiyun.com/art_code/article/details/90509599

本文深入探讨了Java并发包中的Lock接口及其相关实现类，对比synchronized关键字，讲解了Lock锁的非阻塞性、中断响应性和定时锁获取特性。通过实例代码展示了Lock和Condition在生产者消费者模式中的应用。

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关于lock锁

在 jdk1.5 之后，并发包中新增了 Lock 接口(以及相关实现类)用来实现锁功能，Lock 接口提供了与 synchronized 关键字类似的同步功能，但需要在使用时手动获取锁和释放锁。

lock锁也叫显示锁

大家看下这个lock锁:

lock是个接口

这个接口下面很多锁：

对于lock锁的使用，实现生产者消费者模式的：

package com.toov5.thread;

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

//共享对象
class ResLock {
    public boolean flag = true;
    public String sex;
    public String name;
    public Lock lock = new ReentrantLock();
}
class inputThreadLock extends Thread {
    public ResLock res;

    public inputThreadLock(ResLock res) {
        this.res = res;
    }
    @Override
    public void run() {
        int count = 0;
        while (true) {
            try {
                res.lock.lock();
                if (count == 0) {
                    res.name = "lucy";
                    res.sex = "girl";
                } else {
                    res.name = "Jack";
                    res.sex = "boy";
                }
            count = (count + 1) % 2;
            } catch (Exception e) {
            }finally{
                res.lock.unlock();  //释放锁写在finally里面
            }
        
        }
    }
}
class readThreadLock extends Thread {
    public ResLock res;

    public readThreadLock(ResLock res) {
        this.res = res;
    }
    @Override
    public void run() {
        while (true) {
            try {
                res.lock.lock();
                System.out.println(res.name + "," + res.sex);
                
            } catch (Exception e) {
                e.printStackTrace();
            }finally {
                res.lock.unlock();
            }
            
        }
    }
}
public class LockTest {
    public static void main(String[] args) {
        Res res = new Res();
        inputThread inputThread = new inputThread(res);
        readThread  readThread = new readThread(res);
        inputThread.start();
        readThread.start();
    }    
}

注意 unlock写到finally里面哦

然后lock锁里面的类似于 notify 和 wait的 Condition

Condition的功能类似于在传统的线程技术中的,Object.wait()和Object.notify()的功能。

使用方法：

package com.toov5.thread;

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

//共享对象
class ResLock {
    public boolean flag = true;
    public String sex;
    public String name;
    public Lock lock = new ReentrantLock();
    public Condition condition  = lock.newCondition();
}
class inputThreadLock extends Thread {
    public ResLock res;

    public inputThreadLock(ResLock res) {
        this.res = res;
    }
    @Override
    public void run() {
        if (res.flag) {
            try {
                res.condition.await();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        int count = 0;
        while (true) {
            
            try {
                res.lock.lock();
                if (count == 0) {
                    res.name = "lucy";
                    res.sex = "girl";
                } else {
                    res.name = "Jack";
                    res.sex = "boy";
                }
            count = (count + 1) % 2;
            res.flag=true;
            res.condition.signal();
            } catch (Exception e) {
            }finally{
                res.lock.unlock();  //释放锁写在finally里面
            }
        
        }
    }
}
class readThreadLock extends Thread {
    public ResLock res;

    public readThreadLock(ResLock res) {
        this.res = res;
    }
    @Override
    public void run() {
        while (true) {
            try {
                res.lock.lock();
                if (res.flag) {
                    res.condition.await();
                }
                System.out.println(res.name + "," + res.sex);
                res.condition.signal();
            } catch (Exception e) {
                e.printStackTrace();
            }finally {
                res.lock.unlock();
            }
            
        }
    }
}
public class LockTest {
    public static void main(String[] args) {
        Res res = new Res();
        inputThread inputThread = new inputThread(res);
        readThread  readThread = new readThread(res);
        inputThread.start();
        readThread.start();
    }    
}