浅谈多线程中的锁的几种用法总结(必看)

一、ReentrantLock

package com.ietree.basicskill.mutilthread.lock;

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

/**
* Created by Administrator on 2017/5/17.
*/
public class UseReentrantLock {

private Lock lock = new ReentrantLock();

public void method1(){
   try {
     lock.lock();
     System.out.println("当前线程:" + Thread.currentThread().getName() + "进入method1..");
     Thread.sleep(1000);
     System.out.println("当前线程:" + Thread.currentThread().getName() + "退出method1..");
     Thread.sleep(1000);
   } catch (InterruptedException e) {
     e.printStackTrace();
   } finally {

lock.unlock();
   }
 }

public void method2(){
   try {
     lock.lock();
     System.out.println("当前线程:" + Thread.currentThread().getName() + "进入method2..");
     Thread.sleep(2000);
     System.out.println("当前线程:" + Thread.currentThread().getName() + "退出method2..");
     Thread.sleep(1000);
   } catch (InterruptedException e) {
     e.printStackTrace();
   } finally {

lock.unlock();
   }
 }

public static void main(String[] args) {

final UseReentrantLock ur = new UseReentrantLock();
   Thread t1 = new Thread(new Runnable() {
     @Override
     public void run() {
       ur.method1();
       ur.method2();
     }
   }, "t1");

t1.start();
   try {
     Thread.sleep(10);
   } catch (InterruptedException e) {
     e.printStackTrace();
   }
   //System.out.println(ur.lock.getQueueLength());
 }

}

二、ReentrantReadWriteLock

package com.ietree.basicskill.mutilthread.lock;

import java.util.concurrent.locks.ReentrantReadWriteLock;

/**
* Created by Administrator on 2017/5/17.
*/
public class UseReentrantReadWriteLock {

private ReentrantReadWriteLock rwLock = new ReentrantReadWriteLock();
 private ReentrantReadWriteLock.ReadLock readLock = rwLock.readLock();
 private ReentrantReadWriteLock.WriteLock writeLock = rwLock.writeLock();

public void read(){
   try {
     readLock.lock();
     System.out.println("当前线程:" + Thread.currentThread().getName() + "进入...");
     Thread.sleep(3000);
     System.out.println("当前线程:" + Thread.currentThread().getName() + "退出...");
   } catch (Exception e) {
     e.printStackTrace();
   } finally {
     readLock.unlock();
   }
 }

public void write(){
   try {
     writeLock.lock();
     System.out.println("当前线程:" + Thread.currentThread().getName() + "进入...");
     Thread.sleep(3000);
     System.out.println("当前线程:" + Thread.currentThread().getName() + "退出...");
   } catch (Exception e) {
     e.printStackTrace();
   } finally {
     writeLock.unlock();
   }
 }

public static void main(String[] args) {

final UseReentrantReadWriteLock urrw = new UseReentrantReadWriteLock();

Thread t1 = new Thread(new Runnable() {
     @Override
     public void run() {
       urrw.read();
     }
   }, "t1");
   Thread t2 = new Thread(new Runnable() {
     @Override
     public void run() {
       urrw.read();
     }
   }, "t2");
   Thread t3 = new Thread(new Runnable() {
     @Override
     public void run() {
       urrw.write();
     }
   }, "t3");
   Thread t4 = new Thread(new Runnable() {
     @Override
     public void run() {
       urrw.write();
     }
   }, "t4");

//    t1.start();
//    t2.start();

//    t1.start(); // R
//    t3.start(); // W

t3.start();
   t4.start();
 }
}

三、Condition

package com.ietree.basicskill.mutilthread.lock;

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

/**
* Created by Administrator on 2017/5/17.
*/
public class UseCondition {
 private Lock lock = new ReentrantLock();
 private Condition condition = lock.newCondition();

public void method1(){
   try {
     lock.lock();
     System.out.println("当前线程：" + Thread.currentThread().getName() + "进入等待状态..");
     Thread.sleep(3000);
     System.out.println("当前线程：" + Thread.currentThread().getName() + "释放锁..");
     condition.await();  // Object wait
     System.out.println("当前线程：" + Thread.currentThread().getName() +"继续执行...");
   } catch (Exception e) {
     e.printStackTrace();
   } finally {
     lock.unlock();
   }
 }

public void method2(){
   try {
     lock.lock();
     System.out.println("当前线程：" + Thread.currentThread().getName() + "进入..");
     Thread.sleep(3000);
     System.out.println("当前线程：" + Thread.currentThread().getName() + "发出唤醒..");
     condition.signal();    //Object notify
   } catch (Exception e) {
     e.printStackTrace();
   } finally {
     lock.unlock();
   }
 }

public static void main(String[] args) {

final UseCondition uc = new UseCondition();
   Thread t1 = new Thread(new Runnable() {
     @Override
     public void run() {
       uc.method1();
     }
   }, "t1");
   Thread t2 = new Thread(new Runnable() {
     @Override
     public void run() {
       uc.method2();
     }
   }, "t2");
   t1.start();

t2.start();
 }
}

四、ManyCondition

package com.ietree.basicskill.mutilthread.lock;

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

/**
* Created by Administrator on 2017/5/17.
*/
public class UseManyCondition {
 private ReentrantLock lock = new ReentrantLock();
 private Condition c1 = lock.newCondition();
 private Condition c2 = lock.newCondition();

public void m1(){
   try {
     lock.lock();
     System.out.println("当前线程：" +Thread.currentThread().getName() + "进入方法m1等待..");
     c1.await();
     System.out.println("当前线程：" +Thread.currentThread().getName() + "方法m1继续..");
   } catch (Exception e) {
     e.printStackTrace();
   } finally {
     lock.unlock();
   }
 }

public void m2(){
   try {
     lock.lock();
     System.out.println("当前线程：" +Thread.currentThread().getName() + "进入方法m2等待..");
     c1.await();
     System.out.println("当前线程：" +Thread.currentThread().getName() + "方法m2继续..");
   } catch (Exception e) {
     e.printStackTrace();
   } finally {
     lock.unlock();
   }
 }

public void m3(){
   try {
     lock.lock();
     System.out.println("当前线程：" +Thread.currentThread().getName() + "进入方法m3等待..");
     c2.await();
     System.out.println("当前线程：" +Thread.currentThread().getName() + "方法m3继续..");
   } catch (Exception e) {
     e.printStackTrace();
   } finally {
     lock.unlock();
   }
 }

public void m4(){
   try {
     lock.lock();
     System.out.println("当前线程：" +Thread.currentThread().getName() + "唤醒..");
     c1.signalAll();
   } catch (Exception e) {
     e.printStackTrace();
   } finally {
     lock.unlock();
   }
 }

public void m5(){
   try {
     lock.lock();
     System.out.println("当前线程：" +Thread.currentThread().getName() + "唤醒..");
     c2.signal();
   } catch (Exception e) {
     e.printStackTrace();
   } finally {
     lock.unlock();
   }
 }

public static void main(String[] args) {

final UseManyCondition umc = new UseManyCondition();
   Thread t1 = new Thread(new Runnable() {
     @Override
     public void run() {
       umc.m1();
     }
   },"t1");
   Thread t2 = new Thread(new Runnable() {
     @Override
     public void run() {
       umc.m2();
     }
   },"t2");
   Thread t3 = new Thread(new Runnable() {
     @Override
     public void run() {
       umc.m3();
     }
   },"t3");
   Thread t4 = new Thread(new Runnable() {
     @Override
     public void run() {
       umc.m4();
     }
   },"t4");
   Thread t5 = new Thread(new Runnable() {
     @Override
     public void run() {
       umc.m5();
     }
   },"t5");

t1.start();  // c1
   t2.start();  // c1
   t3.start();  // c2

try {
     Thread.sleep(2000);
   } catch (InterruptedException e) {
     e.printStackTrace();
   }

t4.start();  // c1
   try {
     Thread.sleep(2000);
   } catch (InterruptedException e) {
     e.printStackTrace();
   }
   t5.start();  // c2

}
}