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浅谈多线程中的锁的几种用法总结(必看)

程序员文章站 2024-02-16 16:01:04
一、reentrantlock package com.ietree.basicskill.mutilthread.lock; import java.ut...

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

  }
}

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