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lihengminglihengming
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add > juc lock test code
1 parent fd2bece commit d953aa0

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‎concurrent/src/main/java/juc/lock/ConditionTest.java‎

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package juc.lock;
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import java.util.concurrent.locks.Condition;
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import java.util.concurrent.locks.Lock;
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import java.util.concurrent.locks.ReentrantLock;
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/**
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* Created by 李恒名 on 2017/6/18.
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*/
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public class ConditionTest {
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private final Lock lock = new ReentrantLock();
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private final Condition condition = lock.newCondition();
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public void work() {
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lock.lock();
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try {
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try {
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System.out.println("Begin Work");
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condition.await();
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System.out.println("Begin End");
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} catch (InterruptedException e) {
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e.printStackTrace();
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}
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} finally {
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lock.unlock();
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}
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}
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public void continueWork() {
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lock.lock();
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try {
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condition.signalAll();
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} finally {
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lock.unlock();
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}
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}
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public static void main(String[] args) throws InterruptedException {
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ConditionTest test = new ConditionTest();
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new Thread(() -> test.work()).start();
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//等待3000毫秒后唤醒，继续工作。
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Thread.sleep(3000);
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test.continueWork();
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}
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}

‎concurrent/src/main/java/juc/lock/ReentrantLockTest.java‎

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package juc.lock;
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import java.util.concurrent.locks.Lock;
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import java.util.concurrent.locks.ReentrantLock;
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/**
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* Created by 李恒名 on 2017/6/17.
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*/
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public class ReentrantLockTest {
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private final Lock lock = new ReentrantLock();
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private String content = "Old";
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public void write() {
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lock.lock();
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//由于ReentrantLock是可重入锁，所以可以重复的加锁。
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//lock.lock();
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//lock.lock();
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System.out.println(Thread.currentThread() +" LOCK");
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try {
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try {
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//模拟方法需要执行100毫秒
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Thread.sleep(100);
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} catch (InterruptedException e) {
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e.printStackTrace();
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}
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content = "New";
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System.out.println(Thread.currentThread() +" Write content to: " + content);
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} finally {
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System.out.println(Thread.currentThread() +" UNLOCK");
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lock.unlock();
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//进行多少次加锁操作，也需要对应多少次解锁操作。
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//lock.unlock();
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//lock.unlock();
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}
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}
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public void read() {
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lock.lock();
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System.out.println(Thread.currentThread() +" LOCK");
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try {
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try {
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//模拟方法需要执行100毫秒
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Thread.sleep(100);
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} catch (InterruptedException e) {
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e.printStackTrace();
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}
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System.out.println(Thread.currentThread() +" Read content is: " + content);
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} finally {
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System.out.println(Thread.currentThread() +" UNLOCK");
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lock.unlock();
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}
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}
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public static void main(String[] args) {
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final ReentrantLockTest test = new ReentrantLockTest();
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// 使用Java 8 lambda 简化代码
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new Thread(() -> test.write()).start();
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new Thread(() -> test.read()).start();
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new Thread(() -> test.read()).start();
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/**
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不使用锁的输出：
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Thread[Thread-1,5,main] Read content is: Old
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Thread[Thread-2,5,main] Read content is: Old
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Thread[Thread-0,5,main] Write content to: New
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使用锁后：
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Thread[Thread-0,5,main] LOCK
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Thread[Thread-0,5,main] Write content to: New
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Thread[Thread-0,5,main] UNLOCK
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Thread[Thread-1,5,main] LOCK
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Thread[Thread-1,5,main] Read content is: New
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Thread[Thread-1,5,main] UNLOCK
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Thread[Thread-2,5,main] LOCK
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Thread[Thread-2,5,main] Read content is: New
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Thread[Thread-2,5,main] UNLOCK
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**/
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}
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}

‎concurrent/src/main/java/juc/lock/ReentrantReadWriteLockTest.java‎

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package juc.lock;
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import java.util.concurrent.locks.ReadWriteLock;
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import java.util.concurrent.locks.ReentrantReadWriteLock;
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/**
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* Created by 李恒名 on 2017/6/17.
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*/
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public class ReentrantReadWriteLockTest {
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private final ReadWriteLock lock = new ReentrantReadWriteLock();
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private String content = "Old";
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public void write() {
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lock.writeLock().lock();
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System.out.println(Thread.currentThread() +" LOCK");
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try {
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try {
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//模拟方法需要执行100毫秒
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Thread.sleep(100);
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} catch (InterruptedException e) {
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e.printStackTrace();
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}
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content = "New";
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System.out.println(Thread.currentThread() +" Write content to: " + content);
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} finally {
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System.out.println(Thread.currentThread() +" UNLOCK");
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lock.writeLock().unlock();
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}
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}
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public void read() {
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lock.readLock().lock();
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System.out.println(Thread.currentThread() +" LOCK");
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try {
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try {
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//模拟方法需要执行100毫秒
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Thread.sleep(100);
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} catch (InterruptedException e) {
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e.printStackTrace();
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}
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System.out.println(Thread.currentThread() +" Read content is: " + content);
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} finally {
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System.out.println(Thread.currentThread() +" UNLOCK");
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lock.readLock().unlock();
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}
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}
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public static void main(String[] args) {
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final ReentrantReadWriteLockTest test = new ReentrantReadWriteLockTest();
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// 使用Java 8 lambda 简化代码
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new Thread(() -> test.write()).start();
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new Thread(() -> test.read()).start();
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new Thread(() -> test.read()).start();
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/**
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输出：
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Thread[Thread-0,5,main] LOCK
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Thread[Thread-0,5,main] Write content to: New
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Thread[Thread-0,5,main] UNLOCK
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Thread[Thread-1,5,main] LOCK
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Thread[Thread-2,5,main] LOCK
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Thread[Thread-1,5,main] Read content is: New
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Thread[Thread-2,5,main] Read content is: New
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Thread[Thread-1,5,main] UNLOCK
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Thread[Thread-2,5,main] UNLOCK
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可以看到两个线程在读的时候可以同时获得锁
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**/
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}
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}

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