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kimmkingkimmking
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update 0302
1 parent a19fa69 commit 5762222

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11 files changed

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11 files changed

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‎03concurrency/0301/src/main/java/java0/conc0302/lock/Count.java‎

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package java0.conc0302.lock;
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import java.util.concurrent.locks.ReentrantLock;
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public class Count {
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final ReentrantLock lock = new ReentrantLock();
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public void get() {
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// final ReentrantLock lock = new ReentrantLock();
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try {
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lock.lock();
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System.out.println(Thread.currentThread().getName() + " get begin");
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Thread.sleep(1000);
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System.out.println(Thread.currentThread().getName() + " get end");
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lock.unlock();
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} catch (InterruptedException e) {
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e.printStackTrace();
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}
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}
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public void put() {
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// final ReentrantLock lock = new ReentrantLock();
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try {
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lock.lock();
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System.out.println(Thread.currentThread().getName() + " put begin");
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Thread.sleep(1000);
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System.out.println(Thread.currentThread().getName() + " put end");
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lock.unlock();
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} catch (InterruptedException e) {
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e.printStackTrace();
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}
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}
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}

‎03concurrency/0301/src/main/java/java0/conc0302/lock/Count2.java‎

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package java0.conc0302.lock;
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import java.util.concurrent.locks.ReentrantReadWriteLock;
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public class Count2 {
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private final ReentrantReadWriteLock rwLock = new ReentrantReadWriteLock();
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public void get() {
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rwLock.readLock().lock();
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try {
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System.out.println(Thread.currentThread().getName() + " get begin");
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Thread.sleep(1000);
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System.out.println(Thread.currentThread().getName() + " get end");
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} catch (InterruptedException e) {
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e.printStackTrace();
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} finally {
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rwLock.readLock().unlock();
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}
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}
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public void put() {
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rwLock.writeLock().lock();
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try {
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System.out.println(Thread.currentThread().getName() + " put begin");
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Thread.sleep(1000);
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System.out.println(Thread.currentThread().getName() + " put end");
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} catch (InterruptedException e) {
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e.printStackTrace();
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} finally {
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rwLock.writeLock().unlock();
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}
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}
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}

‎03concurrency/0301/src/main/java/java0/conc0302/lock/Count3.java‎

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package java0.conc0302.lock;
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public class Count3 {
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private byte[] lock1 = new byte[1];
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private byte[] lock2 = new byte[1];
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public int num = 0;
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public void add() {
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synchronized (lock1) {
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try {
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Thread.sleep(1000);
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} catch (InterruptedException e) {
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e.printStackTrace();
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}
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synchronized (lock2) {
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num += 1;
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}
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System.out.println(Thread.currentThread().getName() + "_" + num);
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}
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}
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public void lockMethod() {
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synchronized (lock2) {
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try {
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Thread.sleep(1000);
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} catch (InterruptedException e) {
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e.printStackTrace();
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}
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synchronized (lock1) {
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num += 1;
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}
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System.out.println(Thread.currentThread().getName() + "_" + num);
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}
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}
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}

‎03concurrency/0301/src/main/java/java0/conc0302/lock/LockMain.java‎

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package java0.conc0302.lock;
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public class LockMain {
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public static void main(String[] args) {
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Count3 count3 = new Count3();
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ThreadA threadA = new ThreadA(count3);
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threadA.setName("线程A");
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threadA.start();
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ThreadB threadB = new ThreadB(count3);
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threadB.setName("线程B");
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threadB.start();
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}
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}

‎03concurrency/0301/src/main/java/java0/conc0302/lock/ObjectCache.java‎

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package java0.conc0302.lock;
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import java.util.concurrent.Semaphore;
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import java.util.concurrent.locks.Lock;
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import java.util.concurrent.locks.ReentrantLock;
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public class ObjectCache<T> {
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public interface ObjectFactory<T> {
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T makeObject();
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}
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class Node {
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T obj;
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Node next;
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}
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final int capacity;
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final ObjectFactory<T> factory;
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final Lock lock = new ReentrantLock();
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final Semaphore semaphore;
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private Node head;
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private Node tail;
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public ObjectCache(int capacity, ObjectFactory<T> factory) {
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this.capacity = capacity;
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this.factory = factory;
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this.semaphore = new Semaphore(this.capacity);
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this.head = null;
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this.tail = null;
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}
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public T getObject() throws InterruptedException {
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semaphore.acquire();
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return getNextObject();
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}
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private T getNextObject() {
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lock.lock();
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try {
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if (head == null) {
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return factory.makeObject();
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} else {
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Node ret = head;
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head = head.next;
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if (head == null) tail = null;
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ret.next = null;//help GC
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return ret.obj;
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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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private void returnObjectToPool(T t) {
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lock.lock();
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try {
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Node node = new Node();
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node.obj = t;
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if (tail == null) {
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head = tail = node;
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} else {
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tail.next = node;
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tail = node;
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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 returnObject(T t) {
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returnObjectToPool(t);
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semaphore.release();
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}
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}

‎03concurrency/0301/src/main/java/java0/conc0302/lock/ReentrantLockDemo.java‎

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package java0.conc0302.lock;
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public class ReentrantLockDemo {
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public static void main(String[] args) {
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final Count count = new Count();
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for (int i = 0; i < 2; i++) {
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new Thread() {
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public void run() {
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count.get();
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}
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}.start();
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}
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for (int i = 0; i < 2; i++) {
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new Thread() {
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public void run() {
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count.put();
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}
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}.start();
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}
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}
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}

‎03concurrency/0301/src/main/java/java0/conc0302/lock/ReentrantReadWriteLockDemo.java‎

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package java0.conc0302.lock;
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public class ReentrantReadWriteLockDemo {
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public static void main(String[] args) {
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final Count2 count = new Count2();
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for (int i = 0; i < 5; i++) {
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new Thread() {
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public void run() {
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count.get();
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}
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}.start();
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}
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for (int i = 0; i < 5; i++) {
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new Thread() {
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public void run() {
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count.put();
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}
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}.start();
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}
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}
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/**
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*
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* Thread-0 get begin
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Thread-1 get begin
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Thread-2 get begin
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Thread-3 get begin
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Thread-4 get begin
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Thread-0 get end
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Thread-1 get end
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Thread-2 get end
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Thread-4 get end
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Thread-3 get end
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Thread-5 put begin
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Thread-5 put end
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Thread-6 put begin
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Thread-6 put end
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Thread-7 put begin
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Thread-7 put end
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Thread-8 put begin
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Thread-8 put end
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Thread-9 put begin
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Thread-9 put end
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*
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*/
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// 读锁不互斥、写锁互斥
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}

‎03concurrency/0301/src/main/java/java0/conc0302/lock/ReentrantReadWriteLockDemo2.java‎

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package java0.conc0302.lock;
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import java.util.HashMap;
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import java.util.Map;
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import java.util.concurrent.locks.ReentrantReadWriteLock;
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public class ReentrantReadWriteLockDemo2 {
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private final Map<String, Object> map = new HashMap<>();
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private final ReentrantReadWriteLock rwLock = new ReentrantReadWriteLock();
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public Object readWrite(String key) {
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Object value = null;
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System.out.println("1.首先开启读锁去缓存中取数据");
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rwLock.readLock().lock();
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try {
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value = map.get(key);
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if (value == null) {
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System.out.println("2.数据不存在，则释放读锁，开启写锁");
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rwLock.readLock().unlock();
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rwLock.writeLock().lock();
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try {
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if (value == null) {
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value = "aaaa";
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}
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} finally {
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System.out.println("3.释放写锁");
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rwLock.writeLock().unlock();
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}
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System.out.println("4.开启读锁");
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rwLock.readLock().lock();
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}
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} finally {
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System.out.println("5.释放读锁");
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rwLock.readLock().unlock();
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}
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return value;
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}
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public static void main(String[] args) {
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ReentrantReadWriteLockDemo2 demo2 = new ReentrantReadWriteLockDemo2();
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demo2.readWrite("wangwei");
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}
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}

‎03concurrency/0301/src/main/java/java0/conc0302/lock/ThreadA.java‎

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package java0.conc0302.lock;
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public class ThreadA extends Thread {
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private Count3 count3;
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public ThreadA(Count3 count3) {
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this.count3 = count3;
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}
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public void run() {
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count3.add();
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}
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}

‎03concurrency/0301/src/main/java/java0/conc0302/lock/ThreadB.java‎

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package java0.conc0302.lock;
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public class ThreadB extends Thread {
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private Count3 count3;
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public ThreadB(Count3 count3) {
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this.count3 = count3;
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}
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public void run() {
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count3.lockMethod();
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}
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}

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