//重入鎖
private Lock lock = new ReentrantLock(); 或者private
ReentrantLock lock = new ReentrantLock();
當使用Lock來保證線程同步時，需使用Condition對象來使線程保持協調。Condition實例被綁定在一個Lock的對象上，使用Lock對象的方法newCondition()獲取Condition的實例。Condition提供了下面三種方法，來協調不同線程的同步：
1、await()：導致當前線程等待，直到其他線程調用該Condition的signal()或signalAll()方法喚醒該線程。
2、signal()：喚醒在此Lock對象上等待的單個線程。
3、signalAll()：喚醒在此Lock對象上等待的所有線程。
-------------------------------------------------------------------1-----------------------------------------------------------------
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
// 重入鎖(ReentrantLock)、重入讀寫鎖（ReentrantReadWriteLock）、線程通信(Condition)
public class Test {
private Lock lock = new ReentrantLock();
public void method1(){
try {
lock.lock();
System.out.println("當前線程:" + Thread.currentThread().getName() + "進入method1..");
Thread.sleep(1000);
System.out.println("當前線程:" + 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("當前線程:" + Thread.currentThread().getName() + "進入method2..");
Thread.sleep(2000);
System.out.println("當前線程:" + Thread.currentThread().getName() + "退出method2..");
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
} finally {
lock.unlock();
}
}
public static void main(String[] args) {
final Test ur = new Test();
Thread t1 = new Thread(new Runnable() {
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());
}
}
-------------------------------------------------------------------2-----------------------------------------------------------------
ReentrantLock+Condition實現同步【 等待喚醒】
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
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("當前線程：" +Thread.currentThread().getName() + "進入方法m1等待..");
c1.await();
System.out.println("當前線程：" +Thread.currentThread().getName() + "方法m1繼續..");
} catch (Exception e) {
e.printStackTrace();
} finally {
lock.unlock();
}
}
public void m2(){
try {
lock.lock();
System.out.println("當前線程：" +Thread.currentThread().getName() + "進入方法m2等待..");
c1.await();
System.out.println("當前線程：" +Thread.currentThread().getName() + "方法m2繼續..");
} catch (Exception e) {
e.printStackTrace();
} finally {
lock.unlock();
}
}
public void m3(){
try {
lock.lock();
System.out.println("當前線程：" +Thread.currentThread().getName() + "進入方法m3等待..");
c2.await();
System.out.println("當前線程：" +Thread.currentThread().getName() + "方法m3繼續..");
} catch (Exception e) {
e.printStackTrace();
} finally {
lock.unlock();
}
}
public void m4(){
try {
lock.lock();
System.out.println("當前線程：" +Thread.currentThread().getName() + "喚醒..");
c1.signalAll();
} catch (Exception e) {
e.printStackTrace();
} finally {
lock.unlock();
}
}
public void m5(){
try {
lock.lock();
System.out.println("當前線程：" +Thread.currentThread().getName() + "喚醒..");
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
}
}
-------------------------------------------------------------------3-----------------------------------------------------------------
public class UseCondition {
private Lock lock = new ReentrantLock();
private Condition condition = lock.newCondition();
public void method1(){
try {
lock.lock();
System.out.println("當前線程：" + Thread.currentThread().getName() + "進入等待狀態..");
Thread.sleep(3000);
System.out.println("當前線程：" + Thread.currentThread().getName() + "釋放鎖..");
condition.await();
// Object wait
System.out.println("當前線程：" + Thread.currentThread().getName() +"繼續執行...");
} catch (Exception e) {
e.printStackTrace();
} finally {
lock.unlock();
}
}
public void method2(){
try {
lock.lock();
System.out.println("當前線程：" + Thread.currentThread().getName() + "進入..");
Thread.sleep(3000);
System.out.println("當前線程：" + Thread.currentThread().getName() + "發出喚醒..");
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();
}
}
-------------------------------------------------------------------4---------------------------------------------------
重入讀寫鎖（ReentrantReadWriteLock）
import
java.util.concurrent.locks.ReentrantReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock.ReadLock;
import java.util.concurrent.locks.ReentrantReadWriteLock.WriteLock;
public class UseReentrantReadWriteLock {
private ReentrantReadWriteLock rwLock = new ReentrantReadWriteLock();
private ReadLock readLock = rwLock.readLock();
private WriteLock writeLock = rwLock.writeLock();
public void read(){
try {
readLock.lock();
System.out.println("當前線程:" + Thread.currentThread().getName() + "進入...");
Thread.sleep(3000);
System.out.println("當前線程:" + Thread.currentThread().getName() + "退出...");
} catch (Exception e) {
e.printStackTrace();
} finally {
readLock.unlock();
}
}
public void write(){
try {
writeLock.lock();
System.out.println("當前線程:" + Thread.currentThread().getName() + "進入...");
Thread.sleep(3000);
System.out.println("當前線程:" + 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();
}
}