java 中Lock的使用
ReentrantLock也可以讓代碼塊原子執行，可是比synchronized更增強大，ReentrantLock具備嗅探鎖定、多路分支通知等功能。
嗅探鎖定：是指獲取鎖時若是鎖已經被其餘線程獲取到ReentrantLock能夠進行指定等待時間獲取鎖或者
多路分支通知：是指線程發生await時，線程能夠選擇註冊在不一樣的監視器Condition對象上，在適當的時候能夠選擇指定的監視器Condition對象上的線程進行signal通知、執行java
一、多線程執行同一代碼塊互斥
import java.util.concurrent.locks.ReentrantLock;
class MyService {
private ReentrantLock lock = new ReentrantLock();
public void method() {
try {
lock.lock();
for (int i = 1; i <= 3; i++) {
Thread.sleep(1000);
System.out.println("ThreadName=" + Thread.currentThread().getName() + " " + i);
}
} catch (InterruptedException e) {
e.printStackTrace();
}finally {
lock.unlock();
}
}
}
class MyThread extends Thread {
private MyService service;
MyThread(MyService service) {
this.service = service;
}
@Override
public void run() {
service.method();
}
}
public class Test {
public static void main(String[] args) {
MyService service = new MyService();
MyThread myThread1 = new MyThread(service);
MyThread myThread2 = new MyThread(service);
myThread1.start();
myThread2.start();
}
}
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結果
ThreadName=Thread-0 1
ThreadName=Thread-0 2
ThreadName=Thread-0 3
ThreadName=Thread-1 1
ThreadName=Thread-1 2
ThreadName=Thread-1 3多線程
二、多線程執行不一樣代碼塊互斥
import java.util.concurrent.locks.ReentrantLock;
class MyService {
private ReentrantLock lock = new ReentrantLock();
public void methodA() {
lock.lock();
try {
System.out.println("MethodA begin ThreadName=" + Thread.currentThread().getName());
for (int i = 1; i <= 3; i++) {
System.out.println("ThreadName=" + Thread.currentThread().getName() + " " + i);
Thread.sleep(1000);
}
System.out.println("MethodA end ThreadName=" + Thread.currentThread().getName());
} catch (InterruptedException e) {
e.printStackTrace();
} finally {
lock.unlock();
}
}
public void methodB() {
lock.lock();
try {
System.out.println("MethodB begin ThreadName=" + Thread.currentThread().getName());
for (int i = 1; i <= 3; i++) {
System.out.println("ThreadName=" + Thread.currentThread().getName() + " " + i);
Thread.sleep(1000);
}
System.out.println("MethodB end ThreadName=" + Thread.currentThread().getName());
} catch (InterruptedException e) {
e.printStackTrace();
} finally {
lock.unlock();
}
}
}
class ThreadA extends Thread {
private MyService service;
ThreadA(MyService service) {
this.service = service;
}
@Override
public void run() {
service.methodA();
}
}
class ThreadB extends Thread {
private MyService service;
ThreadB(MyService service) {
this.service = service;
}
@Override
public void run() {
service.methodB();
}
}
public class Test {
public static void main(String[] args) {
MyService service = new MyService();
ThreadA threadA = new ThreadA(service);
threadA.setName("A");
ThreadB threadB = new ThreadB(service);
threadB.setName("B");
threadA.start();
threadB.start();
}
}
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結果：
MethodA begin ThreadName=A
ThreadName=A 1
ThreadName=A 2
ThreadName=A 3
MethodA end ThreadName=A
MethodB begin ThreadName=B
ThreadName=B 1
ThreadName=B 2
ThreadName=B 3
MethodB end ThreadName=Bide
三、多路通知
當多線程進入await狀態時，利用Condition監視器對不一樣類型線程通知測試
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.ReentrantLock;
class MyService {
private ReentrantLock lock = new ReentrantLock();
private Condition conditionA = lock.newCondition();
private Condition conditionB = lock.newCondition();
public void methodA() {
lock.lock();
try {
System.out.println("MethodA begin ThreadName=" + Thread.currentThread().getName() + " " + System.currentTimeMillis());
conditionA.await();
System.out.println("MethodA end ThreadName=" + Thread.currentThread().getName() + " " + System.currentTimeMillis());
} catch (InterruptedException e) {
e.printStackTrace();
} finally {
lock.unlock();
}
}
public void methodB() {
lock.lock();
try {
System.out.println("MethodB begin ThreadName=" + Thread.currentThread().getName() + " " + System.currentTimeMillis());
conditionB.await();
System.out.println("MethodB end ThreadName=" + Thread.currentThread().getName() + " " + System.currentTimeMillis());
} catch (InterruptedException e) {
e.printStackTrace();
} finally {
lock.unlock();
}
}
public void signalA() {
lock.lock();
conditionA.signal();
lock.unlock();
}
public void signalA_All() {
lock.lock();
conditionA.signalAll();
lock.unlock();
}
public void signalB() {
lock.lock();
conditionB.signal();
lock.unlock();
}
public void signalB_All() {
lock.lock();
conditionB.signalAll();
lock.unlock();
}
}
class ThreadA extends Thread {
private MyService service;
ThreadA(MyService service) {
this.service = service;
}
@Override
public void run() {
service.methodA();
}
}
class ThreadB extends Thread {
private MyService service;
ThreadB(MyService service) {
this.service = service;
}
@Override
public void run() {
service.methodB();
}
}
public class Test {
public static void main(String[] args) throws InterruptedException {
MyService service = new MyService();
ThreadA threadA = new ThreadA(service);
threadA.setName("A");
ThreadB threadB = new ThreadB(service);
threadB.setName("B");
threadA.start();
threadB.start();
Thread.sleep(1000);
service.signalA();
Thread.sleep(1000);
service.signalB();
// ThreadA[] threadAs = new ThreadA[10];
// for (int i=0;i<5;i++){
// threadAs[i] = new ThreadA(service);
// }
// ThreadB[] threadBs = new ThreadB[10];
// for (int i=0;i<5;i++){
// threadBs[i] = new ThreadB(service);
// }
//
// for (int i=0;i<5;i++){
// threadAs[i].start();
// threadBs[i].start();
// }
//
// Thread.sleep(1000);
// service.signalA_All();
// Thread.sleep(1000);
// service.signalB_All();
}
}
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測試結果1：
MethodA begin ThreadName=A 1476800025028
MethodB begin ThreadName=B 1476800025029
MethodA end ThreadName=A 1476800026028
MethodB end ThreadName=B 1476800027028this
修改代碼爲：spa
public static void main(String[] args) throws InterruptedException {
MyService service = new MyService();
// ThreadA threadA = new ThreadA(service);
// threadA.setName("A");
//
// ThreadB threadB = new ThreadB(service);
// threadB.setName("B");
// threadA.start();
// threadB.start();
//
// Thread.sleep(1000);
// service.signalA();
// Thread.sleep(1000);
// service.signalB();
ThreadA[] threadAs = new ThreadA[10];
for (int i=0;i<5;i++){
threadAs[i] = new ThreadA(service);
}
ThreadB[] threadBs = new ThreadB[10];
for (int i=0;i<5;i++){
threadBs[i] = new ThreadB(service);
}
for (int i=0;i<5;i++){
threadAs[i].start();
threadBs[i].start();
}
Thread.sleep(1000);
service.signalA_All();
Thread.sleep(1000);
service.signalB_All();
}
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結果爲：
MethodA begin ThreadName=Thread-0 1476800227416
MethodB begin ThreadName=Thread-7 1476800227417
MethodB begin ThreadName=Thread-5 1476800227417
MethodA begin ThreadName=Thread-3 1476800227418
MethodA begin ThreadName=Thread-1 1476800227418
MethodA begin ThreadName=Thread-4 1476800227418
MethodB begin ThreadName=Thread-6 1476800227418
MethodA begin ThreadName=Thread-2 1476800227418
MethodB begin ThreadName=Thread-8 1476800227418
MethodB begin ThreadName=Thread-9 1476800227418
MethodA end ThreadName=Thread-0 1476800228419
MethodA end ThreadName=Thread-3 1476800228419
MethodA end ThreadName=Thread-1 1476800228419
MethodA end ThreadName=Thread-4 1476800228420
MethodA end ThreadName=Thread-2 1476800228420
MethodB end ThreadName=Thread-7 1476800229419
MethodB end ThreadName=Thread-5 1476800229419
MethodB end ThreadName=Thread-6 1476800229419
MethodB end ThreadName=Thread-8 1476800229419
MethodB end ThreadName=Thread-9 1476800229419.net
四、公平所與非公平鎖
公平鎖是指線程獲（getting）取鎖的順序和線程鎖定（got）的順序相同，線程
Lock的一些方法說明
A） getHoldCount()
獲取當前鎖定（got）的個數
B）getQueueLength()
獲取當前正在等待獲取（getting）鎖的線程數（Threads）
C）getWaitQueueLength(Condition)
返回等待（await）與此鎖定（got）的Condition相關的個數code
版權聲明：本文爲博主原創文章，未經博主容許不得轉載。 http://blog.csdn.net/jihaitaowangyi/article/details/52852693對象
- 1. java中Lock類的使用
- 2. Java Lock的使用
- 3. Lock的使用
- 4. java 中的lock鎖
- 5. Java同步Lock,Condition使用
- 6. Lock鎖的使用
- 7. Java多線程之Lock的使用（一）
- 8. Java中的Lock與synchronized
- 9. Java中的鎖 Lock和synchronized
- 10. Java中的鎖——Lock和synchronized
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