标签：blog io 使用 ar java for sp div art
半路出家学习java, 花了几分钟简单看了。在早上那个例子上稍微改了下，
我的理解是在java synchronized只是个线程同步标志，但是不会堵塞线程，而wait会堵塞调用者线程，类windows的堵塞函数，而notify相当于解锁（个人把这个过程当临界区来理解的），下边例子主要是，默认先运行的线程test1会先执行， 我稍微改了下， 让第一个线程挂起，等第二个线程执行完，再执行第一个线程
代码
import java.util.concurrent.CountDownLatch;
public class CountDown {
private static CountDownLatch connectedSignal = new CountDownLatch(50);
static class MyThread implements Runnable {
public void run() {
Thread current = Thread.currentThread();
System.out.println(current.getName());
synchronized (connectedSignal) {
Thread thread = Thread.currentThread();
String name = thread.getName();
if (name.equals("test1")){
try {
connectedSignal.wait();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
for (int i = 0; i < 25; ++i) {
sale();
}
if (name.equals("test2")){
connectedSignal.notify();
}
}
}
public synchronized void sale() {
if (connectedSignal.getCount() > 0) {
Thread current = Thread.currentThread();
connectedSignal.countDown();
System.out.println("Thread id" + current.getId() + "value = "
+ connectedSignal.getCount());
}
}
}
public static void main(String[] args) throws InterruptedException {
MyThread my = new MyThread();
Thread t1 = new Thread(my, "test1");
Thread t2 = new Thread(my, "test2");
t1.start();
t2.start();
connectedSignal.await(); // 等待结束
System.out.println(connectedSignal.getCount());
}
}
又花了几分钟稍微改了下， 让两个线程轮流执行
import java.util.concurrent.CountDownLatch;
public class CountDown {
private static CountDownLatch connectedSignal = new CountDownLatch(50);
static class MyThread implements Runnable {
public void run() {
Thread current = Thread.currentThread();
System.out.println(current.getName());
synchronized (connectedSignal) {
Thread thread = Thread.currentThread();
String name = thread.getName();
// if (name.equals("test1")){
// try {
// connectedSignal.wait();
// } catch (InterruptedException e) {
// // TODO Auto-generated catch block
// e.printStackTrace();
// }
// }
for (int i = 0; i < 25; ++i) {
if (name.equals("test1") && (i % 2 == 0)){
try {
sale();
connectedSignal.notify();
connectedSignal.wait();
connectedSignal.notify();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
else{
sale();
connectedSignal.notify();
try {
connectedSignal.wait();
connectedSignal.notify();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
// if (name.equals("test2")){
// connectedSignal.notify();
// }
}
}
public synchronized void sale() {
if (connectedSignal.getCount() > 0) {
Thread current = Thread.currentThread();
connectedSignal.countDown();
System.out.println("Thread id" + current.getId() + "value = "
+ connectedSignal.getCount());
}
}
}
public static void main(String[] args) throws InterruptedException {
MyThread my = new MyThread();
Thread t1 = new Thread(my, "test1");
Thread t2 = new Thread(my, "test2");
t1.start();
t2.start();
connectedSignal.await(); // 等待结束
System.out.println(connectedSignal.getCount());
}
}
结果和我想的一样。感觉本身线程使用挺简单的，java估计是为了开发者更方便开发， 自己封装再提供了更多的功能，反倒让我很不习惯。
纯粹本人观点， 有错误欢迎指出.
标签：blog io 使用 ar java for sp div art
原文地址：http://www.cnblogs.com/chengxin1982/p/3997215.html
