有2中方法可以来创建线程：
- 继承Thread类
- 用一个类实现Runnable接口
具体如下:
package com.qingke.thread;
public class LeannThread {
public static void main(String[] args) {
Thread code = new Code();
code.setName("编写");
Print print = new Print();
Thread pr = new Thread(print, "打印机");
code.start();
pr.start();
}
}
class Code extends Thread {
public void run() {
for (int i = 1; i <= 100; i++) {
System.out.println(this.getName() + ":" + "小明在写第" + i + "行代码");
try {
Thread.sleep(10);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
System.out.println("代码写完！");
}
}
class Print implements Runnable {
@Override
public void run() {
for (int i = 1; i <= 15; i++) {
System.out.println(Thread.currentThread().getName() + ":" + "小明在打印第" + i + "页材料");
try {
Thread.sleep(10);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
System.out.println("打印完！");
}
}
在对于像银行账户的需要同步的问题上，现在有一个例子：
一对夫妻在银行有一个共同的账户，则需要用到同步使得账户中的余额保持同步。
如下：
package com.qingke.thread;
public class BankThread {
public static void main(String[] args) {
BankAccount count = new BankAccount();
Thread husband = new BankedThread(count);
Thread wife = new BankedThread(count);
husband.start();
wife.start();
}
}
class BankAccount {
private double balance = 1000;
public /*synchronized*/boolean deposit(double newAdd) {
if (balance <= 0) {
return false;
} else {
synchronized (this) {
System.out.println("当前余额为" + balance);
balance += newAdd;
System.out.println("当前余额为" + balance);
}
return true;
}
}
}
class BankedThread extends Thread {
private BankAccount bankAccount;
public BankedThread(BankAccount count) {
bankAccount = count;
}
public void run() {
bankAccount.deposit(200);
}
}
在上述代码中synchronized 可以直接放在方法声明上，也可以写在方法块内synchronized（obj）{} * ** obj*表示需要同步的对象。
模拟一种场景，假设有一个生产商Producer和一个消费者Consumer，另外有一个容器Box，Box中只能放一样东西。若Box为空，则要等Producer生产出来再放到Box中，在通知Consumer。若Box中不空，则需要等Consumer拿完，在通知Producer。
代码如下：
package com.qingke.thread;
public class LearnThreadCommunication {
public static void main(String[] args) {
Box box = new Box();
Thread producer = new Producer(box);
Thread consumer = new Consumer(box);
producer.start();
consumer.start();
}
}
class Box {
public int boxValue = 0;
}
class Producer extends Thread {
private Box box;
public Producer(Box box) {
this.box = box;
}
public void run() {
for (int i = 1; i < 6; i++) {
synchronized (box) {
while (box.boxValue != 0) {
try {
System.out.println("Producer: Box是满的，等待");
box.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
box.boxValue = i;
System.out.println("Producer: Box中放入了" + i + ",并通知其他等待者");
box.notify();
}
}
}
}
class Consumer extends Thread {
private Box box;
public Consumer(Box box) {
this.box = box;
}
public void run() {
for (int i = 1; i < 6; i++) {
synchronized (box) {
while (box.boxValue == 0) {
try {
System.out.println("Consumer: Box是空的，等待");
box.wait();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
box.boxValue = 0;
System.out.println("Consumer: Box中取出了" + i + ",并通知供应者");
box.notify();
}
}
}
}
用到Object的 wait()和notify()方法
