java线程池拓展 固定、可变、

线程池的介绍
1 常用的 池化技术
C3P0
DBCP
2 线程池的衍生
频繁的创建线程对象和多线程之间进行上下文切换,是非常耗时间和资源的所以JDK1.5中提出了线程池技术
3 使用线程池
Exector
4 线程池的创建
1 创建一个固定大小的线程池 ( 最常用的方法 )

ExecutorService pool = Executors.newFixedThreadPool(2);
Runnable task = new Runnable() {
@Override
public void run() {
while (true) {
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println(Thread.currentThread().getName());
}
}
};
pool.execute(task);
pool.execute(task);
pool.execute(task);//线程池的带下只有两个 现在这个任务在其等待队列中排队等候

	2  创建可变大小的线程池

     
     
     
     

      
      
      
      
1
     
     
     
     

ExecutorService pool = Executors.newCachedThreadPool();
Runnable task = new Runnable() {
@Override
public void run() {
while (true) {
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println(Thread.currentThread().getName());
}
}
};
pool.execute(task);
pool.execute(task);
pool.execute(task);

	3 创建独立任务的线程池

     
     
     
     

      
      
      
      
1
     
     
     
     

ExecutorService pool = Executors.newSingleThreadExecutor();
Runnable task = new Runnable() {
@Override
public void run() {
while (true) {
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println(Thread.currentThread().getName());
}
}
};
pool.execute(task);
pool.execute(task);
pool.execute(task);

	4 创建可调度的线程池

     
     
     
     

      
      
      
      
1
     
     
     
     

ScheduledExecutorService threadPool = Executors.newScheduledThreadPool(2);
Runnable task = new Runnable() {
@Override
public void run() {
while (true) {
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println(Thread.currentThread().getName());
}
}
};
threadPool.schedule(task, 2000, TimeUnit.MILLISECONDS);