java 线程 学习笔记

1.创建

Thread thread = new Thread(task); //task为一个实现Runnable接口的任务实例

2.开始

thread.start();

3.线程池

ExecutorService executor = Executor.newFixedThreadPool(3);//创建一个最大线程数为3的线程池

executor.execute(任务1);

executor.execute(任务2);

executor.shutdown();//不再接受新任务，但会把当前的做完

4.synchronized关键字

synchronized(account){

account.deposit(1);

}

或者 public synchronized void deposit(double amount)在方法中加

5.利用加锁同步

• private static Lock lock=new ReentrantLock();
• private static Condition newDeposit=lock.newCondition();
• //一个条件对应一个锁
• lock.lock();获取锁
• newDeposit().await();//让存款任务进入休眠,等待sign
• newDeposit().signAll();//通知所有该条件的等待进程
• lock.unlock();释放锁
• 注意：条件是由锁创建的，为了调用条件的方法，必须首先拥有锁！！！

public class ThreadCooperation {private static Account2 account=new Account2();public static void main(String []args){ExecutorService executor=Executors.newFixedThreadPool(2);executor.execute(new DepositTask());executor.execute(new WithdrawTask());executor.shutdown();System.out.println("Thread 1\t\tThread 2\t\tBalance");}public static class DepositTask implements Runnable{@Overridepublic void run() {// TODO Auto-generated method stubtry{while(true){account.deposit((int)(Math.random()*10)+1);Thread.sleep(1000);}}catch(Exception e){e.printStackTrace();}}}public static class WithdrawTask implements Runnable{@Overridepublic void run() {// TODO Auto-generated method stubwhile(true){account.withdraw((int)(Math.random()*10+1));}}}}class Account2{private int balance=0;private static Lock lock=new ReentrantLock();private static Condition newDeposit=lock.newCondition();public int getBalance(){return balance;}public void withdraw(int amount){lock.lock();try{while(balance<amount){System.out.println("\t\t\tWait for a deposit");newDeposit.await();}balance-=amount;System.out.println("\t\t\tWithdraw "+amount+"\t\t"+getBalance());}catch(Exception e){e.printStackTrace();}finally{lock.unlock();}}public void deposit(int amount){lock.lock();balance+=amount;System.out.println("Deposit "+amount+"\t\t\t\t\t"+getBalance());newDeposit.signalAll();lock.unlock();}}