java速度入五._多线程编程基础

首先是线程的创建和jion（）方法的使用。

class Sleeper extends Thread

{

private int sleeptime;

public Sleeper(String name,int sleepTime)

{

super(name);

sleeptime=sleepTime;

start();

}

public void run()

{

try

{

for(int i=0;i<5;i++)

{

System.out.println(getName()+"print"+i);

sleep(sleeptime);

}

}catch(InterruptedException e)

{

System.out.println(getName()+"interrupted");

}

System.out.println(getName()+" over");

}

}

class Joiner extends Thread

{

private Sleeper sleeper;

public Joiner(String name,Sleeper sleeper)

{

super(name);

this.sleeper=sleeper;

start();

}

public void run()

{

try

{

System.out.println(getName()+" Begin");

System.out.println(sleeper.getName()+"begin jion()....");

sleeper.join();

for(int i=5;i>0;i--)

{

System.out.println(getName()+"print:"+i);

}

}catch(Exception e)

{

e.printStackTrace();

}

System.out.println(getName()+"Over!");

}

}

public class SimpleJoin {

public static void main(String[] args)

{

Sleeper sleeper1=new Sleeper("Tread A sleeper1",1500),

sleeper2=new Sleeper("Tread A sleeper2",1000);

Joiner joiner=new Joiner("ThreadB",sleeper2);

sleeper1.interrupt();

//System.out.println("Hello");

}

}

创建三个Tread，第三个jion了第二个。

运行结果：

Tread A sleeper1print0

Tread A sleeper2print0

Tread A sleeper1interrupted

Tread A sleeper1 over

ThreadB Begin

Tread A sleeper2begin jion()....

Tread A sleeper2print1

Tread A sleeper2print2

Tread A sleeper2print3

Tread A sleeper2print4

Tread A sleeper2 over

ThreadBprint:5

ThreadBprint:4

ThreadBprint:3

ThreadBprint:2

ThreadBprint:1

ThreadBOver!

第二个是线程的共享与互斥问题

class Water

{

static Object pool=new Object();

static int total=6; //the volumn of the pool

static int in=3; //the number of water which pool have

static int out=0; //the water drain away

}

class ThreadA extends Thread//drain water class

{

void drain()

{

synchronized(Water.pool)

{

System.out.println("Empty or not?"+isEmpty());

if(isEmpty())

{

try

{

Water.pool.wait();

}catch(InterruptedException e)

{

e.printStackTrace();

}

}

else

{

Water.out++;

System.out.println("Drain out water:"+Water.out);

}

}

}

public void run(){

while(Water.in<Water.total){

if(isEmpty())

System.out.println("Empty");

System.out.println("Drain out water now!");

drain();

try{

sleep(1000);

}catch(InterruptedException e){

e.printStackTrace();

}

}

}

public boolean isEmpty()

{

return Water.in==Water.out?true:false;

}

}

class ThreadB extends Thread{

void jswork(){

synchronized(Water.pool){

Water.in++;

Water.pool.notify();

System.out.println("In :"+Water.in);

}

}

public void run(){

while(Water.in<Water.total){

System.out.println("Empty");

jswork();

try{

sleep(3000);

}catch(InterruptedException e){

e.printStackTrace();

}

}

}

}

public class pool {

public static void main(String[] args)

{

ThreadA threadA=new ThreadA();

ThreadB threadB=new ThreadB();

threadB.start();

threadA.start();

//System.out.println("Hello!");

}

}

java中线程的同步有两种方法。

1.同步方法

synchronized void fun(){}

标记为synchronized的方法，在它执行完之前，其他标记为synchronized的方法都将被阻塞。

2.同步块

synchronized(someobject)

{}

只有拥有运行代码权限的线程才能运行同步块内的代码。

java中的线程通信

主要用到wait()和notify()方法，和操作系统里的p，v操作类似，interrupt()用于终止进程。

例子说明：池塘的类，两个线程，排水和进水，当排水量和进水量相同时，排水量被挂起，直到进水进程注水完成后，才通知排水进程排水。