线程中级篇(一)：基本并发容器

传统的容器并没有实现线程安全，所以在多线程的情况下，并不管用。本文首先自己手写一个并发Queue引出全文：

import java.util.LinkedList;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;

public class MyQueue {
    
    //1 需要一个承装元素的集合 
    private LinkedList<Object> list = new LinkedList<Object>();
    
    //2 需要一个计数器
    private AtomicInteger count = new AtomicInteger(0);
    
    //3 需要制定上限和下限
    private final int minSize = 0;
    
    private final int maxSize ;
    
    //4 构造方法
    public MyQueue(int size){
        this.maxSize = size;
    }
    
    //5 初始化一个对象 用于加锁
    private final Object lock = new Object();
    
    
    //put(anObject): 把anObject加到BlockingQueue里,如果BlockQueue没有空间,则调用此方法的线程被阻断，直到BlockingQueue里面有空间再继续.
    public void put(Object obj){
        synchronized (lock) {
            while(count.get() == this.maxSize){
                try {
                    lock.wait();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
            //1 加入元素
            list.add(obj);
            //2 计数器累加
            count.incrementAndGet();
            //3 通知另外一个线程（唤醒）
            lock.notify();
            System.out.println("新加入的元素为:" + obj);
        }
    }
    
    
    //take: 取走BlockingQueue里排在首位的对象,若BlockingQueue为空,阻断进入等待状态直到BlockingQueue有新的数据被加入.
    public Object take(){
        Object ret = null;
        synchronized (lock) {
            while(count.get() == this.minSize){
                try {
                    lock.wait();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
            //1 做移除元素操作
            ret = list.removeFirst();
            //2 计数器递减
            count.decrementAndGet();
            //3 唤醒另外一个线程
            lock.notify();
        }
        return ret;
    }
    
    public int getSize(){
        return this.count.get();
    }
    
    
    public static void main(String[] args) {
        
        final MyQueue mq = new MyQueue(5);
        mq.put("a");
        mq.put("b");
        mq.put("c");
        mq.put("d");
        mq.put("e");
        
        System.out.println("当前容器的长度:" + mq.getSize());
        
        Thread t1 = new Thread(new Runnable() {
            @Override
            public void run() {
                mq.put("f");
                mq.put("g");
            }
        },"t1");
        
        t1.start();
        
        
        Thread t2 = new Thread(new Runnable() {
            @Override
            public void run() {
                Object o1 = mq.take();
                System.out.println("移除的元素为:" + o1);
                Object o2 = mq.take();
                System.out.println("移除的元素为:" + o2);
            }
        },"t2");
        
        
        try {
            TimeUnit.SECONDS.sleep(2);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        
        t2.start();
        
        
    }
}

并发类容器是java.util.concurrent包中提供的用于并发编程的容器，主要有以下大类：

package com.xushu.multi;

import java.util.Vector;

public class Ticket {

    public static void main(String[] args) {
        final Vector<String> tickets = new Vector<String>();
        
        for(int i = 1; i < 1000; i++){
            tickets.add("火车票" + i);
        }
        
        for(int i = 1; i <= 10; i++){
            new Thread("线程" + i){
                public void run() {
                    while(true){
                        if(tickets.isEmpty())
                            break;
                        System.out.println(Thread.currentThread().getName() + "---" + tickets.remove(0));
                    }
                }
            }.start();
        }
    }
}

DelayQueue的演示
WangMing.java

package com.xushu.multi;

import java.util.concurrent.Delayed;
import java.util.concurrent.TimeUnit;

public class WangMing implements Delayed{
    
    private String name;
    //身份证
    private String id;
    //截止时间
    private long endTime;
    
    //定义时间工具类
    private TimeUnit timeUnit = TimeUnit.SECONDS;
    
    public WangMing(String name, String id, Long endTime){
        this.name = name;
        this.id = id;
        this.endTime = endTime;
    }
    

    public String getName(){
        return this.name;
    }
    
    public String getId(){
        return this.id;
    }
    
    
    
    @Override
    public int compareTo(Delayed o) {
        WangMing w = (WangMing)o;
        return this.getDelay(this.timeUnit) - w.getDelay(this.timeUnit) > 0 ? 1 : 0;
    }
    
    /**
     * 用来判断是否到了截止时间
     */
    @Override
    public long getDelay(TimeUnit unit) {
        return endTime - System.currentTimeMillis();
    }
    
    
}

WangBa.java

package com.xushu.multi;

import java.util.concurrent.DelayQueue;

public class WangBa implements Runnable{

    private DelayQueue<WangMing> queue = new DelayQueue<WangMing>();
    
    public boolean yinye = true;
    
    public void shangji(String name,String id,int money){  
        WangMing man = new WangMing(name, id, 1000 * money + System.currentTimeMillis());  
        System.out.println("网名"+man.getName()+" 身份证"+man.getId()+"交钱"+money+"块,开始上机...");  
        this.queue.add(man);  
    }  
      
    public void xiaji(WangMing man){  
        System.out.println("网名"+man.getName()+" 身份证"+man.getId()+"时间到下机...");  
    }  
    
    @Override
    public void run() {
        while(yinye){
            WangMing man;
            try {
                man = queue.take();
                xiaji(man);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            
        }
    }
    
    public static void main(String[] args) {
        try{  
            System.out.println("网吧开始营业");  
            WangBa speed = new WangBa();  
            Thread shangwang = new Thread(speed);  
            shangwang.start();  
              
            speed.shangji("路人甲", "123", 1);  
            speed.shangji("路人乙", "234", 10);  
            speed.shangji("路人丙", "345", 5);  
        }  
        catch(Exception e){  
            e.printStackTrace();
        }  
    }

}