本例子主要目的鳍怨，給每個(gè)線程賦予單獨(dú)的變量副本呻右，使各線程之間不互相影響

/**
 * @Package: com.example.thread
 * @Description: 序列號生成器
 * @author: liuxin
 * @date: 17/3/31 下午1:50
 */
public interface Sequence {
    int getNumber();
}

/**
 * @Package: com.example.thread
 * @Description: 每個(gè)線程調(diào)用都會刷新值去覆蓋，所以鞋喇，所有線程共同消費(fèi)number
 * @author: liuxin
 * @date: 17/3/31 下午1:51
 */
public class SequenceA implements Sequence {
    private static volatile  int number=0;
    @Override
    public int getNumber() {
        number=number+1;
        return number;
    }
}

/**
 * @Package: com.example.thread
 * @Description: 局部線程變量池声滥，每個(gè)線程使用自己的，所以各個(gè)線程之間不共享
 * @author: liuxin
 * @date: 17/3/31 下午1:58
 */
public class SequenceB implements Sequence {

    /**
     * 當(dāng)使用ThreadLocal維護(hù)變量時(shí)侦香，ThreadLocal為每個(gè)使用該變量的線程提供獨(dú)立的變量副本落塑，
     * 所以每一個(gè)線程都可以獨(dú)立地改變自己的副本，而不會影響其它線程所對應(yīng)的副本罐韩。
     * 從線程的角度看憾赁，目標(biāo)變量就象是線程的本地變量，這也是類名中“Local”所要表達(dá)的意思散吵。
     */
    private static ThreadLocal<Integer> numberContainer = new ThreadLocal<Integer>() {
        @Override
        protected Integer initialValue() {
            return 0;
        }
    };

    @Override
    public int getNumber() {
        numberContainer.set(numberContainer.get() + 1);
        return numberContainer.get();
    }
}

/**
 * @Package: com.example.thread
 * @Description: 多線程
 * @author: liuxin
 * @date: 17/3/23 下午4:35
 */
public class MyThread extends Thread {
    Sequence sequence;

    MyThread(Sequence sequence) {
        this.sequence = sequence;
    }

    @Override
    public void run() {
        for (int i = 0; i < 3; i++) {
            System.out.println(Thread.currentThread().getName() + "<---->" + sequence.getNumber());
        }
    }

    public static void main(String[] args) {

        Sequence sequence = new SequenceA();
        MyThread t0 = new MyThread(sequence);
        MyThread t1 = new MyThread(sequence);
        MyThread t2 = new MyThread(sequence);
        t0.start();t0.setPriority(10);
        t1.start();t1.setPriority(9);
        t2.start();t2.setPriority(8);


        Sequence sequence1 = new SequenceB();
        MyThread t3 = new MyThread(sequence1);
        MyThread t4 = new MyThread(sequence1);
        MyThread t5 = new MyThread(sequence1);
        t3.start();t3.setPriority(7);
        t4.start();t4.setPriority(6);
        t5.start();t5.setPriority(5);


    }
}
        Thread-0<---->1
        Thread-0<---->2
        Thread-0<---->3
        Thread-1<---->4
        Thread-1<---->5
        Thread-1<---->6
        Thread-2<---->7
        Thread-2<---->8
        Thread-2<---->9
        Thread-3<---->1
        Thread-4<---->1
        Thread-3<---->2
        Thread-5<---->1
        Thread-3<---->3
        Thread-4<---->2
        Thread-5<---->2
        Thread-5<---->3
        Thread-4<---->3

自定義一個(gè)ThreadLocal龙考，設(shè)計(jì)思路就是為每個(gè)線程保存一個(gè)變量副本
使用Map實(shí)現(xiàn)

import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

/**
 * @Package: com.example.thread
 * @Description: 手動實(shí)現(xiàn)一個(gè)TheadLocal
 * @author: liuxin
 * @date: 17/3/31 下午2:22
 */
public class MyTheadLocal<T> {
    private Map<Thread, T> container = Collections.synchronizedMap(new HashMap<Thread, T>());
    
    public void set(T value){
        container.put(Thread.currentThread(),value);
    }
    
    public T get(){
       return container.get(Thread.currentThread());
    }
    
    public void remove(){
        container.remove(Thread.currentThread());
    }
    
    protected T initialValue(){
        return null;
    }
}