类InheritableThreadLocal的使用

使用类InheritableThreadLocal可以在子线程中取得父线程继承下来的值。

看栗子：

public class Tools {
    public static InheritableThreadLocalExt t1=new InheritableThreadLocalExt();
}

public class InheritableThreadLocalExt extends InheritableThreadLocal{
    @Override
    protected Object initialValue() {
        return new Date().getTime();
    }
}

public class ThreadA extends Thread{
    @Override
    public void run() {
        try{
            for(int i=0;i<10;i++){
                System.out.println("在ThreadA线程中取值 ="+Tools.t1.get());
                Thread.sleep(100);
            }
        }catch (InterruptedException e){
            e.printStackTrace();
        }
    }
}

public class Run {
    public static void main(String[] args){
        try{
            for(int i=0;i<10;i++){
                System.out.println(" 在Main线程中取值="+Tools.t1.get());
                Thread.sleep(100);
            }
            Thread.sleep(5000);
            ThreadA a=new ThreadA();
            a.start();
        }catch (InterruptedException e){
            e.printStackTrace();
        }
    }
}

可以通过重写childValue方法在继承的同时对值进行进一步的处理

public class InheritableThreadLocalExt extends InheritableThreadLocal{
    @Override
    protected Object initialValue() {
        return new Date().getTime();
    }

    @Override
    protected Object childValue(Object parentValue) {
        return parentValue+"我在子线程加的~";
    }
}