Java.lang InheritableThreadLocal

1 Java.lang InheritableThreadLocal介绍

java.lang.InheritableThreadLocal 类扩展了ThreadLocal从父线程提供的值来继承子线程：创建一个子线程的时候，子的所有可继承线程局部变量可以是其父有接收值的初始值。

2 Java.lang InheritableThreadLocal声明

public class InheritableThreadLocal<T>
   extends ThreadLocal<T>

3 Java.lang InheritableThreadLocal方法

4 Java.lang InheritableThreadLocal案例

package com.yiidian;

/**
 * 一点教程网： http://www.yiidian.com
 */
// Java program to illustrate inheritance of customized value 
// from parent thread to child thread 
  
class ParentThread extends Thread { 
    // anonymous inner class  for overriding childValue method. 
    public static InheritableThreadLocal gfg_tl = new InheritableThreadLocal() { 
        public Object childValue(Object parentValue) 
        { 
            return "child data"; 
        } 
    }; 
    public void run() 
    { 
        // setting the new value 
        gfg_tl.set("parent data"); 
        // parent data 
        System.out.println("Parent Thread Value :" + gfg_tl.get()); 
  
        ChildThread gfg_ct = new ChildThread(); 
        gfg_ct.start(); 
    } 
} 
class ChildThread extends Thread { 
  
    public void run() 
    { 
        // child data 
        System.out.println("Child Thread Value :" + ParentThread.gfg_tl.get()); 
    } 
} 
class ThreadLocalDemo { 
  
    public static void main(String[] args) 
    { 
        ParentThread gfg_pt = new ParentThread(); 
        gfg_pt.start(); 
    } 
} 

输出结果为：

Parent Thread Value:parent data 
Child Thread Value:child data