java线程之InheritableThreadLocal

最新推荐文章于 2025-03-04 00:03:21 发布

houzhizhen

最新推荐文章于 2025-03-04 00:03:21 发布

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本文通过代码示例展示了ThreadLocal与InheritableThreadLocal的区别：前者在线程间不传递值，而后者可以将值从父线程传递给子线程。通过具体的输出结果直观地解释了这两种类的行为差异。

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hreadLocal和InheritableThreadLocal区别，可以用代码测试一下：

在CODE上查看代码片派生到我的代码片

    package com.lang;  

    import junit.framework.TestCase;  

    import static java.lang.System.out;  

    public class TestInheritableThreadLocal extends TestCase {  

        public void testThreadLocal() {  
            final ThreadLocal<String> local = new ThreadLocal<String>();  
            work(local);  
        }  

        public void testInheritableThreadLocal() {  
            final ThreadLocal<String> local = new InheritableThreadLocal<String>();  
            work(local);  
        }  

        private void work(final ThreadLocal<String> local) {  
            local.set("a");  
            out.println(Thread.currentThread() + "," + local.get());  
            Thread t = new Thread(new Runnable() {  

                @Override  
                public void run() {  
                    out.println(Thread.currentThread() + "," + local.get());  
                    local.set("b");  
                    out.println(Thread.currentThread() + "," + local.get());  
                }  
            });  

            t.start();  
            try {  
                t.join();  
            } catch (InterruptedException e) {  
                e.printStackTrace();  
            }  

            out.println(Thread.currentThread() + "," + local.get());  
        }  
    }

运行testThreadLocal，输出：

    Thread[main,5,main],a  
    Thread[Thread-0,5,main],null  
    Thread[Thread-0,5,main],b  
    Thread[main,5,main],a

运行testInheritableThreadLocal，输出：

    Thread[main,5,main],a  
    Thread[Thread-0,5,main],a  
    Thread[Thread-0,5,main],b  
    Thread[main,5,main],a

比较后，看到ThreadLocal里的值，子线程里不能获得；InheritableThreadLocal里的值，子线程可以获得。