原理 https://blog.csdn.net/a837199685/article/details/52712547
例子https://www.cnblogs.com/sweetchildomine/p/8807059.html
public class Test { static ExecutorService executorService = Executors.newFixedThreadPool(1); public static void main(String[] args) { //子线程每次new 所以会复制线程的InheritableThreadLocal,结果正确 // withoutThreadPool(10);//true //因线程池复用线程,不会每次new 所以不会更新父线程InheritableThreadLocal 的值,导致结果错误 withThreadPool(10);//true or false } public static void withoutThreadPool(int c){ for(int i=0;i<c;i++){ Integer var1 = (int)(Math.random()*100); Integer var2 = (int)(Math.random()*100); MyContextHolder.set(var1); threadRun(var1,var2); } } public static void withThreadPool(int c){ for(int i=0;i<c;i++){ Integer var1 = (int)(Math.random()*100); Integer var2 = (int)(Math.random()*100); MyContextHolder.set(var1); threadPoolExecute(var1,var2); } } public static void threadRun(Integer var1,Integer var2){ new Thread(()->assert1(var1,var2)).start(); } public static void threadPoolExecute(Integer var1,Integer var2){ // executorService.execute(()->assert1(var1,var2)); executorService.execute(TtlRunnable.get(()->assert1(var1,var2)) ); } public static void assert1(Integer var1,Integer var2){ System.out.println(MyContextHolder.get()*var2==var1*var2); } public static class MyContextHolder{ // private static ThreadLocal<Integer> stringThreadLocal = new InheritableThreadLocal<>(); private static ThreadLocal<Integer> stringThreadLocal = new TransmittableThreadLocal<>(); public static void set(Integer data) { stringThreadLocal.set(data); } public static Integer get() { return stringThreadLocal.get(); } } }