总结：
ThreadLocal：set，get 需要再同一个线程中执行，父子线程不支持
InheritableThreadLocal：支持父子线程，不支持线程池
TransmittableThreadLocal :以上都支持

代码示例
1 pom.xml

<!-- 阿里线程传递值 --><dependency><groupId>com.alibaba</groupId><artifactId>transmittable-thread-local</artifactId><version>2.14.3</version></dependency>

2 ThreadLocal，InheritableThreadLocal 对比

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.concurrent.TimeUnit;public class InheritableThreadLocalExample {static Logger logger = LoggerFactory.getLogger(InheritableThreadLocalExample.class);/*** 输出结果*  [main] [traceId:] - userName:张三*  [thread1] [traceId:] - userName:null* @throws InterruptedException*/private static void threadLocalTest() throws InterruptedException {ThreadLocal<String> userNameTL = new ThreadLocal<>();//这里是主线程，ThreadLocal中设置了值：张三userNameTL.set("张三");logger.info("userName:{}", userNameTL.get());//创建了一个子线程thread1，在子线程中去ThreadLocal中拿值，能否拿到刚才放进去的“张三”呢？new Thread(() -> {logger.info("userName:{}", userNameTL.get());}, "thread1").start();TimeUnit.SECONDS.sleep(1);}/*** 输出结果*  [main] [traceId:] - userName:张三*  [thread1] [traceId:] - userName:张三** @throws InterruptedException*/private static void inheritableThreadLocal() throws InterruptedException {InheritableThreadLocal<String> userNameItl = new InheritableThreadLocal<>();//这里是主线程，使用 InheritableThreadLocal.set 放入值：张三userNameItl.set("张三");logger.info("userName:{}", userNameItl.get());//创建了一个子线程thread1，在子线程中去ThreadLocal中拿值，能否拿到刚才放进去的“张三”呢？new Thread(() -> {logger.info("userName:{}", userNameItl.get());}, "thread1").start();TimeUnit.SECONDS.sleep(1);}public static void main(String[] args) throws InterruptedException {threadLocalTest();System.out.println();inheritableThreadLocal();}
}

3 InheritableThreadLocal ，TransmittableThreadLocal  对比

import com.alibaba.ttl.TransmittableThreadLocal;
import com.alibaba.ttl.threadpool.TtlExecutors;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;public class TransmittableThreadLocalExample {static Logger logger = LoggerFactory.getLogger(TransmittableThreadLocalExample.class);/*** 输出结果*  [main] [traceId:] - userName:张三*  [pool-1-thread-1] [traceId:] - 第1次获取 userName:张三*  [main] [traceId:] - userName:李四*  [pool-1-thread-1] [traceId:] - 第2次获取 userName:张三** @throws InterruptedException*/private static void fangfa_Inheri_test() throws InterruptedException {InheritableThreadLocal<String> userNameTtl = new InheritableThreadLocal<String>();// 为了看到效果，这里创建大小为1的线程池，注意这里为1才能方便看到效果ExecutorService executorService = Executors.newFixedThreadPool(1);// 主线程中设置 张三userNameTtl.set("张三");logger.info("userName:{}", userNameTtl.get());// 在线程池中通过 TransmittableThreadLocal 拿值，看看能否拿到 刚才放入的张三？executorService.execute(() -> {logger.info("第1次获取 userName:{}", userNameTtl.get());});TimeUnit.SECONDS.sleep(1);// 这里放入了李四userNameTtl.set("李四");logger.info("userName:{}", userNameTtl.get());// 在线程池中通过 TransmittableThreadLocal 拿值，看看能否拿到 刚才放入的李四？executorService.execute(() -> {// 在线程池中通过 inheritableThreadLocal 拿值，看看能否拿到？logger.info("第2次获取 userName:{}", userNameTtl.get());});TimeUnit.SECONDS.sleep(1);}/*** 输出结果*  [main] [traceId:] - userName:张三*  [pool-1-thread-1] [traceId:] - 第1次获取 userName:张三*  [main] [traceId:] - userName:李四*  [pool-1-thread-1] [traceId:] - 第2次获取 userName:李四** @throws InterruptedException*/private static void fangfa_Transmit_test() throws InterruptedException {TransmittableThreadLocal<String> userNameTtl = new TransmittableThreadLocal<String>();// 为了看到效果，这里创建大小为1的线程池，注意这里为1才能方便看到效果ExecutorService executorService = Executors.newFixedThreadPool(1);// 这里需要用 TtlExecutors.getTtlExecutorService 将原线程池包装下executorService = TtlExecutors.getTtlExecutorService(executorService);// 主线程中设置 张三userNameTtl.set("张三");logger.info("userName:{}", userNameTtl.get());// 在线程池中通过 TransmittableThreadLocal 拿值，看看能否拿到 刚才放入的张三？executorService.execute(() -> {logger.info("第1次获取 userName:{}", userNameTtl.get());});TimeUnit.SECONDS.sleep(1);// 这里放入了李四userNameTtl.set("李四");logger.info("userName:{}", userNameTtl.get());// 在线程池中通过 TransmittableThreadLocal 拿值，看看能否拿到 刚才放入的李四？executorService.execute(() -> {// 在线程池中通过 inheritableThreadLocal 拿值，看看能否拿到？logger.info("第2次获取 userName:{}", userNameTtl.get());});TimeUnit.SECONDS.sleep(1);}public static void main(String[] args) throws InterruptedException {fangfa_Inheri_test();System.out.println();fangfa_Transmit_test();}
}