Java中的ThreadLocal功能演示示例

package com.fun.ztest.java;

import com.fun.frame.SourceCode;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;

/**
 * ThreadLocal演示测试类
 */
public class FunTester extends SourceCode {

  public static Logger logger = LoggerFactory.getLogger(FunTester.class);

  /**
   * 这个是重点,通过ThreadLocal类重建线程私有的对象
   */
  private static final ThreadLocal format = new ThreadLocal() {

    @Override
    protected Object initialValue() {
      Object funTester = new Object();
      logger.info("初始化对象,线程: {} 对象: {}", Thread.currentThread().getName(), funTester.hashCode());
      return funTester;
    }
  };

  public static void main(String args[]) throws IOException, InterruptedException {
    for (int i = 0; i <5; i++) {
      Thread t = new Thread(new Fun());
      t.start();
    }
  }

  /**
   * 获取对象
   *
   * @return
   */
  public static Object get() {
    return format.get();
  }


  static class Fun implements Runnable {

    @Override
    public void run() {
      logger.info("线程: {} 对象: {}", Thread.currentThread().getName(), FunTester.get().hashCode());
    }


  }


}

INFO-> 当前用户：fv，IP：10.60.193.37，工作目录：/Users/fv/Documents/workspace/fun/,系统编码格式:UTF-8,系统Mac OS X版本:10.16
INFO-> 初始化对象,线程: Thread-1 对象: 347384150
INFO-> 初始化对象,线程: Thread-2 对象: 142607688
INFO-> 线程: Thread-1 对象: 347384150
INFO-> 线程: Thread-2 对象: 142607688
INFO-> 初始化对象,线程: Thread-3 对象: 1008357237
INFO-> 初始化对象,线程: Thread-4 对象: 559951532
INFO-> 线程: Thread-3 对象: 1008357237
INFO-> 线程: Thread-4 对象: 559951532
INFO-> 初始化对象,线程: Thread-5 对象: 748958847
INFO-> 线程: Thread-5 对象: 748958847

Process finished with exit code 0

public class TraceKeyHolder {
  private static ThreadLocal threadLocal = new ThreadLocal();

  public TraceKeyHolder() {
  }

  public static String getTraceKey() {
    return (String)threadLocal.get();
  }

  public static void setTraceKey(String traceKey) {
    threadLocal.set(traceKey);
  }

  public static void clear() {
    threadLocal.remove();
  }
}