ThreadLocal实现线程级上下文

一.ThreadLocal测试

 package com.junge.threadlocal.context;

 /**
  * @author Administrator
  *
  */
 public class ThreadScopeData {
     private ThreadScopeData() {

     }

     private static ThreadLocal<ThreadScopeData> threadLocal = new ThreadLocal<ThreadScopeData>();

     public static ThreadScopeData getInstance() {
         if (null == threadLocal.get()) {
             threadLocal.set(new ThreadScopeData());
         }

         return threadLocal.get();
     }

     public static void main(String[] args) {

         new Thread(new Runnable() {
             @Override
             public void run() {
                 System.out.println(ThreadScopeData.getInstance());

             }
         }).start();

         new Thread(new Runnable() {
             @Override
             public void run() {
                 System.out.println(ThreadScopeData.getInstance());

             }
         }).start();
     }
 }

二.对上下接口进行封装，使用方便（线程绑定不同的业务数据，线程之间的业务数据放在上下文中）

1.上下文接口ThreadContext

package com.junge.threadlocal.context;

import java.util.Map;

/**
 * 线程上下文接口
 *
 * @author Administrator
 *
 */
public interface ThreadContext {

    /**
     * 保持用户名
     *
     * @param userName
     */
    void setUserName(String userName);

    /**
     * 获取用户名
     *
     * @return
     */
    String getUserName();

    /**
     * 保持参数1
     *
     * @param param
     */
    void setParam1(Object param);

    /**
     * 获取参数1
     *
     * @return
     */
    Object getParam1();

    /**
     * 添加参数
     *
     * @param key
     * @param param
     */
    void addParam(String key, Object param);

    /**
     * 获取参数
     *
     * @param key
     * @return
     */
    Object getParam(String key);

    /**
     * 获取所有添加的参数
     *
     * @return
     */
    Map<String, Object> getAllParam();
}

2.线程上下文接口实现ThreadContextImpl

package com.junge.threadlocal.context;

import java.util.HashMap;
import java.util.Map;

/**
 * 线程上下文接口实现
 *
 * @author Administrator
 *
 */
public class ThreadContextImpl implements ThreadContext {

    private String userName;

    private Object param1;

    private Map<String, Object> paramMap;

    @Override
    public void setUserName(String userName) {
        this.userName = userName;

    }

    @Override
    public String getUserName() {

        return this.userName;
    }

    @Override
    public void setParam1(Object param) {
        this.param1 = param;

    }

    @Override
    public Object getParam1() {

        return param1;
    }

    /*
     * (non-Javadoc)
     *
     * @see
     * com.junge.threadlocal.context.ThreadContext#addParam(java.lang.String,
     * java.lang.Object)
     */
    @Override
    public void addParam(String key, Object param) {
        if (null == paramMap) {
            paramMap = new HashMap<String, Object>();
        }

        paramMap.put(key, param);

    }

    /*
     * (non-Javadoc)
     *
     * @see
     * com.junge.threadlocal.context.ThreadContext#getParam(java.lang.String)
     */
    @Override
    public Object getParam(String key) {
        if (null == paramMap) {
            paramMap = new HashMap<String, Object>();
        }
        return paramMap.get(key);
    }

    /*
     * (non-Javadoc)
     *
     * @see com.junge.threadlocal.context.ThreadContext#getAllParam()
     */
    @Override
    public Map<String, Object> getAllParam() {
        if (null == paramMap) {
            paramMap = new HashMap<String, Object>();
        }
        return paramMap;
    }

}

3.线程上下文助手ThreadContextHolder

 /**
  *
  */
 package com.junge.threadlocal.context;

 import java.util.Map;

 /**
  * 线程上下文助手
  *
  * @author Administrator
  *
  */
 public class ThreadContextHolder {

     /**
      * 上下文保持对象
      */
     private static ThreadLocal<ThreadContext> threadContext = new ThreadLocal<ThreadContext>();

     public static void setThreadContext(ThreadContext context) {
         threadContext.set(context);
     }

     public static ThreadContext getThreadContext() {
         if (null == threadContext.get()) {
             threadContext.set(new ThreadContextImpl());
         }
         return threadContext.get();
     }

     public static void setUserName(String userName) {
         getThreadContext().setUserName(userName);
     }

     public static String getUserName() {
         return getThreadContext().getUserName();
     }

     public static void setParam1(Object param) {
         getThreadContext().setParam1(param);
     }

     public static Object getParam1() {
         return getThreadContext().getParam1();
     }

     public static void addParam(String key, Object param) {
         getThreadContext().addParam(key, param);
     }

     public static Object getParam(String key) {
         return getThreadContext().getParam(key);
     }

     public static Map<String, Object> getAllParam() {
         return getThreadContext().getAllParam();
     }

 }

4.线程上下文测试代码

 package com.junge.threadlocal.context;

 public class ThreadContextHolderTest {

     /**
      * @param args
      */
     public static void main(String[] args) {
         new Thread(new Runnable() {
             @Override
             public void run() {
                 ThreadContextHolder.setUserName("userName1");
                 ThreadContextHolder.setParam1(new Object());
                 ThreadContextHolder.addParam("param1", "aaaa");

                 System.out.println(Thread.currentThread().getName() + ":"
                         + ThreadContextHolder.getUserName());
                 System.out.println(Thread.currentThread().getName() + ":"
                         + ThreadContextHolder.getParam1());
                 System.out.println(Thread.currentThread().getName() + ":"
                         + ThreadContextHolder.getParam("param1"));

             }
         }).start();

         new Thread(new Runnable() {
             @Override
             public void run() {
                 ThreadContextHolder.setUserName("userName2");
                 ThreadContextHolder.setParam1(new Object());
                 ThreadContextHolder.addParam("param1", "bbbb");

                 System.out.println(Thread.currentThread().getName() + ":"
                         + ThreadContextHolder.getUserName());
                 System.out.println(Thread.currentThread().getName() + ":"
                         + ThreadContextHolder.getParam1());
                 System.out.println(Thread.currentThread().getName() + ":"
                         + ThreadContextHolder.getParam("param1"));

             }
         }).start();

     }

 }
运行结果：
Thread-0:userName1
Thread-0:java.lang.Object@6e1408
Thread-0:aaaa
Thread-1:userName2
Thread-1:java.lang.Object@e53108
Thread-1:bbbb