Map加锁操作小例子
所谓加锁，即对一些公用的资源操作的时候进行锁定，操作完之后释放，写个小例子：
package com.tycyjd.action;import java.util.HashMap;import java.util.Map;public class MyTest {private static Map<String, Object> map = new HashMap<String, Object>();private static Map<String, Object> preMap = new HashMap<String, Object>();// 加锁机制public static synchronized boolean setCartMap(Map<String, Object> checkMap) {preMap = map;System.out.println("oldMap:" + map.toString());for (Map.Entry<String, Object> entry : checkMap.entrySet()) {if (null != map.get(entry.getKey())) {map = preMap;System.out.println("newMap:" + map.toString());return false;} else {map.put(entry.getKey(), entry.getValue());}}System.out.println("newMap:" + map.toString());// map.clear();return true;}}