java map 遍历

转自http://rain-2372.iteye.com/blog/1615615

 package com.spring.test_B11_aop1;

 import java.util.HashMap;

 import java.util.Iterator;

 import java.util.Map;

 import java.util.Set;

 public class MapTest {

     public static void main(String[] args) {

         // java中遍历MAP的几种方法

         // Java代码

         Map<String, String> map = new HashMap<String, String>();

         map.put("username", "qq");

         map.put("passWord", "123");

         map.put("userID", "1");

         map.put("email", "[email protected]");

         // 第一种用for循环

         // Java代码

         for (Map.Entry<String, String> entry : map.entrySet()) {

             System.out.println(entry.getKey() + "--->" + entry.getValue());

         }

         // 第二种用迭代

         // Java代码

         Set<?> set = map.entrySet();

         Iterator<?> i = set.iterator();

         while (i.hasNext()) {

             @SuppressWarnings("unchecked")

             Map.Entry<String, String> entry1 = (Map.Entry<String, String>) i.next();

             System.out.println(entry1.getKey() + "==" + entry1.getValue());

         }

         // 用keySet()迭代

         // Java代码

         Iterator<String> it = map.keySet().iterator();

         while (it.hasNext()) {

             String key;

             String value;

             key = it.next().toString();

             value = map.get(key);

             System.out.println(key + "--" + value);

         }

         // 用entrySet()迭代

         // Java代码

         Iterator<?> it2 = map.entrySet().iterator();

         System.out.println(map.entrySet().size());

         String key;

         String value;

         while (it2.hasNext()) {

             @SuppressWarnings("rawtypes")

             Map.Entry entry = (Map.Entry) it2.next();

             key = entry.getKey().toString();

             value = entry.getValue().toString();

             System.out.println(key + "====" + value);

         }

     }

 }