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", "qq@qq.com");

         // 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);
         }
     }
 }