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);
        }
    }
}