List 集合

ArrayList

Map集合

HashMap

案例

Map集合与List的集合

package com.xiaohu.dao;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class DAO1 {
    public Map<String,String> getA() {
         Map<String,String> map = new HashMap<String,String>();
         map.put("sid", "XiaoWang");
         map.put("s", "XiaoWang");
         System.out.println(map.get("sid"));
         System.out.println(map.size());
         return map;
         
    }
    public List<Map<String,String>> getB(){
        List<Map<String,String>> list = new ArrayList<Map<String,String>>();
        Map<String,String> map1 = new HashMap<String,String>();
        map1.put("sname","XiaoWang");
        map1.put("Sid", "100588");
        
        Map<String,String> map2 = new HashMap<String,String>();
        map2.put("sname","XiaoZhang");
        map2.put("Sid", "100598");
        
        Map<String,String> map3 = new HashMap<String,String>();
        map3.put("sname","XiaoZhen");
        map3.put("Sid", "100518");
    
        list.add(map1);
        list.add(map2);
        list.add(map3);
        
        for(int i=0;i<list.size();i++) {
            System.out.println(list.get(i));
        }
        return list;
        
        
    }
    public static void main(String[] args) {
        DAO1 dao = new DAO1();
        dao.getA();
    }
}

迭代器

//        迭代器
//        Iterator<Map<String,String>> it = list.iterator();
//        while(it.hasNext()) {
//            System.out.println(it.next());
//        }