遍历map

最新推荐文章于 2023-11-27 17:04:39 发布

转载最新推荐文章于 2023-11-27 17:04:39 发布 · 166 阅读

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CC 4.0 BY-SA版权

原文链接：http://www.cnblogs.com/flywang/p/7838301.html

文章标签：

#java

本文展示了一种使用Java遍历List中Map集合的方法，通过三种不同方式实现，包括使用增强for循环、普通for循环结合迭代器，以及利用Map的entrySet进行遍历。

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
public class Test {
   public static void main(String[] args) {

       List<Map<String, Object>> listMaps = new ArrayList<Map<String, Object>>();

       Map<String, Object> map1 = new HashMap<String, Object>();
       map1.put("1", "a");
       map1.put("2", "b");
       map1.put("3", "c");
       listMaps.add(map1);

       Map<String, Object> map2 = new HashMap<String, Object>();
       map2.put("11", "aa");
       map2.put("22", "bb");
       map2.put("33", "cc");
       listMaps.add(map2);

       for (Map<String, Object> map : listMaps) {
           for (String s : map.keySet()) {
               System.out.print(map.get(s) + " ");
           }
       }
       System.out.println();
       System.out.println("========================");
       for (int i = 0; i < listMaps.size(); i++) {
           Map<String, Object> map = listMaps.get(i);
           Iterator iterator = map.keySet().iterator();
           while (iterator.hasNext()) {
               String string = (String) iterator.next();
               System.out.println(map.get(string));
           }
       }
       System.out.println("++++++++++++++++++++++++++++");
       for (Map<String, Object> map : listMaps) {
           for (Map.Entry<String, Object> m : map.entrySet()) {
               System.out.print(m.getKey() + "    ");
               System.out.println(m.getValue());
           }
       }
       System.out.println("-----------------------------");
   }

}

打印的结果：

c b a bb cc aa
========================
c
b
a
bb
cc
aa
++++++++++++++++++++++++++++
3    c
2    b
1    a
22    bb
33    cc
11    aa
-----------------------------

转载于:https://www.cnblogs.com/flywang/p/7838301.html