java遍历map集合的几种方式

1

{
    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<>();
        map2.put("11", "aa");
        map2.put("22", "bb");
        map2.put("33", "cc");
        listMaps.add(map2);

        for (Map<String, Object> map : listMaps) {
            //map.keySet() 获取map集合对象
            for(String s : map.keySet()) {
                System.out.print(map.get(s));
            }
        }

        for(int i = 0; i < listMaps.size(); i++){
            Map<String, Object> map = listMaps.get(i);
            Iterator<String> iterator = map.keySet().iterator();
            while (iterator.hasNext()){
                String string = (String) iterator.next();
//                System.out.print(map.get(string));
                System.out.print(string + "-->" + map.get(string) + "|");
            }
        }

        System.out.println("=================");
        for (Map<String, Object> map : listMaps){
            //Entry内部类来表示一个映射项，映射项包含Key和Value
            for (Map.Entry<String, Object> m : map.entrySet()){
                System.out.print(m.getKey() + "-->" + m.getValue() + "|");
            }
        }

        System.out.println("-----------------------------------");
        String a = "proming";
        String b = new String("proming");
        System.out.println(a == b);
        String c = "min";
        String d = "proming" + "min";
        String e = a + c ;
        System.out.println(d == e);

    }
}