Map的四种遍历方式~

Map<String, String> map = new HashMap<>();
        map.put("110","匪警");map.put("120","医院");map.put("119","火警");

        System.out.println("方式1：map.keySet()遍历");
        for(String key : map.keySet()){
            System.out.println(key+":"+map.get(key));
        }

        System.out.println("方式2：通过Map.entrySet使用iterator遍历");
        Iterator<Map.Entry<String, String>> iterator = map.entrySet().iterator();
        while(iterator.hasNext()){
            Map.Entry<String, String> next = iterator.next();
            System.out.println(next.getKey()+":"+next.getValue());
        }

        System.out.println("方式3：通过Map.entrySet遍历");
        for(Map.Entry<String, String> entry : map.entrySet()){
            System.out.println(entry.getKey()+":"+entry.getValue());