Map集合的四种遍历方式

        Map map = new HashMap();
        map.put("a","java");
        map.put("b","c++");
        map.put("c","php");
        map.put("d","python");
        map.put("e","erlang");

        Set set = map.keySet();

        Iterator it = set.iterator();

        while (it.hasNext()){
            String key = it.next();
            String values = map.get(key);
            System.out.println(key+"=="+values);
        }

        Map map = new HashMap();
        map.put("a","java");
        map.put("b","c++");
        map.put("c","php");
        map.put("d","python");
        map.put("e","erlang");

        Set> set = map.entrySet();

        Iterator> it = set.iterator();

        while (it.hasNext()){
            Map.Entry entry = it.next();
            String key = entry.getKey();
            String value = entry.getValue();
            System.out.println(key+"=="+value);

        }

        Map map = new HashMap();
        map.put("a","java");
        map.put("b","c++");
        map.put("c","php");
        map.put("d","python");
        map.put("e","erlang");

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

        Map map = new HashMap();
        map.put("a","java");
        map.put("b","c++");
        map.put("c","php");
        map.put("d","python");
        map.put("e","erlang");

        for(Map.Entry entry:map.entrySet()){
            System.out.println(entry.getKey()+"=="+entry.getValue());
        }