只写效率高的，效率低的遍历就不写了！！
先创建HashMap

 Map<String,String> mapOne = new HashMap<>();mapOne.put("name","wyp");mapOne.put("sex","男");

一.使用Iterator

 Iterator<Map.Entry<String,String>> entryInterator = mapOne.entrySet().iterator();while (entryInterator.hasNext()){Map.Entry<String,String> next = entryInterator.next();System.out.println("key:"+next.getKey()+" value"+next.getValue());}

结果如下

二.使用ForEach

for(Map.Entry<String,String> map:mapOne.entrySet()){System.out.println("key:"+map.getKey()+" value"+map.getValue());}

结果如下