循环遍历map集合的五种方式，含java8

循环遍历map，以下为要遍历的map

 

 Map<String, String> maps = new HashMap<>();
  maps.put("1","aaa");
  maps.put("2","bbb");
  maps.put("3","bbb");

1.通过遍历key集合，取出对应的key,value

 

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

2.iterator遍历

 

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

3.entryset遍历，可直接取出key,value

 

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

4.只需要value的时候，遍历values即可

 

for(String value : maps.values()){
      System.out.println("value: "+value);
}

5.java8

 

maps.forEach((k,v)->{
    System.out.println("key: "+k+" value: "+v);
 });

欢迎补充！