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  • java Map集合遍历取值的五种方式

    //基于JDK1.8版本以上 lambada函数

    map.forEach((k, v) -> {
      System.out.println("key:value = " + k + “:” + v);
      if (k.equals(“test”)) {
      //map.put(k, JsonUtil.fromJson((String) v, List.class));
      }
    });

    //keySet获取map集合key的集合 然后在遍历key即可

    for(String key:map.keySet()){
      String value = map.get(key).toString();//
      System.out.println(“key:”+key+" vlaue:"+value);
    }

    //Map集合循环遍历方式三 推荐,尤其是容量大时

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

    // Map集合循环遍历方式三 强列推荐,尤其是容量大时

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

    //通过Map.values()遍历所有的value,但不能遍历key

    for(Object m:map.values()){
        System.out.println(m);
    }
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  • 原文地址:https://www.cnblogs.com/q149072205/p/13226176.html
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