java - 如何将 JSON 字符串转换为对象的数组列表

Question

我有 JSON 字符串，从 HTTP 请求接收:

     [  
       {  
      "id":15,
      "title":"1",
      "description":"desc",
      "user_id":152
     },
    {  
      "id":18,
      "title":"2",
      "description":"desc",
      "user_id":152
    },
    {  
      "id":19,
      "title":"tab3",
      "description":"zadanka",
      "user_id":152
   }
]

如何将其转换为对象的 ArrayList？

Answer 1

使用 Gson

Gson gson = new Gson();
        ArrayList<Object> listFromGson = gson.fromJson("json string",
               new TypeToken<ArrayList<Object>>() {}.getType());

使用 jackson

    ObjectMapper mapper = new ObjectMapper();
    ArrayList<Object> listFromJackson = mapper.readValue("json string",
           new TypeReference<ArrayList<Object>>(){});

如果你可以将一个 pojo 定义为

public class Example {

    private Integer id;
    private String title;
    private String description;
    private Integer userId;
    // setters / getters
}

然后

ArrayList<Example> listFromGson = gson.fromJson("json string",
               new TypeToken<ArrayList<Example>>() {}.getType());

ArrayList<Example> listFromJackson = mapper.readValue("json string",
               new TypeReference<ArrayList<Example>>(){});

此外，您应该更喜欢使用 List 而不是 ArrayList。