英文:
How to read multiple objects in a JSON file with Jackson?
问题
我已经编写了一些代码，将 List<Class> 的内容保存到一个 JSON 文件中，大致如下所示：
{ "firstName": "Name", "lastName": "LastName", "Email": "Email" } { "firstName": "Name2", "lastName": "LastName2", "Email": "Email2" }
现在我尝试将此文件输入到我的程序中，程序可以工作，但只返回第一个 JSON 对象。这是我的代码：
ObjectMapper mapper = new ObjectMapper();
JsonNode readFile = mapper.readTree(new File("path/to/file.json"));
我如何读取整个 JSON 文件，以及如何将其内容添加到上述相同的 List 中呢？每个教程等我遇到的都只解释如何使用单个对象。谢谢！
英文:
I have written some code which saves the contents of a List<Class> to a JSON file, which looks kinda like this:
{ "firstName": "Name", "lastName": "LastName", "Email": "Email" } { "firstName": "Name2", "lastName": "LastName2", "Email": "Email2" }
Now I'm trying to input this file into my program, which works but only the first JSON Object is being returned. This is my code:
ObjectMapper mapper = new ObjectMapper();
JsonNode readFile = mapper.readTree(new File("path/to/file.json"));
How can I read the full JSON file and how can I add the contents of it to the same List mentioned above?
Every tutorial etc. I stumble upon only explains this using a single object.
Thank you!
答案1
得分: 0
可以这样做：
创建一个类似这样的用户类：
public class User {
private String email;
private String firstName;
private String lastName;
// 设置器和获取器（Setters and getters）
}
现在你可以这样做：
String json = 你的Json字符串;
ObjectMapper mapper = new ObjectMapper();
User[] userArray = mapper.readValue(json, User[].class);
List<User> userList = Arrays.asList(mapper.readValue(json, User[].class));
英文:
You can do this:
Create a user class like this:
public class User {
private String email;
private String firstName;
private String lastName;
// Setters and getters
}
Now you can do this:
String json = yourJson;
ObjectMapper mapper = new ObjectMapper();
User[] userArray = mapper.readValue(json, User[].class);
List<User> userList = Arrays.asList(mapper.readValue(json, User[].class));
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