如何使用 Jackson 读取 JSON 文件中的多个对象？

Question

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!

Answer 1

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));