如何在Spring中连接文件中的JSON数据？

Question

I have a simple Spring App. In that app I have @Repository which should provide access to JSON file with my data.

@Repository("jsonStorageUserRepository")
public class JsonUserRepository implements UserRepository {

    @Value("${users}")
    private List<User> users;

    @Override
    public User getByCursor(Cursor cursor) {
        return users.get(cursor.getId);
    }
}

My users.json file (storage) in properties folder -

[
    {
        "name": "Bill",
        "registered": true
    },
    {
        "name": "John",
        "registered": true
    }
]

And my DTO class -

public class User implements Serializable {
    private boolean registered;
    private String name;

    public User(String name, boolean redistricted) {
        this.name = name;
        registered = redistricted;
    }
    // setters and getters were omitted
}

Right now I have exception:

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'jsonStorageUserRepository': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private java.util.List com.springapp.mvc.repository.json.JsonUserRepository.users; nested exception is java.lang.IllegalArgumentException: Could not resolve placeholder 'users' in string value "${users}"

It related to this line -

@Value("${users}")
private List<User> users;

Is it possible to wire converted List of entities from JSON ?

Answer 1

It will not work reading JSON-format-properties file. You need write your custom property editor. Have a look at that article:

http://christopherhunt-software.blogspot.de/2010/04/spring-propertyeditor-for-json-map-and.html

Answer 2

spring doesn't find your property file:

Could not resolve placeholder 'users' in string value "${users}"

at

@Value("${users}")

Maybe the PropertyPlaceHolderConfigurer is wrong configured.