spring - 构造函数注入和重写嵌套 bean 的父级定义

使用Spring框架进行依赖注入是一种常见的方式，其中构造函数注入和重写嵌套bean的父级定义是两种常用的技术。本文将介绍这两种技术，并通过案例代码来演示它们的用法。

java
public class UserService {
    private UserRepository userRepository;
    public UserService(UserRepository userRepository) {
        this.userRepository = userRepository;
    }
    // other methods
}
public class UserRepository {
    // implementation details
}

xml
    
    
    

java
public class UserService {
    private UserRepository userRepository;
    public UserService(UserRepository userRepository) {
        this.userRepository = userRepository;
    }
    public void saveUser(String username) {
        User user = new User(username);
        userRepository.save(user);
    }
}
public interface UserRepository {
    void save(User user);
}
public class UserRepositoryImpl implements UserRepository {
    public void save(User user) {
        // save user to database
    }
}
public class User {
    private String username;
    public User(String username) {
        this.username = username;
    }
}

xml