Springboot's Java configuration method (example explanation)

1. Create the User entity class.

 @Datapublic class User { private String username; private String password; private Integer age;}

2. Create UserDao to simulate database interaction.

 public class UserDao{ public List<User> queryUserList() { List<User> result = new ArrayList<User>(); //Simulate database query for(int i = 1;i < 10; i++) { User user = new User(); user.setUsername("username_" + i); user.setPassword("password" + i); user.setAge(i); result.add(user); } return result; }}

3. Write UserService to implement the business logic of User data operation.

 @servicepublic class UserService{ @Autowired//Inject the bean object private UserDao userDao; public List<User> queryUserList() { //Calling the method in userDao for query. return this.userDao.queryUserList(); } }

4. Write SpringConfig for instantiating Spring containers.

 @Configuration//This annotation shows that the class is a spring configuration, equivalent to an xml file. //Configure the scan package. @ComponentScan(basePackages = "cn.my.springboot.javaconfig")public class SpringConfig { @Bean//This annotation is a Bean object, which is equivalent to <bean> public UserDao getUserDao() { return new UserDao();//Directly demonstrate the new object. }}

5. Write a test method to start Spring container.

 public class Test { public static void main(String[] args) { //Instantiate the Spring container through Java configuration. AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(SpringConfig.class); //Get the bean object in the Spring container UserService userService = context.getBean(UserService.class); //Calling the method in the object List<User> list = userService.queryUserList(); for(User user: list) { System.out.println(user.getUsername() + "|" user.getPassword() + "|" user.getAge()); //Destroy the container context.destroy; } }}

Test results:

A perfect alternative to XML configuration files can be used with java code.

As for the structure, please be unclear, it means that people have different opinions.

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