What is the configuration method of java in springboot

1. Create User entity class.

@Data
public 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>();
  //模拟数据库查询
  for(int i = 1;i <p><strong>3. Write UserService to implement User data operation business logic. </strong></p>
<pre class="brush:php;toolbar:false">@service
public class UserService{
 @Autowired//注入Spring容器中的bean对象
 private UserDao userDao;
 public List<user> queryUserList() {
  //调用userDao中的方法进行查询。
  return this.userDao.queryUserList();
 }
}</user>

4. Write SpringConfig to instantiate the Spring container.

@Configuration//通过该注解来表明该类是一个spring的配置，相当于一个xml文件。
//配置扫描包。
@ComponentScan(basePackages = "cn.my.springboot.javaconfig")
public class SpringConfig {
 @Bean//通过该注解来表明是一个Bean对象，相当于xml中的<bean>
 public UserDao getUserDao() {
  return new UserDao();//直接new对象作演示。
 }
}</bean>

5. Write a test method to start the Spring container.

public class Test {
 public static void main(String[] args) {
  //通过java配置来实例化Spring容器。
  AnnotationConfigApplicationContext context = new
  AnnotationConfigApplicationContext(SpringConfig.class);

  //在Spring容器中获取bean对象
  UserService userService = context.getBean(UserService.class);

  //调用对象中的方法
  List<user> list = userService.queryUserList();
  for(User user : list) {
   System.out.println(user.getUsername() + "|" user.getPassword() + "|" user.getAge());
  //销毁该容器
  context.destroy;
  }
 }
}</user>

Test results:

You can use java code to perfectly replace the XML configuration file.

As for the structure, please don’t be clear, it’s all in the eye of the beholder.

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