java SpringBoot注解,对象自动注入 java SpringBoot自定义注解,及自定义解析器实现对象自动注入操作

import com.ruoyi.framework.interceptor.annotation.LoginUser;
import com.ruoyi.project.WebMoudle.WebUser.domain.WebUser;
import com.ruoyi.project.WebMoudle.WebUser.service.IWebUserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.MethodParameter;
import org.springframework.stereotype.Service;
import org.springframework.web.bind.support.WebDataBinderFactory;
import org.springframework.web.context.request.NativeWebRequest;
import org.springframework.web.context.request.RequestAttributes;
import org.springframework.web.method.support.HandlerMethodArgumentResolver;
import org.springframework.web.method.support.ModelAndViewContainer;

/**
 * 有@LoginUser注解的controller方法会进入到解析器中
 * 通过解析器查询到当前用户，并返回给controller *
 * @author yangz
 */
@Service
public class LoginUserHandlerMethodArgumentResolver implements HandlerMethodArgumentResolver {

 //用户service
  @Autowired
  private IWebUserService webUserService;

  @Override
  public boolean supportsParameter(MethodParameter parameter) {
    return parameter.getParameterType().isAssignableFrom(WebUser.class) && parameter.hasParameterAnnotation(LoginUser.class);
  }

  @Override
  public Object resolveArgument(MethodParameter parameter, ModelAndViewContainer container,
                 NativeWebRequest request, WebDataBinderFactory factory) throws Exception {
    //从request作用域中获取登录时存入的用户ID，不明白的可以查看我的博客springBoot拦截器一文
    Object object = request.getAttribute(AuthorizationInterceptor.LOGIN_USER_KEY, RequestAttributes.SCOPE_REQUEST);
    if (object == null) {
      return null;
    }

    //获取用户信息
    Long userId=(Long) object;
    WebUser user = webUserService.selectWebUserById(userId);
    return user;
  }
}

import com.ruoyi.framework.interceptor.LoginUserHandlerMethodArgumentResolver;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.method.support.HandlerMethodArgumentResolver;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import java.util.List;

@Configuration
public class LoginUserConfig extends WebMvcConfigurerAdapter {


    /**
   * 此处获取拦截器实例化对象，同理拦截器
   * @return
   */
  @Bean
  public LoginUserHandlerMethodArgumentResolver getLoginUserHandlerMethodArgumentResolver(){
    return new LoginUserHandlerMethodArgumentResolver();
  }

  @Override
  public void addArgumentResolvers(List<HandlerMethodArgumentResolver> argumentResolvers){
    super.addArgumentResolvers(argumentResolvers);
    argumentResolvers.add(getLoginUserHandlerMethodArgumentResolver());
  }
}

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * 注入用户信息注解，
 *比较简单，没有声明更多的属性
 * @author lipengjun
 * @email 939961241@qq.com
 * @date 2017-03-23 20:39
 */
@Target(ElementType.PARAMETER)
@Retention(RetentionPolicy.RUNTIME)
public @interface LoginUser {

}

  @RequestMapping(value = "/prepay")
  @ResponseBody
  public Map<String,Object> prepay(@LoginUser WebUser webUser){
   //此间，从request中获取到userId信息就会在进入controller之前将webuser对象查出并注入到webUser参数中
  }

@Data //lombok注解
public class User {
  private Integer userId;
  private String userName;
}

public class UserConfig {
  @Bean
  public User getUser(){
    User user = new User();
    user.setUserId(1);
    user.setUserName("你好啊 哈哈哈哈");
    return user;
  }
}

@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
@AutoConfigurationPackage
@Import(UserConfig.class)
public @interface EnableAutoImport {
}

@SpringBootApplication
@EnableAutoImport  //打上你自定义的注解
public class DemoApplication implements InitializingBean {
//这里实现了InitializingBean 在初始化bean的时候都会执行afterPropertiesSet
  @Autowired
  private User user;  //注入 user类

  public static void main(String[] args) {

    SpringApplication.run(DemoApplication.class, args);
  }

  @Override
  public void afterPropertiesSet() throws Exception {
   //在这里调用了装配进来的类
    System.out.println(user.getUserName());
  }
}