Springboot interceptor HandlerInterceptor injection problem

1. Problem description

   After the project is started, the injection under the interceptor is null, which affects the logical operation of the interceptor. As shown below:

Second, the solution strategy

   Reason:  Interceptor loading is completed before springcontext is created. For details, please refer to the relationship between spring's interceptor loading process and IOC

  Solution 1 : Use @Bean to load the class before the interceptor is initialized. The focus is on @Bean's interceptor processing and the introduction of getCheckFilter()

 details as follows:

// 拦截器处理
public class CheckFilter implements HandlerInterceptor {

    @Autowired
    private SystemService systemService;
}


// 配置类处理

@Configuration
public class WebMvcConfig extends WebMvcConfigurationSupport {

    @Bean
    public CheckFilter getCheckFilter(){
        return  new CheckFilter();
    }

    @Override
    protected void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(getCheckFilter()).addPathPatterns("/**").
                excludePathPatterns("/admin/auth/**");
        super.addInterceptors(registry);
    }

    @Override
    protected void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/static/**").addResourceLocations("classpath:/static/");
        super.addResourceHandlers(registry);
    }

    @Override
    protected void configureViewResolvers(ViewResolverRegistry registry) {
        registry.jsp("/WEB-INF/",".jsp");
        super.configureViewResolvers(registry);
    }
}

Solution 2 : Add configuration annotations such as @Configuration, @Component  to the interceptor . Inject in the configuration class , the specific operations are as follows:

// 拦截器处理
@Configuration   //或者 @Component
public class CheckFilter implements HandlerInterceptor {

    @Autowired
    private SystemService systemService;
}


// 配置类处理

@Configuration
public class WebMvcConfig extends WebMvcConfigurationSupport {

    @Autowired
    private CheckFilter  checkFilter;

    @Override
    protected void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(checkFilter).addPathPatterns("/**").
                excludePathPatterns("/admin/auth/**");
        super.addInterceptors(registry);
    }

    @Override
    protected void addResourceHandlers(ResourceHandlerRegistry registry) {
 registry.addResourceHandler("/static/**").addResourceLocations("classpath:/static/");
        super.addResourceHandlers(registry);
    }

    @Override
    protected void configureViewResolvers(ViewResolverRegistry registry) {
        registry.jsp("/WEB-INF/",".jsp");
        super.configureViewResolvers(registry);
    }
}

Three, knowledge summary

  1. Involving spring's interceptor loading process and IOC management

  2. Reference materials https://blog.csdn.net/dengdeng333/article/details/87878882