How to create a Spring Boot interceptor

To create a Spring Boot interceptor, you need to follow these steps:

1. An interceptor for handling requests.
2. Before handling the request
3. manage()
4. onceFinished()

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class CustomInterceptor implements HandlerInterceptor {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        // 在请求处理之前进行调用（Controller方法调用之前）
        return true; // 如果返回false，则请求中断
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        // 请求处理之后进行调用，但是在视图被渲染之前（Controller方法调用之后）
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        // 在整个请求结束之后被调用，也就是在DispatcherServlet渲染了对应的视图之后执行（主要是用于进行资源清理工作）
    }

}

1. Configurable web MVC adapter
2. include interceptors
3. Set up or configuration
4. Activate WebMvc
5. Override the following
6. includeInterceptors()

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

@Configuration
public class WebMvcConfig extends WebMvcConfigurerAdapter {

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new CustomInterceptor()).addPathPatterns("/**");
        // 添加自定义拦截器，并设置拦截路径，这里设置拦截所有请求
    }

}

In this way, you have created a simple Spring Boot interceptor. When a request enters the application, the interceptor’s preHandle() method is called, and then decides whether to interrupt the request based on the return value; after the request is processed, the interceptor’s postHandle() method is called, executed before view rendering; finally, after the entire request is completed, the interceptor’s afterCompletion() method is called for resource cleanup.