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Editor to share with you how to use the interceptor in java SpringMvc, I believe most people do not know much about it, so share this article for your reference, I hope you can learn a lot after reading this article, let's go to know it!

What is an interceptor?

The Interceptor is a component in SpringMVC.

You can make the code in the interceptor execute when many requests are processed.

The interceptor can choose to block execution or release.

Take a chestnut:

Basic use

Implement the HandlerInteceptor interceptor interface in SpringMVC, and this class is an interceptor class.

Using the return value of the interceptor's core active control preHandle method, the return of true is successful, and the return of false indicates that the interception is processed.

Example

First, create a class inheritance interceptor

Public class DemoInterceptor implements HandlerInterceptor {@ Override public boolean preHandle (HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {System.out.println ("prehandle"); return true;} / / execute @ Override public void postHandle (HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {System.out.println ("posthandle") after the controller } / / execute @ Override public void afterCompletion (HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {System.out.println ("afterComplete") after view processing;}}

Return to true to continue execution

ReFactor the SpringMvcConfig class to work

@ Configuration@ComponentScan ("cn.tedu.controller") / / WebMvcConfigurer is the configuration template of springmvc. Use @ EnableWebMvcpublic class SpringMvcConfig implements WebMvcConfigurer {/ / rewrite the interceptor method in the configuration template @ Override public void addInterceptors (InterceptorRegistry registry) {/ / create the DemoInterceptor object, register with the SpringMVC / / addPathPatterns () method to specify the interceptor to URL / / register an interceptor Execute interceptor to function registry.addInterceptor (new DemoInterceptor ()) .addPathPatterns ("/ home/index.do") when requesting / home/index.do }}

Implementing the interceptor method in WebMvcConfigurer rewriting configuration template

WebMvcConfigurer is a configuration template for springmvc and is used with @ EnableWebMvc annotations

Create a DemoInterceptor object and register it in SpringMVC.

The addPathPatterns () method acts as a convention interceptor to URL

Execute View interceptor execute sequentially

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