The Spring MVC Interceptor (Handlerinterceptor) uses

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Today, Spring MVC's processor interceptors (Handlerinterceptor) are similar to filter filters in the servlet specification for preprocessing and post-processing of processors. Handlerinterceptor Interface

The Handlerinterceptor interface is defined as follows:

Package org.springframework.web.servlet;

Import Javax.servlet.http.HttpServletRequest;
Import Javax.servlet.http.HttpServletResponse;
Import Org.springframework.web.method.HandlerMethod;

Public interface Handlerinterceptor {

    /**
     * Preprocessing callback method
     * True indicates continuation process, FALSE indicates process interrupt */
    Boolean Prehandle (HttpServletRequest request, httpservletresponse response, Object handler)
            throws Exception;

    /**
     * post-processing callback method to implement post-processing of the processor (but before rendering the view), at which time the model data can be processed by modelandview or treated on the views
     */
    void Posthandle (
            HttpServletRequest request, HttpServletResponse response, Object handler, Modelandview Modelandview)
            throws Exception;

    /**
     * The entire request is processed by the callback method, that is, callback
    /void Aftercompletion (HttpServletRequest request) When the view is rendered
            . HttpServletResponse response, Object handler, Exception ex)
            throws Exception;

}

Spring MVC provides a Handlerinterceptoradapter adapter class that allows us to selectively implement the methods of interest, as follows:

Package Org.springframework.web.servlet.handler;
Import Javax.servlet.http.HttpServletRequest;

Import Javax.servlet.http.HttpServletResponse;
Import Org.springframework.web.servlet.AsyncHandlerInterceptor;

Import Org.springframework.web.servlet.ModelAndView; /** * Abstract Adapter class for the {@link Asynchandlerinterceptor} interface, * for simplified implementation of Pre-o
 Nly/post-only interceptors. * * @author Juergen Hoeller * @since 05.12.2003 * * Public abstract class Handlerinterceptoradapter implements Asynchand
     Lerinterceptor {/** * This implementation always returns {@code true}.
            */@Override public boolean prehandle (HttpServletRequest request, httpservletresponse response, Object handler)
    Throws Exception {return true;
     }/** * This implementation is empty. */@Override public void Posthandle (HttpServletRequest request, httpservletresponse response, Object Handler, Modelandview modeLandview) throws Exception {}/** * This implementation is empty. */@Override public void aftercompletion (HttpServletRequest request, httpservletresponse response, Ob
     Ject handler, Exception ex) throws Exception {}/** * This implementation is empty. */@Override public void afterconcurrenthandlingstarted (HttpServletRequest request, Httpservletrespon SE response, Object handler) throws Exception {}}

The

is similar to Channelinboundhandler and Channelinboundhandleradapter in Netty4.1. Use

<?xml version= "1.0" encoding= "UTF-8"?> <beans xmlns= "Http://www.springframework.org/schema/beans" Xmlns:xs
       I= "Http://www.w3.org/2001/XMLSchema-instance" xmlns:context= "Http://www.springframework.org/schema/context" Xmlns:mvc= "Http://www.springframework.org/schema/mvc" xsi:schemalocation= "Http://www.springframework.org/schema /beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/ Context Http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/ MVC http://www.springframework.org/schema/mvc/spring-mvc.xsd "> <mvc:annotation-driven/> <context:com Ponent-scan base-package= "Com.bytebeats.springmvc.ch5.controller" > <context:include-filter type= "annotation "expression=" Org.springframework.stereotype.Controller "/> </context:component-scan> <mvc:intercepto
      Rs> <mvc:interceptor>      <mvc:mapping path= "/**"/> <bean class= "Com.bytebeats.springmvc.ch5.controller.interceptor.LogI Nterceptor "/> </mvc:interceptor> <mvc:interceptor> <mvc:mapping path="/api/ * * "/> <mvc:exclude-mapping path="/api/auth/login "/> <mvc:exclude-mapping path="/api/ 
        Auth/register "/> <bean class=" Com.bytebeats.springmvc.ch5.controller.interceptor.AuthInterceptor "/> </mvc:interceptor> </mvc:interceptors> </beans>

Loginterceptor

Import Java.util.Set;
Import Javax.servlet.http.HttpServletRequest;
Import Javax.servlet.http.HttpServletResponse;
Import Org.slf4j.Logger;
Import Org.slf4j.LoggerFactory;
Import org.springframework.beans.factory.annotation.Autowired;
Import Org.springframework.web.servlet.HandlerInterceptor;


Import Org.springframework.web.servlet.ModelAndView; public class Loginterceptor implements handlerinterceptor{private Logger Logger = Loggerfactory.getlogger (loginterce

    Ptor.class); @Override public boolean prehandle (HttpServletRequest request, httpservletresponse response, Object handle
        R) throws Exception {if (condition) {return false;
    } return true; } @Override public void Posthandle (HttpServletRequest request, httpservletresponse response, Object H Andler, Modelandview Modelandview) throws Exception {} @Override public void Aftercompletion (Ht
            Tpservletrequest request,HttpServletResponse response, Object handler, Exception ex) throws Exception {}} 

Application ScenariosLog records: Log the request information for information monitoring, information statistics, calculation pv,trace tracking, and so on. Permission check: such as login detection, enter the processor detection check whether to log in, if not directly back to the login page; performance monitoring: Sometimes the system in a certain period of time inexplicably slow, can pass through the interceptor before entering the processor before the start time, in processing the PostScript;

The internal implementation principle of Handlerinterceptor is described in detail in the next article.