vip21-springMvc/day04/src/main/java/com/lovecoding/mvc/config/MyInterceptor.java

package com.lovecoding.mvc.config;

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

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

public class MyInterceptor implements HandlerInterceptor {

    /**
     * preHandle 是我们调用 控制器 函数之前 被执行
     * @param request
     * @param response
     * @param handler
     * @return
     * @throws Exception
     */
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
            throws Exception {
        System.out.println( "=========》preHandle 被调用" );
        return true;
    }

    /**
     * postHandle 是在 控制器执行完毕， 页面渲染之前 被执行
     * @param request
     * @param response
     * @param handler
     * @param modelAndView
     * @throws Exception
     */
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
                            @Nullable ModelAndView modelAndView) throws Exception {

        System.out.println( "=========》postHandle 被调用" );
    }

    /**
     * afterCompletion 是视图渲染完成被执行
     * @param request
     * @param response
     * @param handler
     * @param ex
     * @throws Exception
     */
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler,
                                 @Nullable Exception ex) throws Exception {
        System.out.println( "=========》afterCompletion 被调用" );
    }

}