preHandle:?預(yù)先處理,在目標(biāo)的controller方法執(zhí)行之前,進(jìn)行處理

postHandle:?在目標(biāo)的controller方法執(zhí)行之后,到達(dá)指定頁(yè)面之前進(jìn)行處理

afterCompletion:?在頁(yè)面渲染之后進(jìn)行處理

方法:

1.Springboot通過(guò)實(shí)現(xiàn)HandlerInterceptor接口實(shí)現(xiàn)攔截器

2.通過(guò)WebMvcConfigurer實(shí)現(xiàn)一個(gè)配置類(lèi),再通過(guò)@Configuration 注解注入到容器

3.指定攔截規(guī)則

?以用戶登錄為案例,若用戶沒(méi)有登錄session里面就沒(méi)有用戶的數(shù)據(jù),就會(huì)轉(zhuǎn)到首頁(yè)登錄頁(yè)面

在正確登錄之后，就將reglister保存到session中，再次訪問(wèn)頁(yè)面的時(shí)候，登錄攔截器就可以找到這個(gè)reglister對(duì)象，就不需要再次攔截到登錄界面了.

package com.zwz.springbootweb.interceptor;import org.springframework.context.annotation.Bean; import org.springframework.stereotype.Component; import org.springframework.stereotype.Service; import org.springframework.web.servlet.HandlerInterceptor; import org.springframework.web.servlet.ModelAndView;import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import javax.websocket.Session;public class LoginInterceptor implements HandlerInterceptor {@Overridepublic boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {HttpSession session = request.getSession();Object reglister = session.getAttribute("Reglister");if (reglister != null) {return true;} else {request.setAttribute("msg", "請(qǐng)先登錄!");request.getRequestDispatcher("/").forward(request,response);return false;}}@Overridepublic void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {HandlerInterceptor.super.postHandle(request, response, handler, modelAndView);}@Overridepublic void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {HandlerInterceptor.super.afterCompletion(request, response, handler, ex);} }

?

?之后通過(guò)實(shí)現(xiàn)WebMvcConfigurer接口實(shí)現(xiàn)一個(gè)配置類(lèi)，在配置類(lèi)中注入攔截器，最后再通過(guò) @Configuration 注解注入配置.并且指定攔截的路徑和需要放行的路徑.

注意:攔截器? /**? ?會(huì)攔截一切資源,包括靜態(tài)資源,需要將靜態(tài)資源放行

?

package com.zwz.springbootweb.config;import com.zwz.springbootweb.interceptor.LoginInterceptor; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.web.filter.HiddenHttpMethodFilter; import org.springframework.web.servlet.config.annotation.InterceptorRegistry; import org.springframework.web.servlet.config.annotation.PathMatchConfigurer; import org.springframework.web.servlet.config.annotation.WebMvcConfigurer; import org.springframework.web.util.UrlPathHelper;@Configuration public class WebConfig implements WebMvcConfigurer{@Overridepublic void addInterceptors(InterceptorRegistry registry) {registry.addInterceptor(new LoginInterceptor()).addPathPatterns("/**").excludePathPatterns("/loginjudge","/","/retolo","/static/**");}}

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