一、實驗介紹
1.1 實驗內容
本節課程主要利用 Spring MVC 框架實現攔截器以及 Spring MVC 框架的整合。
1.2 實驗知識點
- Spring MVC 框架
- 攔截器
1.3 實驗環境
- JDK1.8
- Eclipse JavaEE
二、實驗步驟
2.1 攔截器實現
在項目 hrms 的目錄 src/main/java 下新建包 com.shiyanlou.interceptor，并在該包下新建類 LoginInterceptor，來驗證用戶是否登錄，代碼如下：
package com.shiyanlou.interceptor;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView; public class LoginInterceptor implements HandlerInterceptor { // 不攔截 "/login" 請求 private static final String[] IGNORE_URI = { "/login" }; @Override public void afterCompletion(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, Exception arg3) throws Exception { } @Override public void postHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, ModelAndView arg3) throws Exception { } // 該方法將在 Controller 處理前進行調用 @Override public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { // flag 表示是否登錄 boolean flag = false; // 獲取請求的 URL String url = request.getServletPath(); for (String s : IGNORE_URI) { if (url.contains(s)) { flag = true; break; } } if (!flag) { // 獲取 Session 并判斷是否登錄 String username = (String) request.getSession().getAttribute( "username"); if (username == null) { request.setAttribute("message", "Please log in first!"); // 如果未登錄，進行攔截，跳轉到登錄頁面 request.getRequestDispatcher("/login.jsp") .forward(request, response); } else { flag = true; } } return flag; } } 2.2 spring-mvc.xml 配置文件
在目錄 src/main/resources 下新建 Spring MVC 配置文件 spring-mvc.xml，添加如下代碼：
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="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-4.2.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.2.xsd"> <!-- 自動掃描該包，Spring MVC 會將包下用 @Controller 注解的類注冊為 Spring 的 controller --> <context:component-scan base-package="com.shiyanlou.controller" /> <!-- 設置默認配置方案 --> <mvc:annotation-driven /> <!-- 靜態資源訪問 --> <mvc:resources location="/" mapping="/**" /> <!-- 視圖解析器 --> <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="prefix" value="/" /> <property name="suffix" value=".jsp" /> </bean> <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver"> <property name="maxUploadSize" value="3500000" /> <property name="defaultEncoding" value="UTF-8" /> </bean> <!-- 配置攔截器 --> <mvc:interceptors> <mvc:interceptor> <mvc:mapping path="/*" /> <bean class="com.shiyanlou.interceptor.LoginInterceptor" /> </mvc:interceptor> </mvc:interceptors> </beans> 2.3 配置 web.xml
修改項目 hrms 的 src->main->webapp->WEB-INF 目錄下的 web.xml 內容如下：
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0"> <display-name>hrms</display-name> <!-- 配置 Spring 核心監聽器 --> <listener> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> </listener> <!-- 指定 Spring 的配置文件 --> <context-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:spring-mybatis.xml</param-value> </context-param> <!-- 定義 Spring MVC 前端控制器 --> <servlet> <servlet-name>springMVC</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <init-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:spring-mvc.xml</param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> <!-- 為 DispatcherServlet 建立映射 --> <servlet-mapping> <servlet-name>springMVC</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> <listener> <listener-class>org.springframework.web.util.IntrospectorCleanupListener</listener-class> </listener> <!-- 編碼過濾器 --> <filter> <filter-name>encodingFilter</filter-name> <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class> <init-param> <param-name>encoding</param-name> <param-value>UTF-8</param-value> </init-param> <init-param> <param-name>forceEncoding</param-name> <param-value>true</param-value> </init-param> </filter> <filter-mapping> <filter-name>encodingFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> <!-- 設置首頁 --> <welcome-file-list> <welcome-file>login.jsp</welcome-file> </welcome-file-list> </web-app> 三、實驗總結
到這里我們就實現了攔截器和 Spring MVC 的整合，項目的代碼全部完成，下一節我們將對實現的系統進行運行測試。
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