springmvc登陆拦截案例

一、web.xml

<?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" 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>z-springmvc-loginIntercept</display-name>
  <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:mvc.xml</param-value>
      </init-param>
      <load-on-startup></load-on-startup>
  </servlet>
  <servlet-mapping>
      <servlet-name>springmvc</servlet-name>
      <url-pattern>*.do</url-pattern>
  </servlet-mapping>
  <servlet-mapping>
      <servlet-name>springmvc</servlet-name>
      <url-pattern>*.action</url-pattern>
  </servlet-mapping>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
</we

二、mvc.xml

<?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:p="http://www.springframework.org/schema/p"
    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">
     <!-- 配置渲染器 -->
    <bean id="jspViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
      <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/>
      <!-- 结果视图的前缀-->
      <property name="prefix" value="/WEB-INF/jsp/"/>
      <!-- 结果视图的后缀-->
      <property name="suffix" value=".jsp"/>
    </bean>
    <!-- 自动扫描com.springmvc.controller包下的controller-->
    <context:component-scan base-package="com.springmvc.controller"></context:component-scan>
    <!-- 拦截器配置-->
    <mvc:interceptors>
        <mvc:interceptor>
            <mvc:mapping path="/**"/><!-- 拦截所有-->
            <bean class="com.springmvc.intercept.LoginIntercept">
                <property name="allowedPass">
                    <list>
                        <value>login.do</value><!--不拦截login.do-->
                    </list>
                </property>
            </bean>
        </mvc:interceptor>
    </mvc:interceptors>
</beans>

三、controller

@Controller
public class LoginController {
    //登陆
    @RequestMapping("/login")
    public ModelAndView view(User user,HttpSession session){
        ModelAndView view = new ModelAndView();
        //判断user是否为空 以及 用户名和密码是否正确
        if(user.getUsername()!=null && user.getPassword()!=null && user.getUsername().equals("jjz") && user.getPassword().equals("123456")){
            session.setAttribute("user", user);//如果正确，将user保存在session中
            view.setViewName("index");//跳转到index
        }else{
            view.setViewName("login");//否则还是在登陆页面
        }

        return view;
    }
    //add
    @RequestMapping("/add")
    public ModelAndView add(){
        System.out.println("add");//在控制台打印add
        ModelAndView view = new ModelAndView();
        view.setViewName("index");//跳转到index页面
        return view;

    }
}

四、intercept、

public class LoginIntercept implements HandlerInterceptor{
    private List<String> allowedPass;//允许通过的url集合
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response,
            Object obj) throws Exception {
        Object user = request.getSession().getAttribute("user");//获取session中的user
        if(user!=null)//如果user不为空，直接返回true
            return true;
        String url = request.getRequestURL().toString();//获取url
        for (String temp : allowedPass) {//循环允许通过的url集合，检验当前的url是否在允许通过的url集合中
            if(url.endsWith(temp)){//如果是，直接返回true
                return true;
            }
        }
        response.sendRedirect(request.getContextPath()+"/jsp/login.jsp");//否则直接重定向的login.jsp(此处错误，不能直接访问web-inf下的页面)
        return false;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response,
            Object obj, ModelAndView view) throws Exception {

    }

    @Override
    public void afterCompletion(HttpServletRequest request,
            HttpServletResponse response, Object obj, Exception exception)
            throws Exception {

    }
    //setAllowedPass
    public void setAllowedPass(List<String> allowedPass) {
        this.allowedPass = allowedPass;
    }
}