学习了一周的springMVC
今天搭建一个SpringMVC的登录案例
主要是用来巩固一下拦截器的是使用。

1.首先配置web.xml 配置
主要是配置encodingfilter和dispatcher

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
         version="3.1">
    <!--字符集设置-->
    <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>
    </filter>
    <filter-mapping>
        <filter-name>encodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>


    <!--调度器配置-->
    <servlet>
        <servlet-name>dispatcher</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>dispatcher</servlet-name>
        <url-pattern>*.form</url-pattern>
    </servlet-mapping>
</web-app>

2.配置dispatcher指定的servlet.xml
主要配置拦截器的相关属性

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="
        http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context.xsd">
    <!--指定注解解析的包-->
    <context:component-scan base-package="com.jsu.controller"/>
    <!--配置拦截器-->
    <mvc:interceptors>
        <mvc:interceptor>
            <mvc:mapping path="/**"/>
           <!-- 指定拦截器的bean -->
            <bean class="com.jsu.intercepter.LoginIntercepter">

                <property name="allowAdress">
                    <!--允许通过的请求的列表-->
                    <list>
                        <value>login.form</value>
                        <value>add.form</value>
                    </list>
                </property>
            </bean>
        </mvc:interceptor>
    </mvc:interceptors>


</beans>

前车之鉴：千万不能使用如下配置不然会无法识别拦截器的拦截名单

<property name="allowAdress">
                    <!--允许通过的请求的列表-->
                    <list>
                        <value>
                            login.form
                        </value>
                        <value>
                            add.form
                        </value>
                    </list>
                </property>

3.配置intercepter的类
主要通过实现handlerintercepter接口

public class LoginIntercepter implements HandlerInterceptor {
    //拦截名单
    List<String> allowAdress;

    public void setAllowAdress(List<String> allowAdress) {
        this.allowAdress = allowAdress;
    }

    /**
     * 请求方法执行前所执行的方法
     * 返回true 则进行拦截
     * 否则不进行拦截
     */
    @Override
    public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o) throws Exception {
        //获取请求的路径
        String url = httpServletRequest.getRequestURL().toString();
        //查看是否已经有请求
        Object user = httpServletRequest.getSession().getAttribute("user");

        if (user != null){
            return true;
        }
        for (String temp : allowAdress) {
            if (url.endsWith(temp)) {
                return true;
            }
        }
        //重定向到login页面
        httpServletResponse.sendRedirect(httpServletRequest.getContextPath()+"/login.jsp");
        return false;
    }

    @Override
    public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {

    }

    @Override
    public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {

    }
}

4.配置controller类

@Controller
public class LoginController {
    @RequestMapping("/login")
    public String login(User user,HttpSession session){
        //校验
        if ("zzz".equals(user.getName())&&"123".equals(user.getPassword())) {

            session.setAttribute("user", user);
            return "redirect:index.jsp";
        }
        return "redirect:login.jsp";
    }

    @RequestMapping("/add")
    public String add(){
        System.out.println("add");
        return "redirect:index.jsp";
    }
}

5.配置实体类

public class User{

    private String name;
    private String password;



    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }
}

6.demo结果

错误结果就重定向到login.jsp页面