登陆拦截案例

登陆拦截器小案例，判断登陆的用户名及密码是否正确；：

1.创建一个maven项目，导入相关的坐标：

    org.springframeworkspring-webmvc5.2.12.RELEASEjavax.servletjavax.servlet-api4.0.1providedjavax.servlet.jspjsp-api2.2provided

org.apache.tomcat.maventomcat7-maven-plugin2.2

将打包方式设置为war:

    war

2.设置打包方式之后打开项目的模块设置，添加webapp和WEB-INF

得出项目结构：

3.在resources文件中添加配置文件spring-mvc.xml

4.在web.xml中加载spring-mvc.xml

springmvcorg.springframework.web.servlet.DispatcherServletcontextConfigLocationclasspath:spring-mvc.xmlspringmvc/filterorg.springframework.web.filter.CharacterEncodingFilterencodingUTF-8forceEncodingtruefilter/*

5.添加页面index.jsp文件：

<%@ page contentType="text/html;charset=UTF-8" language="java" %>




用户名：
密码：

6.在main/java包下创建com包，在com包下创建controller包在controller包下创建loginController类

@Controller
@RequestMapping("/com")
public class loginController {@RequestMapping("/login")@ResponseBodypublic String login(String passWorld,String userName) {System.out.println(passWorld);System.out.println(userName);return "登陆成功";}
}

7.在spring-mvc.xml文件下配置注解扫描，和开启注解扫描

 text/html;charset=UTF-8application/json;charset=UTF-8text/plain;charset=UTF-8application/xml;charset=UTF-8

8.在com/interceptor包下创建拦截器，

自定义拦截器有两种：

1. 实现HandlerInterceptor接口
2. 继承HandlerInterceptorAdapter类

这里我两种都用了：一种用来验证用户名，一种用来验证用户密码；

实现HandlerInterceptor接口：

public class MyIterceptor implements HandlerInterceptor {@Overridepublic boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {if ("123".equals(request.getParameter("passWorld"))){System.out.println("密码验证正确，放行2");return true;}return false;}@Overridepublic void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {System.out.println("方法执行后2");}@Overridepublic void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {System.out.println("页面渲染后2");}
}

继承HandlerInterceptorAdapter类：

public class MyIterceptor2 extends HandlerInterceptorAdapter {@Overridepublic boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {if ("张三".equals(request.getParameter("userName"))){request.setAttribute("messege","登陆成功");System.out.println("姓名验证成功放行1");return true;}return false;}@Overridepublic void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {System.out.println("方法执行后1");}@Overridepublic void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {System.out.println("页面渲染后1");}
}

9.创建完拦截器之后再spring-mvc.xml文件中配置拦截配置

10:查看效果：

提交前：

提交后控制台输出：

提交后页面：

上面是成功的下面我来测试一组失败的数据：

控制台输出：

页面放回的为空白；