SpringMVC基础-14-拦截器使用案例-权限控制

pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.monkey1024</groupId>
  <artifactId>03mvc</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>war</packaging>
  <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>3.8.1</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.1.0</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.0.4.RELEASE</version>
        </dependency>
 
    </dependencies>
    <build>
    	<!-- 与工程名一致 -->
        <finalName>03mvc</finalName>
        <plugins>
            <!-- 编译插件，指定编译用的的jdk版本 -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <!-- jdk的版本号 -->
                    <source>1.8</source>
                    <target>1.8</target>
                    <encoding>UTF-8</encoding>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
  <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:springmvc.xml</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>springMVC</servlet-name>
    <url-pattern>*.do</url-pattern>
  </servlet-mapping>
</web-app>

springmvc.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">
 	
 	<!-- 注解驱动 -->
 	<mvc:annotation-driven/>
 	
 	<!-- 注册组件扫描器 -->
 	<context:component-scan base-package="com.monkey1024.*"/>
 	
 	<!-- 注册拦截器 -->
 	<mvc:interceptors>
 		<mvc:interceptor>
 			<mvc:mapping path="/**"/>
 			<bean class="com.monkey1024.interceptor.MyInterceptor"/>
 		</mvc:interceptor>
 		<mvc:interceptor>
 			<mvc:mapping path="/**"/>
 			<bean class="com.monkey1024.interceptor.MyInterceptor2"/>
 		</mvc:interceptor>
 		<mvc:interceptor>
 			<mvc:mapping path="/**"/>
 			<bean class="com.monkey1024.interceptor.PermissionInterceptor"/>
 		</mvc:interceptor>
 	</mvc:interceptors>
	
	<!-- 内部视图解析器 -->
	<bean
		class="org.springframework.web.servlet.view.InternalResourceViewResolver">
		<property name="prefix" value="/jsp/" />
		<property name="suffix" value=".jsp" />
	</bean>
	
	
 
</beans> 

PermissionInterceptor.java

package com.monkey1024.interceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

/*
 * 权限拦截器
 */
public class PermissionInterceptor implements HandlerInterceptor {
	public  boolean preHandle(HttpServletRequest request,HttpServletResponse response,Object handler) throws Exception{
		System.out.println("拦截器中的preHandle方法");
		String user = (String) request.getSession().getAttribute("user");
		//判断用户名为monkey1024的用户是否已登录
		if(!"monkey1024".equals(user)){
			request.getRequestDispatcher("/jsp/fail.jsp").forward(request, response);
			//不进行后续处理
			return false;
		}
		return true;
	}
	public void postHandle(HttpServletRequest request,HttpServletResponse response,Object handler,ModelAndView modelAndView) throws Exception{
		System.out.println("拦截器中的postHandle方法");
		
	}
	public void afterCompletion(HttpServletRequest request,HttpServletResponse response,Object handler,Exception ex) throws Exception{
		System.out.println("拦截器中的afterCompletion方法");
		
	}
}

LoginController.java

package com.monkey1024.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;

/*
 * 登陆
 */
@Controller
public class LoginController {
	@RequestMapping("/welcome.do")
	public ModelAndView welcome() throws Exception{
		ModelAndView mv = new ModelAndView();
		mv.addObject("welcome","欢迎登陆本系统");
		mv.setViewName("/welcome");
		return mv;
	}
}

fail.jsp

<%@ page language="java" contentType="text/html; charset=utf-8"
    pageEncoding="utf-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
登录失败
</body>
</html>

welcome.jsp

<%@ page language="java" contentType="text/html; charset=utf-8"
    pageEncoding="utf-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
${welcome }

</body>
</html>

login.jsp

<%@ page language="java" contentType="text/html; charset=utf-8"
    pageEncoding="utf-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
	<!-- 当访问该页面的时候，表示已经登录 -->
	<%
		request.getSession().setAttribute("user","monkey1024");
	%>
</body>
</html>