SpringMVC组件——拦截器入门

简单的入门案例

一、导入坐标（pom.xml）

 <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
    <!--版本锁定-->
    <spring.version>5.0.2.RELEASE</spring.version>
  </properties>

  <dependencies>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-web</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>servlet-api</artifactId>
      <version>2.5</version>
      <scope>provided</scope>
    </dependency>

    <dependency>
      <groupId>javax.servlet.jsp</groupId>
      <artifactId>jsp-api</artifactId>
      <version>2.0</version>
      <scope>provided</scope>
    </dependency>
  </dependencies>

二、配置前端处理器（web.xml）

<!DOCTYPE web-app PUBLIC
 "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
 "http://java.sun.com/dtd/web-app_2_3.dtd" >

<web-app>
  <display-name>Archetype Created Web Application</display-name>
  <filter>
    <filter-name>characterEncodingFilter</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>characterEncodingFilter</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>

  <servlet>
    <servlet-name>dispatcherServlet</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>dispatcherServlet</servlet-name>
    <url-pattern>/</url-pattern>
  </servlet-mapping>
</web-app>

三、配置一个简单的方法（ViewController）

package edu.xiao;

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

@Controller
@RequestMapping("/view")
public class ViewController {

    @RequestMapping("/testInterceptor")
    public  String testInterceptor(){
        System.out.println("方法...执行");
        return "success";
    }
}

三、配置拦截方法类（TestIntercep）

package edu.xiao.intercep;

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

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

public class TestIntercep implements HandlerInterceptor {
    /**
     * 在所有的Controller和jsp之前
     * @param request
     * @param response
     * @param handler
     * @return 返回true放行，反之拦截
     * @throws Exception
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("preHandle。。。");
        return true;
    }

    /**
     * 在Controller之后，jsp之前
     * @param request
     * @param response
     * @param handler
     * @param modelAndView
     * @throws Exception
     */
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("postHandle。。。");

    }

    /**
     * 在所有的Controller和jsp之后
     * @param request
     * @param response
     * @param handler
     * @param ex
     * @throws Exception
     */
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("afterCompletion。。。");

    }
}

四、写配置文件（springmvc.xml）

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xmlns:context="http://www.springframework.org/schema/context"
       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">
    <!--配置扫描包-->
    <context:component-scan base-package="edu.xiao"/>
    <!--视图解析器-->
    <bean id="internalResourceViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <!--文件所在目录-->
        <property name="prefix" value="/WEB-INF/pages/" />
        <!--文件的后缀名-->
        <property name="suffix" value=".jsp"/>
    </bean>
    <!--配置拦截器,可以配置多个-->
    <mvc:interceptors>
        <!--配置第一个拦截器-->
        <mvc:interceptor>
            <!--拦截controller中具体哪个方法,除了这个，其他的不拦截-->
            <mvc:mapping path="/view/*"/>
            <!--不拦截controller中具体哪个方法,除了这个，其他的拦截
            <mvc:exclude-mapping path=""/>-->
            <!--配置拦截器对象bean-->
            <bean class="edu.xiao.intercep.TestIntercep"/>
        </mvc:interceptor>
    </mvc:interceptors>

    <mvc:annotation-driven  />
</beans>

五、配置jsp页面

1、index.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" isELIgnored="false" %>
<html>
<body>
<h2>Hello World!</h2>
<a href="view/testInterceptor">testInterceptor</a>
</body>
</html>

2、success.jsp

<%--
  Created by IntelliJ IDEA.
  User: dell
  Date: 2020/4/4
  Time: 18:59
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" isELIgnored="false" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<h3>success</h3>
<%
    System.out.println("页面执行。。。"); %>
</body>
</html>

控制台效果