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SpringMVC interceptors to configure and use
Ideas:
- Priority loading spring-mvc.xml web.xml configuration when the front end controller initialization SpringMVC
- Use <mvc: interceptors> SpringMVC the xml configuration file in which the tag is added to bean interceptor class
- Write interceptor classes, inheritance extends HandlerInterceptorAdapter class, rewrite preHandle, postHandle method and afterCompletion
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_2_5.xsd" version="2.5">
<display-name>com</display-name>
<welcome-file-list>
<welcome-file>web/index.jsp</welcome-file>
</welcome-file-list>
<!-- 利用web.xml的特性优先过滤静态资源 -->
<servlet-mapping>
<servlet-name>default</servlet-name>
<url-pattern>*.js</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>default</servlet-name>
<url-pattern>*.css</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>default</servlet-name>
<url-pattern>*.html</url-pattern>
</servlet-mapping>
<!-- 加载spring的配置文件 -->
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:spring-core.xml</param-value>
</context-param>
<!-- spring web的监听器 IOC -->
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<!-- 开始配置过滤器 中文字符过滤器-->
<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>
<!-- 配置springmvc的核心servlet -->
<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:spring-mvc.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>spring-core.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:aop="http://www.springframework.org/schema/aop"
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/context
http://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop.xsd ">
<!-- 1. 扫描需要依赖注入的注解bean -->
<context:component-scan base-package="com.gxwz.code" />
<context:component-scan base-package="com.gxwz.core" />
</beans>spring-mvc.xml (key configuration files)
<?xml version="1.0" encoding="UTF-8"?>
<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/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 ">
<!-- web层操作 -->
<!-- 1. 扫描具有HTTP协议的注解bean -->
<context:component-scan base-package="com.gxwz.web" />
<!-- 2. 开启springmvc的注解功能 -->
<mvc:annotation-driven />
<!-- 3. 使用springMVC的拦截器功能 -->
<mvc:interceptors>
<mvc:interceptor>
<mvc:mapping path="/**"/>
<bean class="com.gxwz.interceptor.IndexInterceptor"></bean>
</mvc:interceptor>
</mvc:interceptors>
<!-- 3. 配置静态资源不被springmvc拦截 location：本地资源路径，注意必须是webapp根目录下的路径
<mvc:resources mapping="/css/**" location="/web/static/h-ui/css/" />
<mvc:resources mapping="/images/**" location="/web/static/h-ui/images/" />
<mvc:resources mapping="/js/**" location="/web/static/h-ui/js/" /> -->
</beans>IndexInterceptor.java
package com.gxwz.interceptor;
import java.util.Date;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;
/**
* 在业务处理器处理请求之前被调用
* 如果返回false
* 从当前的拦截器往回执行所有拦截器的afterCompletion(),再退出拦截器链
* 如果返回true
* 执行下一个拦截器,直到所有的拦截器都执行完毕
* 再执行被拦截的Controller
* 然后进入拦截器链,
* 从最后一个拦截器往回执行所有的postHandle()
* 接着再从最后一个拦截器往回执行所有的afterCompletion()
* 与过滤器的区别
* 1.过滤器是依赖于Servlet容器,基于回调函数,Interceptor依赖与框架,基于反射机制
* 2.过滤器的过滤范围更大,还可以过滤一些静态资源,拦截器只拦截请求
*/
public class IndexInterceptor extends HandlerInterceptorAdapter {
@Override
public boolean preHandle(HttpServletRequest request,HttpServletResponse response,
Object handler) throws Exception {
//业务逻辑代码编写...(如:解决乱码,权限验证)
System.out.println("preHandle(), 在访问Controller之前被调用");
return true;
}
/**
* 在业务处理器处理请求执行完成后,生成视图之前执行的动作
* 可在modelAndView中加入数据，比如当前时间
*/
@Override
public void postHandle(HttpServletRequest request,HttpServletResponse response, Object handler,
ModelAndView modelAndView) throws Exception {
//业务逻辑代码编写...(如:操作日志记录,更改视图信息)
System.out.println("postHandle(), 在访问Controller之后，访问视图之前被调用,这里可以注入一个时间到modelAndView中，用于后续视图显示");
modelAndView.addObject("date","由拦截器生成的时间:" + new Date());
}
/**
* 在DispatcherServlet完全处理完请求后被调用,可用于清理资源等
* 当有拦截器抛出异常时,会从当前拦截器往回执行所有的拦截器的afterCompletion()
*/
@Override
public void afterCompletion(HttpServletRequest request,HttpServletResponse response,
Object handler, Exception ex) throws Exception {
//业务逻辑代码编写...(如:,资源销毁,异常处理)
System.out.println("afterCompletion(), 在访问视图之后被调用");
}
}