标签:ram component col let oca 必须 rect mode after
##什么是拦截器
spring提供的一个特殊的组件,当DispatcherServlet收到请求后,如果有拦截器,会先调用拦截器,然后调用相应的处理器(Controler)。
注:过滤器属于servlet规范,而拦截器属于spring框架。
##如何写一个拦截器
1.写一个Java类,实现HandlerInterceptor接口。
2.实现具体的拦截处理逻辑,比如,session验证。
3.配置拦截器。
package com.outlook.menbozg.interceptors; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import org.springframework.web.servlet.HandlerInterceptor; import org.springframework.web.servlet.ModelAndView; public class SessionInterceptor implements HandlerInterceptor{ public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { System.out.println("preHandler()"); HttpSession session = request.getSession(); Object object = session.getAttribute("admin"); if(object == null) { //没有登陆,重定向到登陆页面 response.sendRedirect("toLogin.form"); return false; } //已经登陆过,则允许访问。 return true; } public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception { } public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception { } }
<?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:context="http://www.springframework.org/schema/context" xmlns:jdbc="http://www.springframework.org/schema/jdbc" xmlns:jee="http://www.springframework.org/schema/jee" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:aop="http://www.springframework.org/schema/aop" xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:util="http://www.springframework.org/schema/util" xmlns:jpa="http://www.springframework.org/schema/data/jpa" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc-3.2.xsd http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-3.2.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.2.xsd http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa-1.3.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.2.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.2.xsd"> <!-- 配置组件扫描 --> <context:component-scan base-package="com.outlook.menbozg"></context:component-scan> <!-- 配置mvc注解扫描 --> <mvc:annotation-driven></mvc:annotation-driven> <!-- 配置视图解析器 --> <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="prefix" value="/WEB-INF/"></property> <property name="suffix" value=".jsp"></property> </bean> <util:properties id="jdbc" location="classpath:db.properties" /> <!-- 配置连接池 --> <bean id="ds" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close"> <property name="driverClassName" value="#{jdbc.driverclass}" /> <property name="url" value="#{jdbc.url}" /> <property name="username" value="#{jdbc.user}" /> <property name="password" value="#{jdbc.password}" /> <property name="maxActive" value="#{jdbc.maxActive}"/> </bean> <!-- 配置拦截器 --> <mvc:interceptors> <mvc:interceptor> <mvc:mapping path="/**" /> <mvc:exclude-mapping path="/toLogin.form"/> <mvc:exclude-mapping path="/login.form"/> <bean class="com.outlook.menbozg.interceptors.SessionInterceptor"></bean> </mvc:interceptor> </mvc:interceptors> </beans>
## spring异常处理
可以将异常抛给spring,由spring来处理这些异常
具体有两个方法:
## 使用spring简单异常处理器
##注解
@ExceptionHandler
1. 在处理器类中,添加一个异常处理方法,该方法必须使用@ExceptionHandler修饰。
注:在该方法里面,依据异常类型,分别进行不同的处理。
2.添加异常处理页面。
标签:ram component col let oca 必须 rect mode after
原文地址:https://www.cnblogs.com/menbozg/p/11486521.html