1.拦截器
SpringMvc中的拦截器实现了HandlerInterceptor接口,通常使用与身份认证,授权和校验,模板视图,统一处理等;
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public class HanderInterceptor1 implements HandlerInterceptor { @Override public void afterCompletion(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, Exception arg3) throws Exception { } @Override public void postHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, ModelAndView arg3) throws Exception { } @Override public boolean preHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2) throws Exception { return true ; } } |
在拦截器中有三个方法 :
preHandler :在进入Handler方法之前执行了,使用于身份认证,身份授权,登陆校验等,比如身份认证,用户没有登陆,拦截不再向下执行,返回值为 false ,即可实现拦截;否则,返回true时,拦截不进行执行;
postHandler : 进入Handler方法之后,返回ModelAndView之前执行,使用场景从ModelAndView参数出发,比如,将公用的模型数据在这里传入到视图,也可以统一指定显示的视图等;
afterHandler : 在执行Handler完成后执行此方法,使用于统一的异常处理,统一的日志处理等;
2.拦截器的配置
拦截器的配置有两种方式实现 :
(1)针对某个handlermapping (controller)的 配置
Springmvc拦截器针对某个controller进行拦截设置,如果在某个HandlerMapping中配置拦截,经过该HandlerMapping映射成功的handler最终使用该拦截器;
(2)类似全局的配置
可以配置类似全局的拦截器,springmvc框架将配置的类似全局拦截器注入到每个Handlermapping中;
配置实现 :
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<!-- 配置拦截器 --> < mvc:interceptors > <!-- 多个拦截器,顺序执行 --> < mvc:interceptor > <!-- /** 表示所有的url,包括子url路径 --> < mvc:mapping path = "/**" /> < bean class = "cn.labelnet.ssm.filter.HanderInterceptor1" ></ bean > </ mvc:interceptor > <!-- 配置登陆拦截器 --> < mvc:interceptor > < mvc:mapping path = "/**" /> < bean class = "cn.labelnet.ssm.filter.LoginHandlerIntercepter" ></ bean > </ mvc:interceptor > <!-- ..... --> </ mvc:interceptors > |
(3)在一个工程中,可以配置多个拦截器,使用多个拦截器,则要注意的是 :
多个拦截器使用的时候,preHandler是顺序执行的,而postHandler和afterHandler是倒序执行的;
所以 :
如果统一日志处理器拦截器,需要改拦截器prehandler一定要返回true,且将它放在拦截器配置的第一个位置;
如果登陆认证拦截器,放在拦截器的配置中的第一个位置(有日志处理的话,放在日志处理下面);
如果有权限校验拦截器,则放在登陆拦截器之后,因为登陆通过后,才可以进行校验权限;
3.示例:
场景描述 :用户点击查看的时候,我们进行登陆拦截器操作,判断用户是否登陆? 登陆,则不拦截,没登陆,则转到登陆界面;
图示 :
3.1 controller 登陆业务实现
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@RequestMapping ( "/clientLogin" ) public String clientLogin(HttpSession httpSession,String username,String password){ if (username.equals( "yuan" )&&password.equals( "123456" )){ //登陆成功 httpSession.setAttribute( "username" ,username); return "forward:clientsList.action" ; } else { //登陆失败 return "forward:login.jsp" ; } } |
3.2 controller 登出业务实现
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@RequestMapping ( "/clientLoginOut" ) public String clientLoginOut(HttpSession httpSession){ httpSession.invalidate(); return "forward:clientsList.action" ; } |
3.3 拦截器实现
在这里实现用户拦截实现是:通过判断是否是编辑查看的页面,如果是,判断session中的用户名存在不存在,就可以了;
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package cn.labelnet.ssm.filter; 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; /** * 登陆拦截器 * 场景:用户点击查看的时候,我们进行登陆拦截器操作,判断用户是否登陆? * 登陆,则不拦截,没登陆,则转到登陆界面; * TODO * 作者:原明卓 * 时间:2016年1月8日 下午3:25:35 * 工程:SpringMvcMybatis1Demo */ public class LoginHandlerIntercepter implements HandlerInterceptor { @Override public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object arg2, Exception arg3) throws Exception { } @Override public void postHandle(HttpServletRequest arg0, HttpServletResponse arg1, Object arg2, ModelAndView arg3) throws Exception { } @Override public boolean preHandle(HttpServletRequest request, HttpServletResponse arg1, Object arg2) throws Exception { String requestURI = request.getRequestURI(); if (requestURI.indexOf( "editClientIfo.action" )> 0 ){ //说明处在编辑的页面 HttpSession session = request.getSession(); String username = (String) session.getAttribute( "username" ); if (username!= null ){ //登陆成功的用户 return true ; } else { //没有登陆,转向登陆界面 request.getRequestDispatcher( "/login.jsp" ).forward(request,arg1); return false ; } } else { return true ; } } } |
3.4 拦截器配置实现
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<!-- 配置拦截器 --> < mvc:interceptors > <!-- 多个拦截器,顺序执行 --> < mvc:interceptor > <!-- /** 表示所有的url,包括子url路径 --> < mvc:mapping path = "/**" /> < bean class = "cn.labelnet.ssm.filter.HanderInterceptor1" ></ bean > </ mvc:interceptor > <!-- 配置登陆拦截器 --> < mvc:interceptor > < mvc:mapping path = "/**" /> < bean class = "cn.labelnet.ssm.filter.LoginHandlerIntercepter" ></ bean > </ mvc:interceptor > <!-- ..... --> </ mvc:interceptors > |
3.5 登陆页面实现
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<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%> <% String path = request.getContextPath(); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> < html > < head > < base href="<%=basePath%>" rel="external nofollow" > < title >用户登陆</ title > < meta http-equiv = "pragma" content = "no-cache" > < meta http-equiv = "cache-control" content = "no-cache" > < meta http-equiv = "expires" content = "0" > < meta http-equiv = "keywords" content = "keyword1,keyword2,keyword3" > < meta http-equiv = "description" content = "This is my page" > <!-- <link rel="stylesheet" type="text/css" href="styles.css" rel="external nofollow" > --> </ head > < body > < form action = "${pageContext.request.contextPath }/clients/clientLogin.action" method = "post" > 姓名:< input type = "text" name = "username" > < br >< br > 密码: < input type = "text" name = "password" > < br >< br > < input type = "submit" value = "登陆" > </ form > </ body > </ html > |
3.6 列表信息页面
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< body > < h1 >客户信息管理 < br > < c:if test = "${username!=null }" > ${username} < a href = "${pageContext.request.contextPath}/clients/clientLoginOut.action" rel = "external nofollow" >退出</ a > </ c:if > </ h1 > < form method = "post" action = "" style = "margin-top: 10px;float: left;margin-left: 5%;" > < input id = "search" type = "text" > < input value = "查询" type = "submit" > </ form > < table width = "90%" border = "1" align = "center" > < thead > < tr > < td colspan = "10" align = "center" > 客户信息管理</ td > </ tr > </ thead > < tbody > < tr align = "center" > < td >编号</ td > < td >姓名</ td > < td >代码</ td > < td >生日</ td > < td >家庭住址</ td > < td >现居住地</ td > < td >联系方式</ td > < td >紧急联系方式</ td > < td >注册日期</ td > < td >操作</ td > </ tr > < c:forEach items = "${clients}" var = "c" > < tr > < td > ${c.id} </ td > < td > ${c.username} </ td > < td > ${c.client_certificate_no} </ td > < td > ${c.born_date} </ td > < td > ${c.family_register_address} </ td > < td > ${c.now_address} </ td > < td > ${c.contact_mode} </ td > < td > ${c.urgency_contact_mode} </ td > < td > ${c.create_date} </ td > < td >< a href = "${pageContext.request.contextPath}/clients/editClientIfo.action?id=${c.id}" rel = "external nofollow" >查看</ a ></ td > </ tr > </ c:forEach > </ tbody > </ table > </ body > |
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原文链接:http://www.cnblogs.com/cnblog-long/p/6554654.html