使用session和cookie实现免登陆

来源：互联网发布：动物大百科软件下载编辑：程序博客网时间：2024/05/17 03:48

原文链接：http://www.jb51.net/article/108764.htm

参考文件：http://blog.csdn.net/a997208868/article/details/47787305

后台管理页面往往需要登录才可以进行操作，这时就需要Seession来记录登录状态

要实现起来也是非常简单，只需要自定义一个HandlerInterceptor就行了

自定义的HandlerInterceptor也只有短短几行代码

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public class LoginInterceptor implementsHandlerInterceptor {
 
  @Override
  publicvoid afterCompletion(HttpServletRequest request,
                HttpServletResponse response, Object obj, Exception err)
      throwsException {
  }
 
  @Override
  publicvoid postHandle(HttpServletRequest request, HttpServletResponse response,
              Object obj, ModelAndView mav)throws Exception {
 
  }
 
  @Override
  publicboolean preHandle(HttpServletRequest request, HttpServletResponse response,
               Object obj)throws Exception {
    //获取session里的登录状态值
    String str = (String) request.getSession().getAttribute("isLogin");
    //如果登录状态不为空则返回true，返回true则会执行相应controller的方法
    if(str!=null){
      returntrue;
    }
    //如果登录状态为空则重定向到登录页面，并返回false，不执行原来controller的方法
    response.sendRedirect("/backend/loginPage");
    returnfalse;
  }
}

Controller代码

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@Controller
@RequestMapping("/backend")
public class BackendController {
 
  @RequestMapping(value ="/loginPage", method = {RequestMethod.GET})
  publicString loginPage(HttpServletRequest request,String account, String password){
    return"login";
  }
 
  @RequestMapping(value ="/login", method = {RequestMethod.POST})
  publicString login(HttpServletRequest request,RedirectAttributes model, String account, String password){
    //验证账号密码，如果符合则改变session里的状态，并重定向到主页
    if("jack".equals(account)&&"jack2017".equals(password)){
      request.getSession().setAttribute("isLogin","yes");
      return"redirect:IndexPage";
    }else{
      //密码错误则重定向回登录页，并返回错误，因为是重定向所要要用到RedirectAttributes
      model.addFlashAttribute("error","密码错误");
      return"redirect:loginPage";
    }
  }
  //登出，移除登录状态并重定向的登录页
  @RequestMapping(value ="/loginOut", method = {RequestMethod.GET})
  publicString loginOut(HttpServletRequest request) {
    request.getSession().removeAttribute("isLogin");
    return"redirect:loginPage";
  }
  @RequestMapping(value ="/IndexPage", method = {RequestMethod.GET})
  publicString IndexPage(HttpServletRequest request){
    return"Index";
  }
 
}

spring的配置

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<!--省略其他基本配置-->
 
<!-- 配置拦截器 -->
<mvc:interceptors>
  <!-- 配置登陆拦截器 -->
  <mvc:interceptor>
    <!--拦截后台页面的请求-->
    <mvc:mappingpath="/backend/**"/>
    <!--不拦截登录页和登录的请求-->
    <mvc:exclude-mappingpath="/backend/loginPage"/>
    <mvc:exclude-mappingpath="/backend/login"/>
    <beanclass="com.ima.Interceptor.LoginInterceptor"></bean>
  </mvc:interceptor>
</mvc:interceptors>

一个简单的Session实现登录认证系统就这样完成了，如果想登录状态退出浏览器后仍保留一段时间的可以将Session改为Cookie

一般情况下我们都会使用Cookie

Cookie和Session的方法差不多

使用Cookie的自定义HandlerInterceptor

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public class LoginInterceptor implementsHandlerInterceptor {
 
  @Override
  publicvoid afterCompletion(HttpServletRequest request,
                HttpServletResponse response, Object obj, Exception err)
      throwsException {
  }
 
  @Override
  publicvoid postHandle(HttpServletRequest request, HttpServletResponse response,
              Object obj, ModelAndView mav)throws Exception {
 
  }
 
  @Override
  publicboolean preHandle(HttpServletRequest request, HttpServletResponse response,
               Object obj)throws Exception {
//    获取request的cookie
    Cookie[] cookies = request.getCookies();
    if(null==cookies) {
      System.out.println("没有cookie==============");
    }else {
//      遍历cookie如果找到登录状态则返回true执行原来controller的方法
      for(Cookie cookie : cookies){
        if(cookie.getName().equals("isLogin")){
          returntrue;
        }
      }
    }
//    没有找到登录状态则重定向到登录页，返回false，不执行原来controller的方法
    response.sendRedirect("/backend/loginPage");
    returnfalse;
  }
}

Controller的变化也不大

@Controller
@RequestMapping("/backend")
public class BackendController {
 
  @RequestMapping(value ="/loginPage", method = {RequestMethod.GET})
  publicString loginPage(HttpServletRequest request, String account, String password) {
    return"login";
  }
 
  @RequestMapping(value ="/login", method = {RequestMethod.POST})
  publicString login(HttpServletRequest request, HttpServletResponse response, RedirectAttributes model, String account, String password) {
    if("edehou".equals(account) &&"aidou2017".equals(password)) {
      Cookie cookie =new Cookie("isLogin","yes");
      cookie.setMaxAge(30* 60);// 设置为30min
      cookie.setPath("/");
      response.addCookie(cookie);
      return"redirect:IndexPage";
    }else {
      model.addFlashAttribute("error","密码错误");
      return"redirect:loginPage";
    }
  }
 
  @RequestMapping(value ="/logOut", method = {RequestMethod.GET})
  publicString loginOut(HttpServletRequest request, HttpServletResponse response) {
    Cookie[] cookies = request.getCookies();
    for(Cookie cookie : cookies) {
      if(cookie.getName().equals("isLogin")) {
        cookie.setValue(null);
        cookie.setMaxAge(0);// 立即销毁cookie
        cookie.setPath("/");
        response.addCookie(cookie);
        break;
      }
    }
    return"redirect:loginPage";
  }
 
  @RequestMapping(value ="/IndexPage", method = {RequestMethod.GET})
  publicString IndexPage(HttpServletRequest request) {
    return"Index";
  }
 
}

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