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
public class LoginInterceptor implements HandlerInterceptor {
@Override
public void afterCompletion(HttpServletRequest request,
HttpServletResponse response, Object obj, Exception err)
throws Exception {
}
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response,
Object obj, ModelAndView mav) throws Exception {
}
@Override
public boolean 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){
return true;
}
//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");
return false;
}
}
Controller代码
@Controller
@RequestMapping("/backend")
public class BackendController {
@RequestMapping(value = "/loginPage", method = {RequestMethod.GET})
public String loginPage(HttpServletRequest request,String account, String password){
return "login";
}
@RequestMapping(value = "/login", method = {RequestMethod.POST})
public String 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})
public String loginOut(HttpServletRequest request) {
request.getSession().removeAttribute("isLogin");
return "redirect:loginPage";
}
@RequestMapping(value = "/IndexPage", method = {RequestMethod.GET})
public String IndexPage(HttpServletRequest request){
return "Index";
}
}
spring的配置
<!--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:mapping path="/backend/**"/>
<!--不拦截登录页和登录的请求-->
<mvc:exclude-mapping path="/backend/loginPage"/>
<mvc:exclude-mapping path="/backend/login"/>
<bean class="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
public class LoginInterceptor implements HandlerInterceptor {
@Override
public void afterCompletion(HttpServletRequest request,
HttpServletResponse response, Object obj, Exception err)
throws Exception {
}
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response,
Object obj, ModelAndView mav) throws Exception {
}
@Override
public boolean 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")){
return true;
}
}
}
// 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");
return false;
}
}
Controller的变化也不大
@Controller
@RequestMapping("/backend")
public class BackendController {
@RequestMapping(value = "/loginPage", method = {RequestMethod.GET})
public String loginPage(HttpServletRequest request, String account, String password) {
return "login";
}
@RequestMapping(value = "/login", method = {RequestMethod.POST})
public String 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})
public String 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})
public String IndexPage(HttpServletRequest request) {
return "Index";
}
}
spring的配置和之前的一模一样
注意
这里只是演示,建议在实际项目中Cookie的键和值要经过特殊处理，否则会引发安全问题
