狂神说Java【SMBMS】——SMBMS超市订单管理系统(三) ——登陆功能优化
1、注销功能
思路:移除session对象+返回登陆页面
1.编写servlet
package com.thhh.servlet.user;
import com.thhh.utils.Constants;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
public class LogoutServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
req.getSession().removeAttribute(Constants.USER_SESSION);//移除用户session
resp.sendRedirect(req.getContextPath()+"/login.jsp");//重定向回登陆页面
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
doGet(req, resp);
}
}
2.注册servlet
<!--注册注销servlet-->
<servlet>
<servlet-name>LogoutServlet</servlet-name>
<servlet-class>com.thhh.servlet.user.LogoutServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>LogoutServlet</servlet-name>
<url-pattern>/jsp/logout.do</url-pattern>
</servlet-mapping>
2、登陆拦截优化
1.编写过滤器
package com.thhh.filter;
import com.thhh.pojo.User;
import com.thhh.utils.Constants;
import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
public class SysFilter implements Filter {
@Override
public void init(FilterConfig filterConfig) throws ServletException {
}
@Override
public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws IOException, ServletException {
HttpServletRequest request = (HttpServletRequest)req;//父类强转子类,用于获取session
HttpServletResponse response = (HttpServletResponse) resp;//父类强转子类,用于重定向
User user = (User) request.getSession().getAttribute(Constants.USER_SESSION);
if (user==null){//用户处于未登陆状态
response.sendRedirect(request.getContextPath()+"/error.jsp");//重定向到登陆页面
}else{
chain.doFilter(req,resp);//过滤器放行
}
}
@Override
public void destroy() {
}
}
2.注册过滤器
<!--注册未登录时请求后台页面过滤器-->
<filter>
<filter-name>SysFilter</filter-name>
<filter-class>com.thhh.filter.SysFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>SysFilter</filter-name>
<url-pattern>/jsp/*</url-pattern>
<!--注意:我们将所有需要登陆之后才能访问的功能性页面给都放在了/jsp文件夹下,所以过滤器应该过滤这个文件夹下的请求-->
</filter-mapping>
3.导入error页面
4.测试功能
测试完成!