做项目错误记录

我就是我 2024-03-16 18:23 22阅读 0赞

## UserServlet 中出错 ##

package com.dong.sys.servlet;
    
    import com.dong.sys.bean.SysUser;
    import com.dong.sys.service.IUserService;
    import com.dong.sys.service.impl.UserServiceImpl;
    
    import javax.servlet.*;
    import javax.servlet.http.*;
    import javax.servlet.annotation.*;
    import java.io.IOException;
    import java.util.List;
    
    /**
     * 处理客户端对用户的请求
     */
    @WebServlet("/userServlet")
    public class UserServlet extends HttpServlet {
    
        private IUserService service=new UserServiceImpl();
    
        @Override
        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            this.doPost(request,response);
        }
    
        @Override
        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
            //让客户端提供一个具体的请求的标识符
            String action = (String) request.getAttribute("action");
    
            if ("save".equals(action)){
                //表示添加数据
    
                //获取客户端提交的数据
                String username = request.getParameter("username");
                String password = request.getParameter("password");
                String nickname = request.getParameter("nickname");
    
                SysUser user=new SysUser();
                user.setUsername(username);
                user.setPassword(password);
                user.setNickname(nickname);
    
                //调用service方法完成数据的存储
                service.save(user);
    
            }else if("addOrUpdatePage".equals(action)){
                //表示需要进入到addOrUpdate.jsp页面
                request.getRequestDispatcher("/sys/user/addOrUpdate.jsp").forward(request,response);
            }else {
                //表示查询数据
    
                // 查询所有的用户信息
                List<SysUser> list = service.list(null);
    
                // 把查询到的用户数据储存到request的作用域中
                request.setAttribute("list",list);
    
                //通过服务端转发的方式跳转页面
                request.getRequestDispatcher("/sys/user/list.jsp").forward(request,response);
            }
        }
    }

![f0d5782f39864647a66b712feb4ae4bb.png][]

![2bc4bf7424ef468e9a993bcec54e901b.png][]

### 解决： ###

>  **应该使用 `request.getParameter("action")`获取客户端提交的动作标识符 `action`。**

### 运行结果： ###

添加成功！！！！

![199177702c6d49df95762a84ab6f05ff.png][]

[f0d5782f39864647a66b712feb4ae4bb.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/15/e13a0c4cb2394facb71f508dc38ee2a8.png
[2bc4bf7424ef468e9a993bcec54e901b.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/15/ffb9d655d4b74727b5d7699442b86c96.png
[199177702c6d49df95762a84ab6f05ff.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/15/0f50cf44d5d447a0a88c354ae71a86bd.png