                        课程
                    
                        /后端开发
                        
                            /Java
                        
                        /通过自动回复机器人学Mybatis---基础版

按老师的做，最后还是查不到

package com.test.servlet;

import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.test.bean.Message;
import com.test.conn.ConnectionFactory;

/**
* 列表页面初始化控制
* Servlet implementation class ListServlet
*/
@WebServlet("/ListServlet")
public class ListServlet extends HttpServlet {
   private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public ListServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

   /**
   * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
   */
   protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
       // TODO Auto-generated method stub

       try {

           request.setCharacterEncoding("UTF-8");
           String command = request.getParameter("command");
           String description = request.getParameter("description");

           Connection conn = ConnectionFactory.getConnection();
           StringBuilder sql=new StringBuilder("SELECT ID,COMMAND,DESCRIPTION,CONTENT FROM MESSAGE WHERE 1=1");

           List<String> paramList=new ArrayList<String>();
           if(command !=null && !"".equals(command.trim())){
               sql.append(" and COMMAND=?");
               paramList.add(command);
           }
           if(description !=null && !"".equals(description.trim())){
               sql.append(" and DESCRIPTION like '%'?'%'");
               paramList.add(description);
           }
           PreparedStatement ps = conn.prepareStatement(sql.toString());
           for (int i=0;i<paramList.size();i++){
               ps.setString(i+1, paramList.get(i));
           }
           ResultSet rs = ps.executeQuery();
           List<Message> messageList = new ArrayList<Message>();
           while(rs.next()){
               Message message = new Message();
               messageList.add(message);
               message.setCommand(rs.getString("COMMAND"));
               message.setId(rs.getString("ID"));
               message.setDescription(rs.getString("DESCRIPTION"));
               message.setContent(rs.getString("CONTENT"));
           }
           request.setAttribute("messageList", messageList);
       } catch (SQLException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }
       request.getRequestDispatcher("/WEB-INF/jsp/back/list.jsp").forward(request,response);
   }

   /**
   * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
   */
   protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
       // TODO Auto-generated method stub
       this.doGet(request, response);
   }

}