查不出来QAQ。

Question

package com.lzh.servlet;import java.io.IOException;import java.sql.Connection;import java.sql.DriverManager;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.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import com.lzh.bean.Message;/** *  * 列表页面初始化设置 * */@SuppressWarnings("serial")public class ListServlet extends HttpServlet{@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { try { req.setCharacterEncoding("UTF-8"); String command = req.getParameter("command"); String description = req.getParameter("description"); req.setAttribute("command", command); req.setAttribute("description", description); Class.forName("com.mysql.jdbc.Driver"); Connection conn = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/webee","root","123456"); StringBuilder sql =new StringBuilder( "select ID,COMMAND,DESCRIPTION,CONTENT from t_message where 1=1"); List<String> paramList = new ArrayList<String>(); if(command!= null&&!"".equals(command.trim())){ sql.append(" and COMMAND=? "); } if(description!= null&&!"".equals(description.trim())){ sql.append("and DESCRIPTION like '%' ? '%' "); paramList.add(description); } PreparedStatement statement = conn.prepareStatement(sql.toString()); for(int i=0;i<paramList.size();i++){ statement.setString(i+1, paramList.get(i)); } ResultSet rs =statement.executeQuery(); List<Message> messageList = new ArrayList<Message>(); while(rs.next()){ Message message = new Message(); messageList.add(message); message.setId(rs.getString("ID")); message.setCommand(rs.getString("COMMAND")); message.setDescription(rs.getString("DESCRIPTION")); message.setContent(rs.getString("CONTENT")); } req.setAttribute("messageList", messageList); } catch (ClassNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } req.getRequestDispatcher("/WEB-INF/jsp/back/list.jsp").forward(req, resp);}@Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { this.doGet(req, resp); }}控制台报这个错 No value specified for parameter 1