我查看了类似的问题，我遵循编写查询以插入数据库的语法，但我一直得到这个异常。我显然没有看到什么。它停止在＆＃34; insertStatement.setInt（1，schoolID）;＆＃34; 。我读到这意味着查询的语法不正确。请告诉我哪里出错了。我根本看不到它。
package Servlets;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;
import java.sql.Timestamp;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
import javax.servlet.ServletContext;
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 jpa.entities.School;
/**
*
* @author Timothy
*/
@WebServlet(name = "SchoolFormServlet", urlPatterns = {"/SchoolFormServlet"})
public class SchoolFormServlet extends HttpServlet {
/**
* Processes requests for both HTTP <code>GET</code> and <code>POST</code>
* methods.
*
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException, ParseException {
response.setContentType("text/html;charset=UTF-8");
try (PrintWriter out = response.getWriter()) {
/* TODO output your page here. You may use following sample code. */
ServletContext sc = this.getServletContext();
sc.getAttribute("schoolForm");
Integer schoolId = Integer.parseInt(request.getParameter("schoolID"));
String schoolName = request.getParameter("schoolName");
Integer periods = Integer.parseInt(request.getParameter("periods"));
Integer repeatDays = Integer.parseInt(request.getParameter("repeatDays"));
String scheduleBlock = request.getParameter("scheduleBlock");
Integer semesters = Integer.parseInt(request.getParameter("semesters"));
String rangeForLunch = request.getParameter("rangeForLunch");
String schoolYear = request.getParameter("schoolYear");
initAndExecuteQuery(schoolId,schoolName,semesters,periods,repeatDays,scheduleBlock,rangeForLunch,schoolYear);
out.println("<!DOCTYPE html>");
out.println("<html>");
out.println("<head>");
out.println("<title>Servlet SchoolFormServlet</title>");
out.println("</head>");
out.println("<body>");
out.println("<h1>Servlet SchoolFormServlet at " + request.getContextPath() + "</h1>");
out.println("</body>");
out.println("</html>");
}
}
// <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
/**
* Handles the HTTP <code>GET</code> method.
*
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
try {
processRequest(request, response);
} catch (ParseException ex) {
Logger.getLogger(SchoolFormServlet.class.getName()).log(Level.SEVERE, null, ex);
}
}
/**
* Handles the HTTP <code>POST</code> method.
*
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
try {
processRequest(request, response);
} catch (ParseException ex) {
Logger.getLogger(SchoolFormServlet.class.getName()).log(Level.SEVERE, null, ex);
}
}
/**
* Returns a short description of the servlet.
*
* @return a String containing servlet description
*/
@Override
public String getServletInfo() {
return "Short description";
}// </editor-fold>
public void initAndExecuteQuery(Integer schoolID,String schoolName, Integer semesters,Integer periods,Integer repeatDays,String scheduleBlock,String rangeForLunch, String schoolYear) {
// JDBC driver name and database URL
String jdbcDriver ="com.mysql.jdbc.Driver";
String url ="jdbc:mysql://173.194.104.102:3306/hssp_schema?zeroDateTimeBehavior=convertToNull";
Connection connection = null;
ResultSet resultSet = null;
Statement statement = null;
// Database credentials
String userName = "admin_aamir";
String passWord = "tommybrown";
try {
Class.forName("com.mysql.jdbc.Driver").newInstance();
connection = DriverManager.getConnection(url, userName , passWord);
// Execute SQL query
String sql;
sql = "INSERT INTO School VALUES ('"+schoolID+" ','"+schoolName+" ','"+semesters+" ','"+periods+" ','"+repeatDays+" ','"+scheduleBlock+" ','"+rangeForLunch+" ','"+schoolYear+" ')";
PreparedStatement insertStatement = connection.prepareStatement(sql);
insertStatement.setInt(1, schoolID);
insertStatement.setString(2,schoolName);
insertStatement.setInt(3,periods);
insertStatement.setInt(4,repeatDays);
insertStatement.setString(5,scheduleBlock);
insertStatement.setString(6,rangeForLunch);
insertStatement.setString(7,schoolYear);
insertStatement.executeQuery();
insertStatement.close();
connection.close();
}
catch (Exception e) {
e.printStackTrace();
}
}
}
答案 0 :(得分：1)
你需要在SQL字符串中加上问号，告诉它它有参数 - 而不是直接附加它们。
sql = "INSERT INTO School VALUES(?, ?, ? ...)
MySQL连接器实现将使用您设置的参数值替换这些问号（这不仅仅是将其粘贴到您的代码中，因为这会使其容易受到{{3 }}）。
答案 1 :(得分：1)
正确的语法是
INSERT INTO TABLENAME（FIELD1，FIELD2，FIELD3）VALUES（？，？，？）
所以你需要第一个parens中的列的名称和相同的数量？在第二。然后你的setX（1，value）语句填写问号在执行之前的位置。
答案 2 :(得分：0)
在School( ...... )里面放了你的数据库表列名，在values(?,?,?.....)里面根据你要插入数据库的列名放了问号，对于你当前的情况是8列所以放8个问题标记。
String sql;
sql = "INSERT INTO School(schoolID,schoolName,semesters,periods,repeatDays,scheduleBlock,rangeForLunch,schoolYear) VALUES (?,?,?,?,?,?,?,?)";
PreparedStatement insertStatement = connection.prepareStatement(sql);
insertStatement.setInt(1, schoolID);
insertStatement.setString(2,schoolName);
insertStatement.setInt(3,periods);
insertStatement.setInt(4,repeatDays);
insertStatement.setString(5,scheduleBlock);
insertStatement.setString(6,rangeForLunch);
insertStatement.setString(7,schoolYear);
// you have missing 1 line for number 8 , since you wanted to insert 8 data into 8 column
insertStatement.executeQuery();
insertStatement.close();
connection.close();
答案 3 :(得分：0)
方法1： 写下面的代码
String sql;
sql = "INSERT INTO School VALUES ('"+schoolID+" ','"+schoolName+" ','"+semesters+" ','"+periods+" ','"+repeatDays+" ','"+scheduleBlock+" ','"+rangeForLunch+" ','"+schoolYear+" ')";
PreparedStatement insertStatement = connection.prepareStatement(sql);
int valid = insertStatement.executeUpdate();
if(valid == 1)
System.out.println("insertion successfull");
else
System.out.println("problem while inserting data in database");
希望它适合你。它适用于我的情况。
方法2：
编写以下代码
String sql;
sql = "INSERT INTO School VALUES ('"+schoolID+" ','"+schoolName+" ','"+semesters+" ','"+periods+" ','"+repeatDays+" ','"+scheduleBlock+" ','"+rangeForLunch+" ','"+schoolYear+" ')";
sql = "INSERT INTO School VALUES(?,?,?,?,?,?,?,?)";
PreparedStatement insertStatement = connection.prepareStatement(sql);
insertStatement.setInt(1, schoolID);
insertStatement.setString(2,schoolName);
insertStatement.setInt(3,semesters) // you forgot to write this statement assuming the data types are correct
insertStatement.setInt(4,periods);
insertStatement.setInt(5,repeatDays);
insertStatement.setString(6,scheduleBlock);
insertStatement.setString(7,rangeForLunch);
insertStatement.setString(8,schoolYear);
int valid = insertStatement.executeUpdate();
if(valid == 1)
System.out.println("insertion successfull");
else
System.out.println("problem while inserting data in database");
希望您了解这两种方法