大家好，我正在尝试为我的 java 网站创建一个注册 servlet，但我收到了这个错误，我不明白，因为第 1 行没有任何内容。
Error.com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '',)' at line 1
这是我的 servlet 代码
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class CreateTutor
*/
@WebServlet("/CreateTutor")
public class CreateTutor extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public CreateTutor() {
super();
// TODO Auto-generated constructor stub
}
private String uniid = "";
private String name = "";
private String password = "";
private String email = "";
private int access_level = 3;
public void init() {
try {
Class.forName("com.mysql.jdbc.Driver");
Connection con =
DriverManager.getConnection("jdbc:mysql://localhost:3306/wae","root","");
System.out.println("JDBC driver loaded");
}
catch (ClassNotFoundException e) {
System.out.println(e.toString());
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
/**Process the HTTP Get request*/
public void doGet(HttpServletRequest request, HttpServletResponse response) throws
ServletException,IOException {
sendPageHeader(response);
sendRegistrationForm(request, response, false);
sendPageFooter(response);
}
/**Process the HTTP Post request*/
public void doPost(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
sendPageHeader(response);
uniid = request.getParameter("uniid");
name = request.getParameter("name");
password = request.getParameter("password");
email = request.getParameter("email");
boolean error = false;
String message = null;
try {
Class.forName("com.mysql.jdbc.Driver");
Connection con =
DriverManager.getConnection("jdbc:mysql://localhost:3306/wae","root","");
System.out.println("got connection");
Statement s = con.createStatement();
String sql = "SELECT name FROM user" +
" WHERE name='" + name + "'";
ResultSet rs = s.executeQuery(sql);
if (rs.next()) {
rs.close();
message = "The user name <B>" + name +
"</B> has been taken. Please select another name.";
error = true;
}
else {
rs.close();
sql = "INSERT INTO user" +
" (uniid, name, password, email, access_level)" +
" VALUES" +
" ('" + uniid + "'," +
" '" + name + "'," +
" '" + password + "'," +
" '" + email + "'," + access_level + "',)";
int i = s.executeUpdate(sql);
if (i==1) {
message = "Successfully added one user.";
}
}
s.close();
con.close();
}
catch (SQLException e) {
message = "Error." + e.toString();
error = true;
}
catch (Exception e) {
message = "Error." + e.toString();
error = true;
}
if (message!=null) {
PrintWriter out = response.getWriter();
out.println("<B>" + message + "</B><BR>");
out.println("<HR><BR>");
}
if (error==true)
sendRegistrationForm(request, response, true);
else
sendRegistrationForm(request, response, false);
sendPageFooter(response);
}
/**
* Send the HTML page header, including the title
* and the <BODY> tag
*/
private void sendPageHeader(HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("<HTML>");
out.println("<HEAD>");
out.println("<TITLE>Registration Page</TITLE>");
out.println("</HEAD>");
out.println("<BODY>");
out.println("<CENTER>");
}
/**
* Send the HTML page footer, i.e. the </BODY>
* and the </HTML>
*/
private void sendPageFooter(HttpServletResponse response)
throws ServletException, IOException {
PrintWriter out = response.getWriter();
out.println("</CENTER>");
out.println("</BODY>");
out.println("</HTML>");
}
/**Send the form where the user can type in
* the details for a new user
*/
private void sendRegistrationForm(HttpServletRequest request,
HttpServletResponse response, boolean displayPreviousValues)
throws ServletException, IOException {
PrintWriter out = response.getWriter();
out.println("<BR><H2>Registration Page</H2>");
out.println("<BR>Please enter the user details.");
out.println("<BR>");
out.println("<BR><FORM METHOD=POST>");
out.println("<TABLE>");
out.println("<TR>");
out.println("<TD>Uni Id</TD>");
out.print("<TD><INPUT TYPE=TEXT Name=uniid");
if (displayPreviousValues)
out.print(" VALUE=\"" + uniid + "\"");
out.println("></TD>");
out.println("</TR>");
out.println("<TR>");
out.println("<TD>Name</TD>");
out.print("<TD><INPUT TYPE=TEXT Name=name");
if (displayPreviousValues)
out.print(" VALUE=\"" + name + "\"");
out.println("></TD>");
out.println("</TR>");
out.println("<TR>");
out.println("<TD>Password</TD>");
out.print("<TD><INPUT TYPE=PASSWORD Name=password");
if (displayPreviousValues)
out.print(" VALUE=\"" + password + "\"");
out.println("></TD>");
out.println("</TR>");
out.println("<TR>");
out.println("<TD>Email</TD>");
out.print("<TD><INPUT TYPE=TEXT Name=email");
out.println("></TD>");
out.println("</TR>");
out.println("<TR>");
out.println("<TD>Access Level</TD>");
out.print("<TD><INPUT TYPE=int Name=access_level");
out.println("></TD>");
out.println("</TR>");
if (displayPreviousValues)
out.print(" VALUE=\"" + password + "\"");
out.println("></TD>");
out.println("</TR>");
out.println("<TR>");
out.println("<TD><INPUT TYPE=RESET></TD>");
out.println("<TD><INPUT TYPE=SUBMIT></TD>");
out.println("</TR>");
out.println("</TABLE>");
out.println("</FORM>");
out.println("<BR>");
out.println("<BR>");
}
}