不好意思,粘贴错误,以下是正确代码:
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.util.*;
import java.sql.*;public class TestDB extends HttpServlet{
public void doGet(HttpServletRequest request,
HttpServletResponse response)
throws ServletException,IOException{
response.setContentType("text/html");
PrintWriter out = response.getWriter();
showResult(request,out);
}private void showResult(HttpServletRequest request,PrintWriter out){
String sname = request.getParameter("sname");
try
{
Class.forName("org.gjt.mm.mysql.Driver");
String dburl = "jdbc:mysql://localhost/test";
Connection c = DriverManager.getConnection(dburl, "", "");
Statement stat = c.createStatement();
ResultSet result = stat.executeQuery("select Sno from student where Sname=sname");
String Sno = result.getString(1);
result.next();
out.println("<html>");
out.println("<head><title>Result</title></head>");
out.println("<body>");
out.println("<h1>");
out.println("The Student's ID is:");
out.println("</h1>");
out.println("<h1>" );
out.println(Sno);
out.println("</h1>");
out.println("</body></html>");
result.close();
}
catch(SQLException e)
{
System.out.println(e);
}
catch(ClassNotFoundException e)
{
System.out.println(e);
}
catch(Exception e)
{
System.out.println(e);}
}
}
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.util.*;
import java.sql.*;public class TestDB extends HttpServlet{
public void doGet(HttpServletRequest request,
HttpServletResponse response)
throws ServletException,IOException{
response.setContentType("text/html");
PrintWriter out = response.getWriter();
showResult(request,out);
}private void showResult(HttpServletRequest request,PrintWriter out){
String sname = request.getParameter("sname");
try
{
Class.forName("org.gjt.mm.mysql.Driver");
String dburl = "jdbc:mysql://localhost/test";
Connection c = DriverManager.getConnection(dburl, "", "");
Statement stat = c.createStatement();
ResultSet result = stat.executeQuery("select Sno from student where Sname=sname");
String Sno = result.getString(1);
result.next();
out.println("<html>");
out.println("<head><title>Result</title></head>");
out.println("<body>");
out.println("<h1>");
out.println("The Student's ID is:");
out.println("</h1>");
out.println("<h1>" );
out.println(Sno);
out.println("</h1>");
out.println("</body></html>");
result.close();
}
catch(SQLException e)
{
System.out.println(e);
}
catch(ClassNotFoundException e)
{
System.out.println(e);
}
catch(Exception e)
{
System.out.println(e);}
}
}
解决方案 »
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result.next();
这里不会有错吗
while(result.next()){
String Sno = result.getString(1);
}
String sql;
sql="select Sno from student where Sname='"+sname+"'";
ResultSet result = stat.executeQuery(sql);
这个问题的确是代码错了,就是缺少result.next()语句。