驱动加载不成功,数据库连接失败...求助

[唬人的小怪兽]

在下萌新请大家帮忙看看 ,不知道为什么驱动加载不成功,数据库连接也不成功!

package tushu;

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

public class dengluyanzheng extends HttpServlet {
public void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException{
request.setCharacterEncoding("UTF-8");
String driverName="com.microsoft.sqlserver.jdbc.SQLServerDriver";
String dbURL="jdbc:sqlserver://localhost:1433;DatabaseName=yonghu";
String userName="sa";
String userPwd="123456";
String use=request.getParameter("use");
String pwd=request.getParameter("mima");
PrintWriter out=response.getWriter();

try {
Class.forName(driverName);
System.out.println("加载驱动成功");
}
catch(Exception e) {
e.printStackTrace();
System.out.println("加载驱动失败");
}
try {
Connection dbconn=DriverManager.getConnection(dbURL, userName, userPwd);
System.out.println("数据库连接成功");
Statement st=dbconn.createStatement();
ResultSet rs=st.executeQuery("select * form 用户");

while(rs.next()) {
String use1=rs.getString("学号");
String pwd1=rs.getString("密码");
if(use==use1&&pwd==pwd1)
{
request.getRequestDispatcher("/zhujiemian.jsp").forward(request, response);
}
}
}
catch(Exception e){
e.printStackTrace();
System.out.println("数据库连接失败");
}
}

}