jsp 链接数据库出现空指针异常

Question

public static boolean login(User u){
Boolean a = false;
String sql = "select * from user where username=? and userpassword=?";
PreparedStatement pre=null;
try {
pre = (Tool.getCon()).prepareStatement(sql); // 该句出现异常
pre.setString(1,u.getUsername());
pre.setString(2,u.getUserpassword());
a=pre.execute();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println(a);
return a;
}

Answer 1

可以的话把你的整个项目发到我的邮箱，我运行一下。。。。。。。。