com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception: 

** BEGIN NESTED EXCEPTION ** 

java.net.SocketException
MESSAGE: Connection reset

STACKTRACE:

java.net.SocketException: Connection reset
  at java.net.SocketInputStream.read(SocketInputStream.java:168)
......
......
数据连接出错,请确保用户名，密码和服务器名没有错误

<%@ page import="java.sql.*,java.util.*" %><%@ page contentType="text/html;charset=UTF-8"%><% 
  java.sql.Connection sqlConn; 
  java.sql.Statement sqlStmt; 
  java.sql.ResultSet sqlRst; 
  try{
    Class.forName("org.gjt.mm.mysql.Driver").newInstance(); 
    sqlConn=java.sql.DriverManager.getConnection("jdbc:mysql://ip:3306/mintel?useUnicode=true&characterEncoding=UTF-8", "readonly","readonly"); 
    sqlStmt=sqlConn.createStatement();

    out.println("<p  align=center>数据库连接正常.");
    try{
      String query="select userId from nd_users";
      ResultSet rs =sqlStmt.executeQuery(query);
      int i=0;
      while(rs.next()){
        i++;
      }
      out.println("<br  align=center>"+"查询到的数据条目:"+i);
      rs.close();

    }catch(Exception ex){
      out.println("<p  align=center>"+ex.toString());
      out.println("<p  align=center><font color=red>数据查询出错</font>");
    }
    sqlStmt.close();
    sqlConn.close();

  }catch(Exception e){
    out.println("<p align=center>"+e.toString());
    out.println("<p  align=center><font color=red>数据连接出错,请确保用户名，密码和服务器名没有错误</font>");
  }
    
  out.println("<br><br>");

%>