java mysql 中文乱码有关问题

java mysql 中文乱码问题求高手指教
做了一个登录界面以下是代码：
login.jsp

HTML code


<%@ page contentType="text/html; charset=gb2312"%>
<%
request.setCharacterEncoding("gb2312");
%>
<!-- 该Login页面是一个简单的登录界面 -->
<!--
 该JSP程序是用来测试与MySQL数据库的连接，
 需要一个数据库：LearnJSP，和其中一个表：userinfo
 表中有两个字段分别为：UserName varchar (20) not null,UserPwd varchar (20) not null
-->
<html>
  <head>
    <title>登录</title>
    <meta http-equiv="Content-Type" content="text/html; charset=gb2312">
    <meta http-equiv="Content-Language" content="ch-cn">
  </head>
  <body bgcolor=cyan>
 <!-- Form 用来提取用户填入并提交的信息-->
 <form method="POST" name="frmLogin" action="LoginServlet">
   <h1 align="center">用户登录</h1><br>
   <div align="center">用户名：
      <input type="text" name="txtUserName" value=""
       size="20" maxlength="20"
       onfocus="if(this.value=='Your name')this.value=";"><br>密码：
      <input type="password" name="txtPassword" value=""
       size="20" maxlength="20"
       onfocus="if(this.value=='Your password')this.value=";"><br>
      <input type="submit" name="Submit"　value="提交" onClick="validateLogin();" >
       &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
      <input type="reset" name="Reset" value="重置"><br>
   </div>
 </form>
 <!-- javaScript 函数 validateLogin(),用来验证用户名和密码是否为空 -->
    <script language="javaScript">
     function validateLogin()
     {
      var sUserName = document.frmLogin.txtUserName.value;
      var sPassword = document.frmLogin.txtPassword.value;
      if( sUserName=="" )
      {
       alert("请输入用户名！");
       return false;
      }
      if( sPassword=="" )
      {
       alert("请输入密码！");
       return false;
      }
     }
    </script>
  </body>
</html>

LoginServlet.java

Java code


/**
 * 该JSP程序是用来测试与MySQL数据库的连接，
 * 需要一个数据库：LearnJSP，和其中一个表：userinfo
 * 表中有两个字段分别为：UserName varchar (20) not null,UserPwd varchar (20) not null
 */
package zieckey.login.servlet;
import java.sql.Statement;
import java.io.IOException;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import javax.servlet.Servlet;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class LoginServlet extends HttpServlet implements Servlet
{
 public LoginServlet ()
 {
  // TODO Auto-generated constructor stub
 
 }
 /*
  * (non-Javadoc)
  *
  * @see javax.servlet.http.HttpServlet#doGet(javax.servlet.http.HttpServletRequest,
  * javax.servlet.http.HttpServletResponse)
  */
 @Override

 protected void doGet ( HttpServletRequest arg0, HttpServletResponse arg1 )
   throws ServletException, IOException
 {
     
 }
 /*
  * (non-Javadoc)
  *
  * @see javax.servlet.http.HttpServlet#doPost(javax.servlet.http.HttpServletRequest,
  * javax.servlet.http.HttpServletResponse)
  */
 @Override
 protected void doPost ( HttpServletRequest request, HttpServletResponse response )
   throws ServletException, IOException
 {
  response.setContentType ( "text/html;charset=GB2312" );
  String result = "";
  // 获取用户名

  String sUserName = request.getParameter ( "txtUserName" );
  if ( sUserName == "" || sUserName == null || sUserName.length ( ) > 20 )
  {
   try
   {
    result = "请输入用户名（不超过20字符）！";
    request.setAttribute ( "ErrorUserName", result );
    response.sendRedirect ( "login.jsp" );
   } catch ( Exception e )
   {
   }
  }
  // 获取密码

  String sPasswd = request.getParameter ( "txtPassword" );
  if ( sPasswd == "" || sPasswd == null || sPasswd.length ( ) > 20 )
  {
   try
   {
    result = "请输入密码（不超过20字符）！";
    request.setAttribute ( "ErrorPassword", result );
    response.sendRedirect ( "login.jsp" );
   } catch ( Exception e )
   {
   }
  }
  // 登记JDBC驱动程序

  try
  {
   Class.forName ( "org.gjt.mm.mysql.Driver" ).newInstance ( );
  } catch ( InstantiationException e )
  {
   // TODO Auto-generated catch block

   e.printStackTrace ( );
   System.out.println ("InstantiationException");
  } catch ( IllegalAccessException e )
  {
   // TODO Auto-generated catch block

   e.printStackTrace ( );
   System.out.println ("IllegalAccessException");
  } catch ( ClassNotFoundException e )
  {
   // TODO Auto-generated catch block

   e.printStackTrace ( );
   System.out.println ("ClassNotFoundException");
  }
  // 连接参数与Access不同
  String url = "jdbc:mysql://localhost:3306/LearnJSP";
  // 建立连接

  java.sql.Connection connection = null;
  Statement stmt = null;
  ResultSet rs = null;
  try
  {
   connection = DriverManager.getConnection ( url, "root", "root" );
   stmt = connection.createStatement ( );
   // SQL语句
   String sql = "select * from userinfo where username='" + sUserName
     + "' and userpwd = '" + sPasswd + "'";
   rs = stmt.executeQuery ( sql );// 返回查询结果

  } catch ( SQLException e )
  {
   // TODO Auto-generated catch block

   e.printStackTrace ( );
  }
  try
  {
   if ( rs.next ( ) )// 如果记录集非空，表明有匹配的用户名和密码，登陆成功

   {
    // 登录成功后将sUserName设置为session变量的UserName

    // 这样在后面就可以通过 session.getAttribute("UserName") 来获取用户名，

    // 同时这样还可以作为用户登录与否的判断依据

    request.getSession ( ).setAttribute ( "UserName", sUserName );
    response.sendRedirect ( "login_success.jsp" );
   } else
   {
    // 否则登录失败

    //response.sendRedirect ( "MyJsp.jsp" );

    request.getSession ( ).setAttribute ( "UserName", sUserName );
    response.sendRedirect ( "login_failure.jsp" );

   }
  } catch ( SQLException e )
  {
   // TODO Auto-generated catch block

   e.printStackTrace ( );
  }
  try
  {
   if ( null!=rs )
   {
    rs.close ( );
   }
   if ( null!=stmt )
   {
    stmt.close ( );
   }
   if ( null!=connection )
   {
    connection.close ( );
   }
  } catch ( SQLException e )
  {
   // TODO Auto-generated catch block

   e.printStackTrace ( );
  }
 }
 /**
  *
  */
 private static final long serialVersionUID = 1L;
}

java mysql 中文乱码有关问题

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