提交数据问题
为了向数据库中插入一个新条目，代码如下：
Connection conn = null;
Class.forName( "com.mysql.jdbc.Driver ").newInstance();
String url = "jdbc:mysql://localhost/mysqldb？user=abc&password=123&useUnicode=true&characterEncoding=gb2312 ";
conn = DriverManager.getConnection(url);
Statement stmt=conn.createStatement();
String sql= "insert meetuser(userid,userpass,username,campaign_id) values( ' "+request.getParameter( "userid ")+ " ', ' "+request.getParameter( "userpass ")+ " ', ' "+request.getParameter( "username ")+ " ', ' "+request.getParameter( "campaign ")+ " ') ";
stmt.executeQuery(sql);

但抛出异常
javax.servlet.ServletException: Can not issue data manipulation statements with executeQuery().

请问是什么问题？

[解决办法]
stmt.executeQuery(sql);
改成
stmt.executeUpdate(sql);
[解决办法]
你的SQL拼写错误，用这个：
String sql = "insert meetuser(userid,userpass,username,campaign_id) values( "+ "request.getParameter( 'userid ') "+ ", "+ "request.getParameter( 'userpass ') "+ ", "+ "request.getParameter( 'username ') "+ ", "+ "request.getParameter( 'campaign ') "+ ") ";