MyEclipse链接mysql数据库问题，请高人指点，急

【请问我数据库连上了吗，这是什么意思？如果没连上怎么连呢，】
信息: Jk running ID=0 time=0/27  config=null
2011-12-7 14:45:51 org.apache.catalina.startup.Catalina start
信息: Server startup in 541 ms
database connection exception!
java.lang.NullPointerException
	at com.jxbsu.dao.UserDao.isValidUser(UserDao.java:17)
	at org.apache.jsp.deal_jsp._jspService(deal_jsp.java:79)
	at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
	at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:393)
	at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:320)
	at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:266)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:230)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:261)
	at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
	at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:581)
	at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
	at java.lang.Thread.run(Thread.java:619)

答案：空指针异常 对象没有初始化，就是说没有 new 对象就已经用了

其他：没有连接上、、

package com.ambo.jdbc.conn;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

public  class  MySqlConnection{


	public static Connection GetConnect()｛
		Connection conn =null;
		// TODO Auto-generated method stub
		String driver= "com.mysql.jdbc.Driver";
		String url = "jdbc:mysql://localhost:3306/DBname";
		String name = "root";
		String pwd = "root";
		try {
			Class.forName(driver);
			conn = DriverManager.getConnection(url,name,pwd);
		} catch (ClassNotFoundException e) {
			System.out.println("找不到驱动");
		}catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return conn;
	}
	
} 
你看看和你的有什么区别、
boolean flag = false;
		Connection con = GetConnect();
		PreparedStatement pstat = null;
		ResultSet rs = null;
		List list = new ArrayList();
		String sql = "select probigimg, prosmallimg from product where probigimg like '%20081/%' and probigimg like '%20081/%'";
		pstat = con.prepareStatement(sql);
		rs = pstat.executeQuery();
		while (rs.next()) {
			Product user = new Product();
			user.setProsmallimg(rs.getString("prosmallimg"));
			user.setProbigimg(rs.getString("probigimg"));
			list.add(user);
		}
		System.out.println(list.size());
		return list;
这个是我测试用的、、你参考一下、吧！ 最好将你的 连接数据库的util类 发出来看看,这么看表面是你的  UserDao 里面做数据库操作的时候报的空指针异常。 没连接上数据库，看看填写的连接URL是否正确 

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