我是个新手,写了一个连接数据库的类,但就是一直出错,请帮帮忙
本拉灯 2003-08-19 11:35:20 public class dataconn
{ private Connection conn;
private ResultSet rs;
private String dbs;
public dataconn()
{
}
public Connection setConnection(String db)
{
dbs="jdbc:odbc:"+db;
try{
Class.forName("sum.jdbc.odbc.JdbcOdbcDriver");
conn=DriverManager.getConnection(dbs);
}
catch(Exception e)
{
System.out.print(e.toString());
}
//return conn;
}
public ResultSet getQuery(String sqls)
{
try
{
Statement statement=conn.createStatement();
rs=statement.executeQuery(sqls);
}
catch(Exception e)
{
System.out.println(e.toString());
}
return rs;
}
public void SetModify(String sqls)
{
try
{
Statement statement=conn.createStatement();
statement.executeUpdate(sqls);
}
catch(Exception e)
{
System.out.println(e.toString());
}
}
}
下面是引用上面这个类
int i=0;
dataconn d;
ResultSet rs;
Connection conn;
d=new dataconn();
conn=d.setConnection("webdata");
if(conn.isClosed())
out.println("数据库已经关闭了!<br>");
else
out.println("数据库正在打开中!<br>");
conn.close();
if(conn.isClosed())
out.println("数据库已经关闭了!");
else
out.println("数据库正在打开中!");
他就一直出现下面这个(resin服务器)
java.lang.NullPointerException
at _fu__jsp._jspService(/cs/fu.jsp:16)
at com.caucho.jsp.JavaPage.service(JavaPage.java:75)
at com.caucho.jsp.Page.subservice(Page.java:485)
at com.caucho.server.http.FilterChainPage.doFilter(FilterChainPage.java:182)
at com.caucho.server.http.Invocation.service(Invocation.java:312)
at com.caucho.server.http.CacheInvocation.service(CacheInvocation.java:135)
at com.caucho.server.http.HttpRequest.handleRequest(HttpRequest.java:221)
at com.caucho.server.http.HttpRequest.handleConnection(HttpRequest.java:163)
at com.caucho.server.TcpConnection.run(TcpConnection.java:137)
at java.lang.Thread.run(Thread.java:536)
请说说这是什么问题,还有怎么解决,,,