求助，sql server 2008连不上数据库
在同学的电脑上又可以运行，求解package com.yxq.dao;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
public class DB {
private String className;
private String url;
private String username;
private String password;
private Connection con;
private PreparedStatement pstm;
public DB(){
className="net.sourceforge.jtds.jdbc.Driver";
url="jdbc:jtds:sqlserver://localhost:1433/db_sp";
username="sa";
password="jiaqizhi";
try{
Class.forName(className);
}catch(ClassNotFoundException e){
System.out.println("加载数据库驱动程序失败！");
e.printStackTrace();
}
}
public void getCon(){
try {
con=DriverManager.getConnection(url,username,password);
} catch (SQLException e) {
System.out.println("获取数据库连接失败！");
e.printStackTrace();
}
}
public void doPstm(String sql,Object[] params){
if(sql!=null&&!sql.equals("")){
System.out.println(sql);
getCon();
try {
pstm=con.prepareStatement(sql,ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
if(params==null){
params=new Object[0];
}
for(int i=0;i<params.length;i++){
pstm.setObject(i+1,params[i]);
}
pstm.execute();
} catch (SQLException e) {
System.out.println("调用DB类中doPstm方法时出错！");
e.printStackTrace();
}
}
}
public ResultSet getRs(){
try {
return pstm.getResultSet();
} catch (SQLException e) {
System.out.println("DB类中的getRs()方法出错！");
e.printStackTrace();
return null;
}
}
public int getUpdate(){
try {
return pstm.getUpdateCount();
} catch (SQLException e) {
e.printStackTrace();
return -1;
}
}
public void closed(){
try{
if(pstm!=null)
pstm.close();
}catch(Exception e){
System.out.println("关闭pstm对象失败！");
}
try{
if(con!=null)
con.close();
}catch(Exception e){
System.out.println("关闭con对象失败！");
}
}
}
源代码如上所述
报错：
select * from tb_class
获取数据库连接失败！
java.sql.SQLException: Network error IOException: Connection refused: connect
at net.sourceforge.jtds.jdbc.ConnectionJDBC2.<init>(ConnectionJDBC2.java:385)
at net.sourceforge.jtds.jdbc.ConnectionJDBC3.<init>(ConnectionJDBC3.java:50)
at net.sourceforge.jtds.jdbc.Driver.connect(Driver.java:182)
at java.sql.DriverManager.getConnection(DriverManager.java:620)
at java.sql.DriverManager.getConnection(DriverManager.java:200)
at com.yxq.dao.DB.getCon(DB.java:31)
at com.yxq.dao.DB.doPstm(DB.java:41)
at com.yxq.dao.OpDB.OpClassListShow(OpDB.java:27)
at com.yxq.action.IndexAction.execute(IndexAction.java:29)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:419)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:224)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1194)
at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:690)
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:233)
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:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:263)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:584)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Thread.java:717)
Caused by: java.net.ConnectException: Connection refused: connect
at java.net.DualStackPlainSocketImpl.connect0(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:69)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:316)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:177)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:164)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:154)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:354)
at java.net.Socket.connect(Socket.java:574)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:617)
at net.sourceforge.jtds.jdbc.SharedSocket.createSocketForJDBC3(SharedSocket.java:304)
at net.sourceforge.jtds.jdbc.SharedSocket.<init>(SharedSocket.java:255)
at net.sourceforge.jtds.jdbc.ConnectionJDBC2.<init>(ConnectionJDBC2.java:310)
... 26 more
2013-4-4 12:55:06 org.apache.catalina.core.StandardWrapperValve invoke
严重: Servlet.service() for servlet action threw exception
java.lang.NullPointerException
at com.yxq.dao.DB.doPstm(DB.java:43)
at com.yxq.dao.OpDB.OpClassListShow(OpDB.java:27)
at com.yxq.action.IndexAction.execute(IndexAction.java:29)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:419)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:224)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1194)
at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:690)
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:233)
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:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:263)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:584)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Thread.java:717) --------------------编程问答-------------------- Servlet服务没开吗？ --------------------编程问答--------------------
Sever，打错了 --------------------编程问答-------------------- 已经开了，是管理服务那个么？ --------------------编程问答-------------------- 程序应该没有错，一般连接数据库要注意两点：1、开启数据库服务器；2、在lib文件夹下添加数据库驱动.jar包，看一下你的这两项有问题没。
补充：Java , Java EE
