java连接数据库的问题
我的系统是xp   sp2版本的,用JBuilder2005连接数据库时出现以下异常,该如何处理(声明:连接程序有,数据库是   sql   server2000   Developer   Edition   版本   )  
java.sql.SQLException:   [Microsoft][SQLServer   2000   Driver   for   JDBC]Error   establishing   socket.   
 	at   com.microsoft.jdbc.base.BaseExceptions.createException(Unknown   Source)   
 	at   com.microsoft.jdbc.base.BaseExceptions.getException(Unknown   Source)   
 	at   com.microsoft.jdbc.base.BaseExceptions.getException(Unknown   Source)   
 	at   com.microsoft.jdbc.sqlserver.tds.TDSConnection. <init> (Unknown   Source)   
 	at   com.microsoft.jdbc.sqlserver.SQLServerImplConnection.open(Unknown   Source)   
 	at   com.microsoft.jdbc.base.BaseConnection.getNewImplConnection(Unknown   Source)   
 	at   com.microsoft.jdbc.base.BaseConnection.open(Unknown   Source)   
 	at   com.microsoft.jdbc.base.BaseDriver.connect(Unknown   Source)   
 	at   java.sql.DriverManager.getConnection(DriverManager.java:512)   
 	at   java.sql.DriverManager.getConnection(DriverManager.java:171)   
 	at   test.DataBase.getResultset(DataBase.java:29)   
 	at   test.Frame1.jButton4_actionPerformed(Frame1.java:133)   
 	at   test.Frame1_jButton4_actionAdapter.actionPerformed(Frame1.java:156)   
 	at   javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1786)   
 	at   javax.swing.AbstractButton$ForwardActionEvents.actionPerformed(AbstractButton.java:1839)   
 	at   javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:420)   
 	at   javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:258)   
 	at   javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:245)   
 	at   java.awt.Component.processMouseEvent(Component.java:5100)   
 	at   java.awt.Component.processEvent(Component.java:4897)   
 	at   java.awt.Container.processEvent(Container.java:1569)   
 	at   java.awt.Component.dispatchEventImpl(Component.java:3615)   
 	at   java.awt.Container.dispatchEventImpl(Container.java:1627)   
 	at   java.awt.Component.dispatchEvent(Component.java:3477)   
 	at   java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:3483)   
 	at   java.awt.LightweightDispatcher.processMouseEvent(Container.java:3198)   
 	at   java.awt.LightweightDispatcher.dispatchEvent(Container.java:3128)   
 	at   java.awt.Container.dispatchEventImpl(Container.java:1613)   
 	at   java.awt.Window.dispatchEventImpl(Window.java:1606)   
 	at   java.awt.Component.dispatchEvent(Component.java:3477)   
 	at   java.awt.EventQueue.dispatchEvent(EventQueue.java:456)   
 	at   java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:201)   
 	at   java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)   
 	at   java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:145)   
 	at   java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:137)   
 	at   java.awt.EventDispatchThread.run(EventDispatchThread.java:100)    
java.lang.NullPointerException    	at   test.Frame1.jButton4_actionPerformed(Frame1.java:135)   
 	at   test.Frame1_jButton4_actionAdapter.actionPerformed(Frame1.java:156)   
 	at   javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1786)   
 	at   javax.swing.AbstractButton$ForwardActionEvents.actionPerformed(AbstractButton.java:1839)