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连接数据库出错处理办法

没学好,又要学jsp了....
1.
安装:SQL Server 2000 Driver for JDBC Service Pack 3
下载安装JDBC SP3
/downloads/details.aspx?familyid=07287B11-0502-461 A-B138-2AA54BFDC03A&displaylang=en
里面的SetUp.exe
按照提示安装可以了.成功后有三个文件要使用:
c:\program files\Microsoft SQL Server 2000 Driver for JDBC\lib\msbase.jar
c:\program files\Microsoft SQL Server 2000 Driver for JDBC\lib\msutil.jar
c:\program files\Microsoft SQL Server 2000 Driver for JDBC\lib\mssqlserver.jar 2.测试代码
新建类文件Connect.java.
package test;
import java.*;
import java.sql.Driver;
public class Connect{
private java.sql.Connection con = null;
private final String url = "jdbc:m icrosoft:sqlserver://";
private final String serverName= "localhost";
private final String port Number = "1433";
private final String databaseName= "DBtest";
private final String userName = "sa";
private final String password = "123456";
// Informs the driver to use server a side-cursor,
// which permits m ore than one active statem ent
// on a connection.
private final String selectMethod = "cursor";
// Constructor
public Connect(){}
private String getConnectionUrl(){
return
url+serverName+":"+portNumber+";databaseName="+databaseName+";select Method="+selectMethod+";";
}
private java.sql.Connection getConnection(){
try{
Class.forNam e("com.microsoft.jdbc.sqlserver.SQLServerDriver");
con =
java.sql.DriverManager.getConnection(getConnectionUrl(),userName,password);
if(con!=null) System.out.println("Connection Successful!");
}catch(Exception e){
e.printStackTrace();
System.out.println("Error Trace in getConnection() : " +
e.getMessage());
}
return con;
}
/*
Display the driver properties, database details
*/
public void displayDbProperties(){
java.sql.DatabaseMetaData dm = null;
java.sql.ResultSet rs = null;
try{
con= this.getConnection();
if(con!=null){
dm = con.getMetaData();
System.out.println("Driver Information");
System.out.println("\t Driver Name: "+ dm.get DriverName());
System.out.println("\t Driver Version: "+ dm.get DriverVersion ());
System.out.println("\nDatabase Information ");
System.out.println("\t Database Name: "+
dm.get DatabaseProductNam e());
System.out.println("\t Database Version: "+
dm.get DatabaseProductVersion());
System.out.println("Avalilable Catalogs ");
rs = dm.getCatalogs();
while(rs.next()){
System.out.println("\tcatalog: "+ rs.getString(1));
}
rs.close();
rs = null;
closeConnection();
}else System.out.println("Error: No active Connection");
}catch(Exception e){
e.printStackTrace();
}
dm=null;
}
private void closeConnection(){
try{
if(con!=null)
con.close();
con=null;
}catch(Exception e){
e.printStackTrace();
}
}
public static void m ain(String[] args) throws Exception
{
Connect m yDbTest = new Connect();
m yDbTest.displayDbProperties();
}
}
代码来源:
/default.aspx?scid=kb;zh-cn;313100 ------------------------------------------
成功后控制台输出:
Connection Successful!
Driver Information
Driver Nam e: SQLServer
Driver Version: 2.2.0040
Database Information
Database Name: Microsoft SQL Server
Database Version: Microsoft SQL Server 2000 - 8.00.760 (Intel X86)
Dec 17 2002 14:22:05
Copyright (c) 1988-2003 Microsoft Corporation
Enterprise Edition on Windows NT 5.2 (Build 3790: )
Avalilable Catalogs
catalog: DBtest
...........
3.问题:
在测试中控制台老输出下面的错误!
找资料找了很久.都说把jdbc安装后的三个jar文件的路径放进环境变量里可以了但我试了不行的!
ng.ClassNotFoundException: com.microsoft.jdbc.sqlserver.SQLServerDriver .........
Error Trace in getConnection() : com.microsoft.jdbc.sqlserver.SQLServerDriver Error: No active Connection
请教了别人才找到办法:
包资源管理器-->包名右键"构建路径"-->配置构建路径-->java构建路径-->库-->添加外部JAR
把那三个JAR选择进去就可以了.
添加后三个JDBC文件就有了.
慢慢学JSP.郁闷......。

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