我的SQL数据库为什么连接不上呢？

我写了个java程序，连接 SQL Server数据库。可老是有异常，我又看不懂，哪位大虾能给点意见啊！小弟谢谢了！！

import java.sql.*;


public class JDBCExample{
    public static void main(String args[]){
        try{            
            Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver").newInstance();
            Connection conn = DriverManager.getConnection("jdbc:microsoft:sqlserver://localhost:1433; DatabaseName=master","sa","");
            Statement stmt = conn.createStatement();
            ResultSet rs = stmt.executeQuery("select * from student");
            while(rs.next()){
                System.out.print("学号: " + rs.getInt(1));
                System.out.print("\t姓名: " + rs.getString(2));
                System.out.print("\t性别: " + rs.getInt(3));   
                System.out.println("\t年龄: " + rs.getString(4));
            }
            rs.close();
            stmt.close();
            conn.close();
        }catch(Exception e){
            e.printStackTrace();
        }
    }
}


下面的是异常信息：
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:582)
    at java.sql.DriverManager.getConnection(DriverManager.java:185)
    at test.JDBCExample.main(JDBCExample.java:9)