在mssql下如何获得刚插入字段的值(该字段是自增)?

今天上网查资料写了一个在mssql获得刚插入字段的值(该字段是自增的),但返回的老是零,为什么,请大家帮忙看一下?
数据库表是 message(int id,varchar name) 其中id是自增的
代码如下:
GetIdentity.java

 1package com.study.dbo;
 2
 3import java.sql.Connection;
 4import java.sql.DriverManager;
 5import java.sql.PreparedStatement;
 6import java.sql.ResultSet;
 7import java.sql.SQLException;
 8import java.sql.Statement;
 9
10public class GetIdentity {
11
12    public static void main(String[] args) {
13        
14        Connection conn=null;
15        try {
16            Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
17            conn=DriverManager.getConnection("jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=demo;SelectMethod=Cursor;User=sa;Password=sa");
18            conn.setAutoCommit(false);
19            String insert="insert into message values('wuguoming2010')";
20            PreparedStatement prestmt=conn.prepareStatement(insert);
21            prestmt.execute();
22            String sql="select SCOPE_IDENTITY()";
23//            String sql="select @@identity";
24            prestmt=conn.prepareStatement(sql);
25            ResultSet rs=prestmt.executeQuery();
26            long identity=0;
27            while (rs.next()) {
28                System.out.println(rs.getLong(1));
29                identity=rs.getLong(1);
30            }
31            conn.commit();
32            System.out.println(identity);
33        } catch (ClassNotFoundException e) {
34            // TODO Auto-generated catch block
35            e.printStackTrace();
36        }
37        catch (SQLException sqle) {
38            // TODO Auto-generated catch block
39            sqle.printStackTrace();
40        }
41    }
42}

打印出来的老是零?为什么?请大家看一下,帮个忙,谢谢!!