java select @@IDENTITY 取值为题

[星痕2016]

Connection conn = connPool.getConnection();
try {
String sql = "insert into yy_buyGood (companyBID,buyDate,realDate,flag)"+
" values(?,?,?,?)";
PreparedStatement stmt = conn.prepareStatement(sql);
stmt.setInt(1,companyBID);
stmt.setDate(2,buyDate);
stmt.setTimestamp(3,realDate);
stmt.setString(4,flag);
stmt.executeUpdate();
sql = "select @@IDENTITY as 'justID'";
stmt = conn.prepareStatement(sql);
ResultSet rs = stmt.executeQuery();
if(rs.next()){
buyGoodID = rs.getInt("justID");

System.out.print(">>>>>>"+buyGoodID);//调试，显示为0，奇怪啊！
}
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}


这个为什么取不到新插入的int值

[spring_0534]

sql = "select @@IDENTITY as 'justID'";
不需要表名吗？
关注ing...

[hy0231]

事务还没提交，你就去查询，肯定查不处出来了。

[wcsandoyq]

select @@IDENTITY无需表名,因为它得到的是上一条sql语句执行后的自动增长列的值
应该直接将其放在要执行的sql之后, sql = "select @@IDENTITY as 'justID'";是多余的