java getGeneratedKeys(获取自动递增主键)

public boolean save(Emp user) {
try {
Connection conn = DBUtil2.getConnection();
//PreparedStatement ps =
//		conn.prepareStatement(SAVE_SQL, new String[] { "id" });
//应该返回生成的主键，上下两种方式都可
PreparedStatement ps = conn.prepareStatement(SAVE_SQL,PreparedStatement.RETURN_GENERATED_KEYS);
ps.setString(1, user.getName());
ps.setFloat(2, user.getSalary());
ps.setInt(3, user.getAge());
if (ps.executeUpdate() > 0) {
//获取主键
ResultSet rs = ps.getGeneratedKeys();
rs.next();
int i = rs.getInt(1);
user.setId(i);
ps.close();
return true;
}
ps.close();
} catch (SQLException e) {
e.printStackTrace();
} finally {
DBUtil2.closeConnection();
}
return false;
}