String sql = "INSERT INTO users (username,password,email) VALUES (?,?,?);"; PreparedStatement pstmt = (PreparedStatement) conn.prepareStatement(sql,Statement.RETURN_GENERATED_KEYS);//传入参数：Statement.RETURN_GENERATED_KEYS pstmt.setString(1, user.getUsername()); pstmt.setString(2, user.getPassword()); pstmt.setString(3, user.getEmail()); pstmt.executeUpdate();//执行sql                                                                             int autoInckey = -1; ResultSet rs = pstmt.getGeneratedKeys(); //获取结果   if (rs.next()) { 　　autoIncKey = rs.getInt(1);//取得ID } else { 　　// throw an exception from here }

SELECT MAX(id) FROM table

SELECT LAST_INSERT_ID() 或者 SELECT @@INDENTITY