JDBC

获取插入主键

public int register(String username, String password, String email) throws Exception {
    Connection connection = DbUtil.getCon();
    String sql="insert into  user (username,password,email) values (?,?,?) ";
    PreparedStatement ps = connection.prepareStatement(sql, Statement.RETURN_GENERATED_KEYS);
    ps.setString(1, username);
    ps.setString(2, password);
    ps.setString(3, email);

    ps.executeUpdate();
    ResultSet rs = ps.getGeneratedKeys();
    //返回的结果集中包含主键,注意：主键还可以是UUID,
    //复合主键等,所以这里不是直接返回一个整型
    int uid = -1;
    if(rs.next()){
        uid = rs.getInt(1);
    }
    return uid;

}