java插入数据后返回id

可以使用Statement.RETURN_GENERATED_KEYS选项来获取插入数据后的自增主键值。

示例代码：

String sql = "INSERT INTO user(name, age) VALUES('John', 25)";
try (Connection conn = DriverManager.getConnection(url, username, password);
     PreparedStatement pstmt = conn.prepareStatement(sql, Statement.RETURN_GENERATED_KEYS)) {
    int affectedRows = pstmt.executeUpdate();
    if (affectedRows == 0) {
        throw new SQLException("Inserting user failed, no rows affected.");
    }
    try (ResultSet generatedKeys = pstmt.getGeneratedKeys()) {
        if (generatedKeys.next()) {
            int id = generatedKeys.getInt(1);
            System.out.println("Inserted user ID: " + id);
        } else {
            throw new SQLException("Inserting user failed, no ID obtained.");
        }
    }
} catch (SQLException e) {
    e.printStackTrace();
}

在上述示例中，使用Statement.RETURN_GENERATED_KEYS选项创建了PreparedStatement对象，并在执行插入语句后通过getGeneratedKeys()方法获取自增主键值。如果获取成功，则输出插入数据的ID值。