Java我如何知道表列的值是否是自动递增的？
该ResultSetMetaData.isAutoIncrement()方法可以告诉我们是否自动对列值进行编号。true当列是自动递增的列时，此方法返回，否则返回false。请参见下面的示例，在该示例中我们检查第一列（id）是否为自动增量列。
package org.nhooo.example.jdbc;
import java.sql.*;
public class IsAutoIncrementExample {
private static final String URL = "jdbc:mysql://localhost/nhooo";
private static final String USERNAME = "root";
private static final String PASSWORD = "";
public static void main(String[] args) {
try (Connection connection =
DriverManager.getConnection(URL, USERNAME, PASSWORD)) {
Statement statement = connection.createStatement();
ResultSet resultSet = statement.executeQuery(
"SELECT id, username, order_date FROM orders");
//ResultSetMetaData是所有元数据相关的地方
//存储结果集的信息。
ResultSetMetaData metadata = resultSet.getMetaData();
if (metadata.isAutoIncrement(1)) {
System.out.println("Column `id` is an auto-increment column.");
}
} catch (SQLException e) {
e.printStackTrace();
}
}
}Maven依赖
<!-- https://search.maven.org/remotecontent?filepath=mysql/mysql-connector-java/8.0.17/mysql-connector-java-8.0.17.jar -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.17</version>
</dependency>