Java如何检查光标是否在第一行？
迭代可滚动的结果集时，可以检查您是否位于结果集的开头。该isBeforFirst()方法检查位置是否在开头，如果是，则此方法将返回true，否则将返回false。
package org.nhooo.example.jdbc;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class ScrollableIsBeforeFirstExample {
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.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_READ_ONLY);
String sql = "SELECT code, name, price FROM products";
ResultSet resultSet = statement.executeQuery(sql);
//使用isBeforeFirst()方法，我们可以检查是否在
//结果集的开始。
if (resultSet.isBeforeFirst()) {
System.out.println("You are at the beginning of the " +
"result set.");
}
} 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>