簡單分頁查詢實現原理

如何實現分類查詢

package jdbc;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class QueryCurrentPage {

	private static String url = "jdbc:mysql://127.0.0.1:3306/study?characterEncoding=UTF-8";
	private static String userName = "root";
	private static String passWord = "root";

	public static void main(String[] args) {

		queryByPage(2, 4);
	}

/**
 * 分頁查詢
 * @param currentPage	當前頁
 * @param pageSize		每頁將顯示的數據量
 */
	public static void queryByPage(int currentPage, int pageSize) {

		try {
			Class.forName("com.mysql.jdbc.Driver");
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}

		ResultSet resultSet = null;
		// 將資源聲明在try()中,當語句結束,資源將被關閉
		try (Connection connection = DriverManager.getConnection(url, userName, passWord);
				PreparedStatement preparedStatement = connection
						.prepareStatement("select * from employee limit ?,?;");) {

			preparedStatement.setInt(1, (currentPage - 1) * pageSize);
			preparedStatement.setInt(2, pageSize);

			resultSet = preparedStatement.executeQuery();

			while (resultSet.next()) {
				System.out.print(resultSet.getInt("id"));
				System.out.print(resultSet.getString("name"));
				System.out.print(resultSet.getString("email"));
				System.out.println(resultSet.getInt("salary"));
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}
	}
}

完~