如何在Java中使用LocalDateTime類在表中設定本地日期/時間?
Java8的java.time包提供了一個名為LocalDateTime的類,用於獲取本地日期和時間的當前值。除了日期和時間值之外,您還可以獲取其他日期和時間欄位,例如一年中的某一天、一週中的某一天和一年中的某一週。
將本地時間設定為列
要將本地日期和時間值設定為表中的列:
- 獲取LocalDateTime物件 - 您可以透過呼叫靜態方法now()來獲取LocalDateTime物件,如下所示:
//Getting the LocalDateTime object LocalDateTime localDateTime = LocalDateTime.now();
- 從上面獲得的LocalDateTime中獲取LocalDate和LocalTime物件,如下所示:
LocalDate localDate = localDateTime.toLocalDate(); LocalTime localTime = localDateTime.toLocalTime()
- 現在,將LocalDate和LocalTime物件分別傳遞到java.sql.Date和java.sql.Time類的valueOf()方法,如下所示:
java.sql.Date date = java.sql.Date.valueOf(localDate); java.sql.Time time = java.sql.Time.valueOf(localTime);
示例
讓我們使用CREATE語句在MySQL資料庫中建立一個名為dispatches的表,如下所示:
CREATE TABLE dispatches( ProductName VARCHAR(255), CustomerName VARCHAR(255), DispatchDate date, DeliveryTime time, Price INT, Location VARCHAR(255) );
現在,我們將使用INSERT語句在dispatches表中插入5條記錄:
insert into dispatches values('Key-Board', 'Raja', DATE('2019-09-01'), TIME('11:00:00'), 7000, 'Hyderabad');
insert into dispatches values('Earphones', 'Roja', DATE('2019-05-01'), TIME('11:00:00'), 2000, 'Vishakhapatnam');
insert into dispatches values('Mouse', 'Puja', DATE('2019-03-01'), TIME('10:59:59'), 3000, 'Vijayawada');
insert into dispatches values('Mobile', 'Vanaja', DATE('2019-03-01'), TIME('10:10:52'), 9000, 'Chennai');
insert into dispatches values('Headset', 'Jalaja', DATE('2019-04-06'), TIME('11:08:59'), 6000, 'Goa');以下JDBC程式透過傳遞所需的值將新記錄插入到dispatches表中。在這裡,我們獲取當前本地日期和時間值,並將它們作為表中日期和時間列的值插入。
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.time.LocalDateTime;
public class settingLocatDate {
public static void main(String args[]) throws SQLException {
//Registering the Driver
DriverManager.registerDriver(new com.mysql.jdbc.Driver());
//Getting the connection
String mysqlUrl = "jdbc:mysql:///mydatabase";
Connection con = DriverManager.getConnection(mysqlUrl, "root", "password");
System.out.println("Connection established......");
//Getting the LocalDateTime object
LocalDateTime localDateTime = LocalDateTime.now();
System.out.println(localDateTime.toString());
//Converting date and time values from local to SQL
java.sql.Date date = java.sql.Date.valueOf(localDateTime.toLocalDate());
java.sql.Time time = java.sql.Time.valueOf(localDateTime.toLocalTime());
//Creating a Prepared Statement
String query = "INSERT INTO Dispatches VALUES (?, ?, ?, ?, ?, ?)";
PreparedStatement pstmt = con.prepareStatement(query);
pstmt.setString(1, "Watch");
pstmt.setString(2, "Rajan");
pstmt.setDate(3, date);
pstmt.setObject(4, time);
pstmt.setInt(5, 4000);
pstmt.setString(6, "Chennai");
pstmt.execute();
System.out.println("Rows inserted ....");
//Retrieving values
Statement stmt = con.createStatement();
ResultSet rs = stmt.executeQuery("select * from dispatches");
while(rs.next()) {
System.out.println("Product Name: "+rs.getString("ProductName"));
System.out.println("Customer Name: "+rs.getString("CustomerName"));
System.out.println("Date Of Dispatch: "+rs.getDate("DispatchDate"));
System.out.println("Delivery Time: "+rs.getTime("DeliveryTime"));
System.out.println("Location: "+rs.getString("Location"));
System.out.println();
}
}
}輸出
Connection established...... 2019-05-14T15:48:42.457 Rows inserted .... Product Name: Key-Board Customer Name: Raja Date Of Dispatch: 2019-09-01 Delivery Time: 11:00:00 Location: Hyderabad Product Name: Earphones Customer Name: Roja Date Of Dispatch: 2019-05-01 Delivery Time: 11:00:00 Location: Vishakhapatnam Product Name: Mouse Customer Name: Puja Date Of Dispatch: 2019-03-01 Delivery Time: 10:59:59 Location: Vijayawada Product Name: Mobile Customer Name: Vanaja Date Of Dispatch: 2019-03-01 Delivery Time: 10:10:52 Location: Chennai Product Name: Headset Customer Name: Jalaja Date Of Dispatch: 2019-04-06 Delivery Time: 11:08:59 Location: Goa Product Name: Watch Customer Name: Rajan Date Of Dispatch: 2019-05-14 Delivery Time: 15:48:42 Location: Chennai
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