如何使用 Java 中的 LocalDateTime 类在表中设置本地日期/时间?
javaobject oriented programmingprogramming
Java8 的 java.time 包提供了一个名为 LocalDateTime 的类，用于获取本地日期和时间的当前值。除了日期和时间值之外，您还可以使用它来获取其他日期和时间字段，例如一年中的某天、一周中的某天和一年中的某周。
将本地时间设置为列
将本地日期和时间值设置为表中的列 −
- 获取 LocalDateTime 对象 −您可以通过调用静态方法 now() 以 − 的形式获取 LocalDateTime 对象
//获取 LocalDateTime 对象 LocalDateTime localDateTime = LocalDateTime.now();
- 从上面获得的 LocalDateTime 中获取 LocalDate 和 LocalTime 对象以 − 的形式
LocalDate localDate = localDateTime.toLocalDate(); LocalTime localTime = localDateTime.toLocalTime()
- 现在，将 LocalDate 和 LocalTime 对象分别作为− 传递给 java.sql.Date 和 java.sql.Time 类的 valueOf() 方法
java.sql.Date date = java.sql.Date.valueOf(localDate); java.sql.Time time = java.sql.Time.valueOf(localTime);
示例
让我们使用 CREATE 语句在 MySQL 数据库中创建一个名为 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) );
现在，我们将使用 INSERT 语句 − 在 dispatches 表中插入 5 条记录
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 程序通过传递所需值将新记录插入 dispatches 表中。在这里，我们获取当前本地日期和时间值，并将它们作为表的日期和时间列的值插入。
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 {
//注册驱动程序
DriverManager.registerDriver(new com.mysql.jdbc.Driver());
//获取连接
String mysqlUrl = "jdbc:mysql://localhost/mydatabase";
Connection con = DriverManager.getConnection(mysqlUrl, "root", "password");
System.out.println("Connection established......");
//获取 LocalDateTime 对象
LocalDateTime localDateTime = LocalDateTime.now();
System.out.println(localDateTime.toString());
//将日期和时间值从本地转换为 SQL
java.sql.Date date = java.sql.Date.valueOf(localDateTime.toLocalDate());
java.sql.Time time = java.sql.Time.valueOf(localDateTime.toLocalTime());
//创建准备好的语句
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 ....");
//检索值
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();
}
}
}
输出
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
