如何在 JDBC 中将数据插入 CachedRowSet?解释一下?
jdbcjava 8object oriented programmingprogramming
CachedRowSet 是不连续行集的基本实现。它连接到数据源，从中读取数据，断开与数据源的连接并处理检索到的数据，重新连接到数据源并写入修改。
创建 CachedRowSet
您可以使用 RowSetFactory 的 createCachedRowSet() 方法创建一个 Cached RowSet 对象。
您可以使用 RowSetProvider 方法的 newfactory() 方法创建一个 RowSetFactory 对象。
使用上述方法创建一个 CachedRowSet 对象，如下所示 −
//创建 RowSet 对象 RowSetFactory factory = RowSetProvider.newFactory(); CachedRowSet rowSet = factory.createCachedRowSet();
连接数据源
创建 RowSet 对象后，需要将其连接到所需的 DataSource。
您可以通过设置用户名、密码、URL 以及数据源名称(减号)等属性的值来连接到 DataSource。
//设置 URL
String mysqlUrl = "jdbc:mysql://localhost/SampleDB";
rowSet.setUrl(mysqlUrl);
//设置用户名
rowSet.setUsername("root");
//设置密码
rowSet.setPassword("password");
准备并执行命令语句
缓存的行集具有一个 command 属性，您可以将查询传递给该属性。使用 setCommand() 方法将所需查询设置为此属性。
rowSet.setCommand("select * from ProductSales");
您可以使用 execute() 方法执行 RowSet 对象所包含的查询。
rowSet.execute();
在 CachedRowSet 中插入一行
CachedRowSet 接口的 moveToInsertRow() 方法会将光标导航到需要插入下一条记录的位置。
因此，使用此方法将光标移动到适当的位置以插入行。
CachedRowSet 接口的 updateXXX() 方法允许您在 RowSet 对象中插入/更新值。
使用这些方法向新行添加值，例如，如果您需要在第一列插入一个整数值，在第二列插入一个字符串值，您可以使用 updateInt() 和 updateString() 方法作为 − 来实现。
rowSet.updateInt(1, integerValue); rowSet.updateString(2, "stringValue");
insertRow() 方法将行插入到 CachedRowSet 和表中。
因此，使用此方法将上面创建的行插入到 CachedRowSet 对象和表中。
示例
假设数据库中有一个名为 ProductSales 的表，其内容如下 −
+----+-------------+--------------+--------------+--------------+-------+----------------+ | ID | ProductName | CustomerName | DispatchDate | DeliveryTime | Price |Location | +----+-------------+--------------+--------------+--------------+-------+----------------+ | 1 | Key-Board | Raja | 2019-09-01 | 05:30:00 | 7000 |Hyderabad | | 2 | Earphones | Roja | 2019-05-01 | 05:30:00 | 2000 |Vishakhapatnam | | 3 | Mouse | Puja | 2019-03-01 | 05:29:59 | 3000 |Vijayawada | | 4 | Mobile | Vanaja | 2019-03-01 | 04:40:52 | 9000 |Chennai | | 5 | Headset | Jalaja | 2019-04-06 | 18:38:59 | 6000 |Goa | +----+-------------+--------------+--------------+--------------+-------+----------------+
以下示例将上述表的内容检索到 CachedRowSet 对象中，并在其中插入一条新记录。
import java.sql.Date;
import java.sql.DriverManager;
import java.sql.Time;
import javax.sql.rowset.CachedRowSet;
import javax.sql.rowset.RowSetFactory;
import javax.sql.rowset.RowSetProvider;
public class CachedRowSetExample {
public static void main(String args[]) throws Exception {
//注册驱动程序
DriverManager.registerDriver(new com.mysql.jdbc.Driver());
//创建 RowSet 对象
RowSetFactory factory = RowSetProvider.newFactory();
CachedRowSet rowSet = factory.createCachedRowSet();
//设置 URL
String mysqlUrl = "jdbc:mysql://localhost/SampleDB";
rowSet.setUrl(mysqlUrl);
//设置用户名
rowSet.setUsername("root");
//设置密码
rowSet.setPassword("password");
//设置查询/命令
rowSet.setCommand("select * from ProductSales");
rowSet.execute();
System.out.println("Contents of the row set");
while(rowSet.next()) {
System.out.print("ID: "+rowSet.getInt("ID")+", ");
System.out.print("Product Name: "+rowSet.getString("ProductName")+", ");
System.out.print("Customer Name: "+rowSet.getString("CustomerName")+", ");
System.out.print("Dispatch Date: "+rowSet.getDate("DispatchDate")+", ");
System.out.print("Delivery Time: "+rowSet.getTime("DeliveryTime"));
System.out.print("Price: "+rowSet.getString("Price")+", ");
System.out.print("Location: "+rowSet.getString("Location"));
System.out.println("");
}
//将数据插入到 RowSet 对象中
rowSet.moveToInsertRow();
rowSet.updateInt(1, 6);
rowSet.updateString(2, "Laptop");
rowSet.updateString(3, "Jagadeesh");
rowSet.updateDate(4, new Date(1551899399000L));
rowSet.updateTime(5, new Time(1551899399000L));
rowSet.updateInt(6, 50000);
rowSet.updateString(7, "Mumbai");
rowSet.insertRow();
rowSet.moveToCurrentRow();
System.out.println("");
System.out.println("Contents of the row set after inserting a new row: ");
System.out.println("");
rowSet.beforeFirst();
while(rowSet.next()) {
System.out.print("ID: "+rowSet.getInt("ID")+", ");
System.out.print("Product Name: "+rowSet.getString("ProductName")+", ");
System.out.print("Customer Name: "+rowSet.getString("CustomerName")+", ");
System.out.print("Dispatch Date: "+rowSet.getDate("DispatchDate")+", ");
System.out.print("Delivery Time: "+rowSet.getTime("DeliveryTime"));
System.out.print("Price: "+rowSet.getString("Price")+", ");
System.out.print("Location: "+rowSet.getString("Location"));
System.out.println("");
}
}
}
输出
Contents of the row set ID: 1, Product Name: Key-Board, Customer Name: Raja, Dispatch Date: 2019-09-01, Delivery Time: 05:30:00Price: 7000, Location: Hyderabad ID: 2, Product Name: Earphones, Customer Name: Roja, Dispatch Date: 2019-05-01, Delivery Time: 05:30:00Price: 2000, Location: Vishakhapatnam ID: 3, Product Name: Mouse, Customer Name: Puja, Dispatch Date: 2019-03-01, Delivery Time: 05:29:59Price: 3000, Location: Vijayawada ID: 4, Product Name: Mobile, Customer Name: Vanaja, Dispatch Date: 2019-03-01, Delivery Time: 04:40:52Price: 9000, Location: Chennai ID: 5, Product Name: Headset, Customer Name: Jalaja, Dispatch Date: 2019-04-06, Delivery Time: 18:38:59Price: 6000, Location: Goa Contents of the table after inserting a new row: ID: 1, Product Name: Key-Board, Customer Name: Raja, Dispatch Date: 2019-09-01, Delivery Time: 05:30:00Price: 7000, Location: Hyderabad ID: 2, Product Name: Earphones, Customer Name: Roja, Dispatch Date: 2019-05-01, Delivery Time: 05:30:00Price: 2000, Location: Vishakhapatnam ID: 3, Product Name: Mouse, Customer Name: Puja, Dispatch Date: 2019-03-01, Delivery Time: 05:29:59Price: 3000, Location: Vijayawada ID: 4, Product Name: Mobile, Customer Name: Vanaja, Dispatch Date: 2019-03-01, Delivery Time: 04:40:52Price: 9000, Location: Chennai ID: 5, Product Name: Headset, Customer Name: Jalaja, Dispatch Date: 2019-04-06, Delivery Time: 18:38:59Price: 6000, Location: Goa ID: 6, Product Name: Laptop, Customer Name: Jagadeesh, Dispatch Date: 1970-01-19, Delivery Time: 04:34:59Price: 50000, Location: Mumbai
