如何在JDBC中更新CachedRowSet对象中的行的列？
CachedRowSet是断开连接的行集的基本实现。它连接到数据源，从中读取数据，与数据源断开连接并处理检索到的数据，重新连接到数据源并写入修改。
您可以使用RowSetFactory的createCachedRowSet()方法创建一个CachedRowSet对象。
您可以使用newfactory()RowSetProvider方法的方法创建RowSetFactory对象。
更新行的特定列
CachedRowSet接口的updateXXX()方法允许您更新RowSet对象中特定行的列值。
getXXX()例如，使用相应的方法获取所需的行并更新所需的列，例如，如果您需要在第1列插入整数值，在第2列插入字符串值，则可以使用updateInt()andupdateString()方法，如下所示：
rowSet.updateInt(1, integerValue); rowSet.updateString(2, "stringValue");
修改/更新列值后，使用updateRow()方法将这些更改更新到RowSet。
为了使这些更改反映在数据库中，请使用acceptChanges()方法接受更改。使用此方法，您需要传递与数据库建立连接所使用的连接对象。
示例
假设我们在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 | +----+-------------+--------------+--------------+--------------+-------+----------------+
遵循JDBC程序可将键盘价格降低5000。
import java.sql.Connection;
import java.sql.DriverManager;
import javax.sql.rowset.CachedRowSet;
import javax.sql.rowset.RowSetFactory;
import javax.sql.rowset.RowSetProvider;
public class UpdatingCatchedRowSet {
public static void main(String args[]) throws Exception {
String mysqlUrl = "jdbc:mysql://localhost/sampleDB";
Connection con = DriverManager.getConnection(mysqlUrl, "root", "password");
System.out.println("Connection established......");
con.setAutoCommit(false);
//创建RowSet对象
RowSetFactory factory = RowSetProvider.newFactory();
CachedRowSet rowSet = factory.createCachedRowSet();
//设置查询/命令
rowSet.setCommand("select * from ProductSales");
//执行命令
rowSet.execute(con);
System.out.println("Contents of the table: ");
while(rowSet.next()) {
if(rowSet.getString("ProductName").equals("Key-Board")) {
rowSet.updateInt("Price", rowSet.getInt("Price")-5000 );
rowSet.updateRow();
}
}
rowSet.acceptChanges();
rowSet.beforeFirst();
System.out.println("Contents of the table after updating the row");
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("");
}
}
}输出结果
Connection established...... Connection established...... Contents of the table: Contents of the table after updating the row ID: 1, Product Name: Key-Board, Customer Name: Raja, Dispatch Date: 2019-09-01, Delivery Time: 05:30:00Price: 2000, 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