如何使用JDBC程序更新ResultSet的内容？
要更新ResultSet的内容，您需要通过传递ResultSet类型的可更新来创建一条语句，如下所示：
//创建一个Statement对象Statement stmt = con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_UPDATABLE);
就像getXXX()和setXXX()方法一样，ResultSet接口也提供了更新结果集中行内容的方法updateXXX()。
这些方法接受表示要更新的行的索引的整数值，或表示列标签的String值。
请注意，如果您需要更新ResultSet的内容，则该表应具有主键。
示例
假设我们有一个名为Employees的表，具有5条记录，如下所示：
+----+---------+--------+----------------+| Id | Name | Salary | Location |
+----+---------+--------+----------------+
| 1 | Amit | 3000 | Hyderabad |
| 2 | Kalyan | 4000 | Vishakhapatnam |
| 3 | Renuka | 6000 | Delhi |
| 4 | Archana | 9000 | Mumbai |
| 5 | Sumith | 11000 | Hyderabad |
+----+---------+--------+----------------+
下面的示例演示如何更新结果集的内容：
import java.sql.*;public class ResultSetExample {
public static void main(String[] args) throws Exception {
//注册驱动程序
DriverManager.registerDriver(new com.mysql.jdbc.Driver());
//获得连接
String mysqlUrl = "jdbc:mysql://localhost/TestDB";
Connection con = DriverManager.getConnection(mysqlUrl, "root", "password");
System.out.println("Connection established......");
//创建一个Statement对象
Statement stmt = con.createStatement(
ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
//检索数据
ResultSet rs = stmt.executeQuery("select * from Employees");
//打印表的内容
System.out.println("Contents of the table: ");
printRs(rs);
//的起点
rs.beforeFirst();
//每位员工的薪水提高5000-
while(rs.next()){
//通过列名检索
int newSal = rs.getInt("Salary") + 5000;
rs.updateInt( "Salary", newSal );
rs.updateRow();
}
System.out.println("Contents of the ResultSet after increasing salaries");
printRs(rs);
//首先将位置设置为第二条记录
rs.beforeFirst();
rs.absolute(2);
System.out.println("Record we need to delete: ");
System.out.print("ID: " + rs.getInt("id"));
System.out.print(", Salary: " + rs.getInt("Salary"));
System.out.print(", Name: " + rs.getString("Name"));
System.out.println(", Location: " + rs.getString("Location"));
System.out.println(" ");
//删除行
rs.deleteRow();
System.out.println("Contents of the ResultSet after deleting one records...");
printRs(rs);
System.out.println("Goodbye!");
}
public static void printRs(ResultSet rs) throws SQLException{
//确保我们从第一行开始
rs.beforeFirst();
while(rs.next()){
System.out.print("ID: " + rs.getInt("id"));
System.out.print(", Salary: " + rs.getInt("Salary"));
System.out.print(", Name: " + rs.getString("Name"));
System.out.println(", Location: " + rs.getString("Location"));
}
System.out.println();
}
}
输出结果
Connection established......Contents of the table:
ID: 1, Salary: 3000, Name: Amit, Location: Hyderabad
ID: 2, Salary: 4000, Name: Kalyan, Location: Vishakhapatnam
ID: 3, Salary: 6000, Name: Renuka, Location: Delhi
ID: 4, Salary: 9000, Name: Archana, Location: Mumbai
ID: 5, Salary: 11000, Name: Sumith, Location: Hyderabad
Conetnets of the resultset after increaing salaries
ID: 1, Salary: 8000, Name: Amit, Location: Hyderabad
ID: 2, Salary: 9000, Name: Kalyan, Location: Vishakhapatnam
ID: 3, Salary: 11000, Name: Renuka, Location: Delhi
ID: 4, Salary: 14000, Name: Archana, Location: Mumbai
ID: 5, Salary: 16000, Name: Sumith, Location: Hyderabad
Record we need to delete:
ID: 2, Salary: 9000, Name: Kalyan, Location: Vishakhapatnam
Contents of the resultset after deleting one records...
ID: 1, Salary: 8000, Name: Amit, Location: Hyderabad
ID: 3, Salary: 11000, Name: Renuka, Location: Delhi
ID: 4, Salary: 14000, Name: Archana, Location: Mumbai
ID: 5, Salary: 16000, Name: Sumith, Location: Hyderabad
Goodbye!
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