我们可以在JDBC中返回结果集吗？
是的，就像Java中的其他任何对象一样，我们可以将ResultSet对象作为参数传递给方法，然后从方法中将其返回。
让我们使用CREATE语句在MySQL数据库中创建一个名为MyPlayers 的表，如下所示-
CREATE TABLE MyPlayers( ID INT, First_Name VARCHAR(255), Last_Name VARCHAR(255), Date_Of_Birth date, Place_Of_Birth VARCHAR(255), Country VARCHAR(255), PRIMARY KEY (ID) );
现在，我们将使用INSERT语句在MyPlayers 表中插入7条记录-
insert into MyPlayers values(1, 'Shikhar', 'Dhawan', DATE('1981-12-05'), 'Delhi', 'India');
insert into MyPlayers values(2, 'Jonathan', 'Trott', DATE('1981-04-22'), 'CapeTown', 'SouthAfrica');
insert into MyPlayers values(3, 'Kumara', 'Sangakkara', DATE('1977-10-27'), 'Matale', 'Srilanka');
insert into MyPlayers values(4, 'Virat', 'Kohli', DATE('1988-11-05'), 'Delhi', 'India');
insert into MyPlayers values(5, 'Rohit', 'Sharma', DATE('1987-04-30'), 'Nagpur', 'India');
insert into MyPlayers values(6, 'Ravindra', 'Jadeja', DATE('1988-12-06'), 'Nagpur', 'India');
insert into MyPlayers values(7, 'James', 'Anderson', DATE('1982-06-30'), 'Burnley', 'England');在以下JDBC示例中，该retrieveData()方法与数据库建立连接，并将表MyPlayers的内容检索到ResultSet对象中并返回它。
main方法调用该retrieveData()方法并打印获得的ResultSet的内容。
示例
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class ReturningResultSet {
public static ResultSet retrieveData() throws SQLException{
//注册驱动程序
DriverManager.registerDriver(new com.mysql.jdbc.Driver());
//获得连接
String mysqlUrl = "jdbc:mysql://localhost/mydatabase";
Connection con = DriverManager.getConnection(mysqlUrl, "root", "password");
System.out.println("Connection established......");
//创建一个Statement对象
Statement stmt = con.createStatement();
//检索数据
ResultSet rs = stmt.executeQuery("select * from MyPlayers");
return rs;
}
public static void main(String args[]) throws Exception {
//Getting the ResultSet object from the retrieveData() method
ResultSet rs = retrieveData();
System.out.println("Contents of the Table MyPlayers: ");
while(rs.next()) {
System.out.print(rs.getInt("ID")+", ");
System.out.print(rs.getString("First_Name")+", ");
System.out.print(rs.getString("Last_Name")+", ");
System.out.print(rs.getDate("Date_Of_Birth")+", ");
System.out.print(rs.getString("Place_Of_Birth")+", ");
System.out.print(rs.getString("Country"));
System.out.println();
}
}
}输出结果
Connection established...... Contents of the Table MyPlayers: 1, Shikhar, Dhawan, 1981-12-05, Delhi, India 2, Jonathan, Trott, 1981-04-22, CapeTown, SouthAfrica 3, Kumara, Sangakkara, 1977-10-27, Matale, Srilanka 4, Virat, Kohli, 1988-11-05, Mumbai, India 5, Rohit, Sharma, 1987-04-30, Nagpur, India 6, Ravindra, Jadeja, 1988-12-06, Nagpur, India 7, James, Anderson, 1982-06-30, Burnely, England 8, Ryan, McLaren, 1983-02-09, Kumberly, null