什么是存储过程？如何使用JDBC程序调用存储过程？
存储过程是子例程，是SQL语句的一部分，存储在SQL目录中。所有可以访问关系数据库的应用程序（Java，Python，PHP等）都可以访问这些过程。
存储过程包含IN和OUT参数，或同时包含这两个参数。如果您使用SELECT语句，它们可能会返回结果集，它们可以返回多个结果集。
示例
假设我们在MySQL数据库中有一个名为Dispatches的表，其中包含以下数据：
+--------------+------------------+------------------+------------------+ | Product_Name | Date_Of_Dispatch | Time_Of_Dispatch | Location | +--------------+------------------+------------------+------------------+ | KeyBoard | 1970-01-19 | 08:51:36 | Hyderabad | | Earphones | 1970-01-19 | 05:54:28 | Vishakhapatnam | | Mouse | 1970-01-19 | 04:26:38 | Vijayawada | +--------------+------------------+------------------+------------------+
并且如果我们创建了一个名为myProcedure的过程来从该表中检索值，如下所示：
Create procedure myProcedure () -> BEGIN -> SELECT * from Dispatches; -> END //
示例
以下是一个JDBC示例，该示例使用JDBC程序调用上述存储过程。
import java.sql.CallableStatement;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
public class CallingProcedure {
public static void main(String args[]) throws SQLException {
//注册驱动程序
DriverManager.registerDriver(new com.mysql.jdbc.Driver());
//获得连接
String mysqlUrl = "jdbc:mysql://localhost/sampleDB";
Connection con = DriverManager.getConnection(mysqlUrl, "root", "password");
System.out.println("Connection established......");
//准备一个CallableStatement-
CallableStatement cstmt = con.prepareCall("{call myProcedure()}");
//检索结果
ResultSet rs = cstmt.executeQuery();
while(rs.next()) {
System.out.println("Product Name: "+rs.getString("Product_Name"));
System.out.println("Date Of Dispatch: "+rs.getDate("Date_Of_Dispatch"));
System.out.println("Date Of Dispatch: "+rs.getTime("Time_Of_Dispatch"));
System.out.println("Location: "+rs.getString("Location"));
System.out.println();
}
}
}输出结果
Connection established...... Product Name: KeyBoard Date of Dispatch: 1970-01-19 Time of Dispatch: 08:51:36 Location: Hyderabad Product Name: Earphones Date of Dispatch: 1970-01-19 Time of Dispatch: 05:54:28 Location: Vishakhapatnam Product Name: Mouse Date of Dispatch: 1970-01-19 Time of Dispatch: 04:26:38 Location: Vijayawada