您可以使用 CallableStatement 接口調(diào)用 SQL 存儲過程。 Callable 語句可以具有輸入?yún)?shù)、輸出參數(shù)或兩者。
您可以使用 prepareCall() 創(chuàng)建 CallableStatement(接口)的對象> Connection 接口的方法。此方法接受一個表示調(diào)用存儲過程的查詢的字符串變量,并返回一個 CallableStatement 對象。
假設您有一個過程名稱 myProcedure 在數(shù)據(jù)庫,您可以準備一個可調(diào)用語句:
//Preparing a CallableStatement CallableStatement cstmt = con.prepareCall("{call myProcedure(?, ?, ?)}");
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然后,您可以使用 CallableStatement 接口的 setter 方法為占位符設置值,并使用 execute() 方法執(zhí)行可調(diào)用語句,如下所示。
cstmt.setString(1, "Raghav"); cstmt.setInt(2, 3000); cstmt.setString(3, "Hyderabad"); cstmt.execute();
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如果該過程沒有輸入值,您只需準備可調(diào)用語句并執(zhí)行它,如下所示:
CallableStatement cstmt = con.prepareCall("{call myProcedure()}"); cstmt.execute();
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示例
假設 MySQL 數(shù)據(jù)庫中有一個名為 Dispatches 的表,其中包含以下數(shù)據(jù):
+--------------+------------------+------------------+----------------+ | 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 | +--------------+------------------+------------------+----------------+
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如果我們創(chuàng)建了一個名為 myProcedure 的過程來從此表中檢索值,如下所示:
Create procedure myProcedure () -> BEGIN -> SELECT * FROM Dispatches; -> END //
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示例
下面是一個使用 JDBC 程序調(diào)用上述存儲過程的 JDBC 示例。
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 { //Registering the Driver DriverManager.registerDriver(new com.mysql.jdbc.Driver()); //Getting the connection String mysqlUrl = "jdbc:mysql://localhost/sampleDB"; Connection con = DriverManager.getConnection(mysqlUrl, "root", "password"); System.out.println("Connection established......"); //Preparing a CallableStateement CallableStatement cstmt = con.prepareCall("{call myProcedure()}"); //Retrieving the result 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("Time of Dispatch: "+rs.getTime("Time_Of_Dispatch")); System.out.println("Location: "+rs.getString("Location")); System.out.println(); } } }
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輸出
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
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