How to use JDBC callablestatement The wasnull () method is called to check whether the value of the last out parameter is SQL null

This example shows you how to use CallableStatement.wasNull() Method is called to view the last OUT Whether the value of the parameter is SQL NULL.

package org.kodejava.jdbc; import java.math.BigDecimal; import java.sql.Connection; import java.sql.CallableStatement; import java.sql.DriverManager; import java.sql.Types; import java.sql.SQLException; public class WasNullExample { private static final String URL = "jdbc:mysql://localhost/kodejava"; private static final String USERNAME = "root"; private static final String PASSWORD = ""; public static void main(String[] args) { try (Connection connection = DriverManager.getConnection(URL, USERNAME, PASSWORD)) { // Prepares a call to the sored procedure String query = "call Get_Product_By_Price2(?, ?)"; CallableStatement cb = connection.prepareCall(query); // Sets the input parameter cb.setBigDecimal(1, new BigDecimal("50")); // Registers the OUT parameter cb.registerOutParameter(2, Types.VARCHAR); // Executes the query cb.executeQuery(); // Gets the OUT parameter value cb.getString(2); // Checks if the last OUT parameter has value of SQL NULL. // This method should be called only after calling a // getter method; otherwise, there is no value to use in // determining whether it is null or not. if (cb.wasNull()) { System.out.println("Product has an SQL NULL value"); } else { System.out.println("Product: " + cb.getString(2)); } } catch (SQLException e) { e.printStackTrace(); } } } 

This is the stored procedure script we called in the above example. .

DELIMITER ;; DROP PROCEDURE IF EXISTS Get_Product_By_Price2;; CREATE PROCEDURE Get_Product_By_Price2( IN product_price DECIMAL(10, 2), OUT product_name VARCHAR(50)) BEGIN SELECT NAME INTO product_name FROM products WHERE price = product_price; END;; DELIMITER ; 

Maven Dependencies

<!-- https://search.maven.org/remotecontent?filepath=mysql/mysql-connector-java/8.0.28/mysql-connector-java-8.0.28.jar --> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>8.0.28</version> </dependency>