java调用 mysql存储过程

DELIMITER //

CREATE PROCEDURE GetEmployeeById(IN empId INT, OUT empName VARCHAR(255))
BEGIN
    SELECT name INTO empName FROM employees WHERE id = empId;
END //

DELIMITER ;

import java.sql.*;

public class CallStoredProcedure {
    public static void main(String[] args) {
        String url = "jdbc:mysql://localhost:3306/mydatabase";
        String user = "username";
        String password = "password";

        try (Connection conn = DriverManager.getConnection(url, user, password)) {
            CallableStatement cstmt = conn.prepareCall("{call GetEmployeeById(?, ?)}");
            cstmt.setInt(1, 123); // 设置输入参数
            cstmt.registerOutParameter(2, Types.VARCHAR); // 注册输出参数

            cstmt.execute();

            String empName = cstmt.getString(2); // 获取输出参数
            System.out.println("Employee Name: " + empName);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}