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)) {
            // 注册 JDBC 驱动
            Class.forName("com.mysql.cj.jdbc.Driver");

            // 调用存储过程
            CallableStatement cstmt = conn.prepareCall("{call GetEmployeeById(?, ?)}");
            cstmt.setInt(1, 1); // 设置输入参数
            cstmt.registerOutParameter(2, Types.VARCHAR); // 注册输出参数

            cstmt.execute(); // 执行存储过程

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

        } catch (ClassNotFoundException | SQLException e) {
            e.printStackTrace();
        }
    }
}