java mysql 存储过程

CREATE PROCEDURE procedure_name ([IN | OUT | INOUT] parameter_name data_type[, ...])
BEGIN
    -- 存储过程的SQL语句块
END

CREATE PROCEDURE calc_circle(IN r INT, OUT circumference FLOAT, OUT area FLOAT)
BEGIN
    SET circumference = 2 * PI() * r;
    SET area = PI() * r * r;
END

import java.sql.*;

public class CallSPDemo {
    public static void main(String[] args) {
        Connection conn = null;
        CallableStatement cs = null;
        
        try {
            // 连接MySQL数据库
            String url = "jdbc:mysql://localhost:3306/test";
            String user = "root";
            String password = "123456";
            conn = DriverManager.getConnection(url, user, password);
            
            // 创建CallableStatement对象
            String sp = "{CALL calc_circle(?, ?, ?)}";
            cs = conn.prepareCall(sp);
            
            // 设置输入参数
            cs.setInt(1, 5);
            
            // 设置输出参数类型
            cs.registerOutParameter(2, Types.FLOAT);
            cs.registerOutParameter(3, Types.FLOAT);
            
            // 执行存储过程
            cs.execute();
            
            // 获取输出参数值
            float circum = cs.getFloat(2);
            float area = cs.getFloat(3);
            
            // 输出结果
            System.out.println("Circumference: " + circum);
            System.out.println("Area: " + area);
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            try {
                if (cs != null) cs.close();
                if (conn != null) conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}