Java存储过程调用CallableStatement的方法

drop procedure if exists pr_add;
-- 计算两个数之和
create procedure pr_add
(
  a int,
  b int
)
begin
  declare c int;
  if a is null then
   set a = 0;
  end if;
  if b is null then
   set b = 0;
  end if;
  set c = a + b;
  select c as sum;
/*return c;- 不能在 MySQL 存储过程中使用。return 只能出现在函数中。*/
end;

set @a = 10;
set @b = 20;
call pr_add(@a, @b);

CREATE PROCEDURE add_pro(a int,b int,out sum int)
BEGIN
set sum = a + b;
END;

package ch13;
import java.sql.*;

/**
 * Created by Jiqing on 2016/12/20.
 */
public class ConnMySql {
  public static void main(String[] args) throws Exception {
    // 1.加载驱动
    Class.forName("com.mysql.jdbc.Driver");

    // try() {} 语法中小括号中的资源会自动回收

    try (
      // 2.连接数据库
      Connection conn = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/tpshop","root","123456");
      CallableStatement cstmt = conn.prepareCall("{call add_pro(?,?,?)}")
    )
    {
      cstmt.setInt(1,4);
      cstmt.setInt(2,5);
      cstmt.registerOutParameter(3,Types.INTEGER);
      cstmt.execute();
      System.out.println("执行结果是:"+cstmt.getInt(3));
    }
  }
}