Mysql+使用CallableStatement對象調用存儲過程和存儲函數+java鏈接數據庫

1.存儲過程

（1）定義過程時，使用 DELIMITER $$ 命令將語句的結束符號從分號 ; 臨時改爲兩個 $$，使得過程體中使用的分號被直接傳遞到服務器，而不會被客戶端（如mysql）解釋。

delimiter $$
create procedure find(in num1 int)
begin
	select * from student where stuno = num1;
end$$
delimiter ;
call find(1);

delimiter $$
create procedure add_three_num(in num1 int,in num2 int,in num3 int,out re int)
begin
	set re = num1+num2+num3;
end$$
delimiter ;

2.存儲函數

（1）建立存儲函數的時候報錯 “This function has none of DETERMINISTIC, NO SQL, or READS SQL DATA in its declaration and binary logging is enabled (you *might* want to use the less safe log_bin_trust_function_creators variable) ”，打開my.ini,添加上 log_bin_trust_function_creators=1

delimiter $$
create function add_twonum_function(a int,b int,c int) returns int
begin
	return a+b+c;
end$$
delimiter ;
select add_twonum_function(20,30,40);

3.使用CallableStatement調用

package servletDemo;
import java.sql.CallableStatement;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.Types;

public class JDBCCallableStatement {
	private static final String URL = "jdbc:MySQL://localhost:3306/hotel?&useSSL=false&serverTimezone=UTC";
	private static final String USERNAME = "root";
	private static final String PWD = "root";
	public static void invokeprocedure(){//增刪改
		//調用存儲過程和存儲函數callableStatement
		Connection connection = null;//因爲有可能還麼有用到connection就報錯了 那麼這個對象是空的就不能使用close方法
		CallableStatement cstmt = null;//同理
		try{
			//1導入驅動，加載具體的驅動類
			Class.forName("com.mysql.cj.jdbc.Driver");
			//2與DB建立連接
			connection = DriverManager.getConnection(URL, USERNAME, PWD);
			//3發送sql語句，執行（增刪改）
			//cstmt需要預編譯sql
			//num1 + num2 + num3 = result
			cstmt = connection.prepareCall(   "{ call add_three_num(?,?,?,?) }" ) ;
//			cstmt = connection.prepareCall(sql);
			cstmt.setInt(1,10);
			cstmt.setInt(2,25);
			cstmt.setInt(3,10);
			cstmt.registerOutParameter(4, Types.INTEGER); 
			cstmt.execute();
			int result = cstmt.getInt(4);
			System.out.println(result);
		}catch (ClassNotFoundException e) {//Class.forName()的異常
			e.printStackTrace();
		} catch (SQLException e) {//connection.createStatement()異常
			e.printStackTrace();
		} catch(Exception e) {
			e.printStackTrace();
		}finally{//用finally的原因是無論有沒有異常都需要關閉連接
			try{
				if(cstmt!=null){//執行sql語句
					cstmt.close();
				}
				if(connection!=null){//建立java代碼和數據庫的連接
					connection.close();
				}
			}catch(SQLException e) {//前面兩個close 都會拋SQLException異常
				e.printStackTrace();
			}
		}		
	}
	public static void invokeFunction(){//增刪改
		//調用存儲過程和存儲函數callableStatement
		Connection connection = null;//因爲有可能還麼有用到connection就報錯了 那麼這個對象是空的就不能使用close方法
		CallableStatement cstmt = null;//同理
		try{
			//1導入驅動，加載具體的驅動類
			Class.forName("com.mysql.cj.jdbc.Driver");
			//2與DB建立連接
			connection = DriverManager.getConnection(URL, USERNAME, PWD);
			//3發送sql語句，執行（增刪改）
			//cstmt需要預編譯sql
			//num1 + num2 = result
			String sql = "{? =  call add_twonum_function(?,?,?)}";
			cstmt = connection.prepareCall(sql) ;
//			cstmt = connection.prepareCall(sql);
			cstmt.registerOutParameter(1, Types.INTEGER); 
			cstmt.setInt(2,10);
			cstmt.setInt(3,10);
			cstmt.setInt(4,10);
//			cstmt.registerOutParameter(4, Types.INTEGER); 
			cstmt.execute();
			int result = cstmt.getInt(1);
			System.out.println(result);
		}catch (ClassNotFoundException e) {//Class.forName()的異常
			e.printStackTrace();
		} catch (SQLException e) {//connection.createStatement()異常
			e.printStackTrace();
		} catch(Exception e) {
			e.printStackTrace();
		}finally{//用finally的原因是無論有沒有異常都需要關閉連接
			try{
				if(cstmt!=null){//執行sql語句
					cstmt.close();
				}
				if(connection!=null){//建立java代碼和數據庫的連接
					connection.close();
				}
			}catch(SQLException e) {//前面兩個close 都會拋SQLException異常
				e.printStackTrace();
			}
		}		
	}
	
	public static void main(String [] args){
		invokeprocedure();
		invokeFunction();
		
	}
}