演示Java如何調用Mysql的過程和函數

這里只演示Java如何調用Mysql的過程和函數

----------------------------------------------------------------------------------過程

#修改mysql語句的結果符為//
mysql > delimiter //

#定義一個過程，獲取users表總記錄數，將10設置到變量count中
create procedure simpleproc(out count int)
begin
    select count(id) into count from users;
end
//

#修改mysql語句的結果符為;
mysql > delimiter ;

#調用過程，將結果覆給變量a，@是定義變量的符號
call simpleproc(@a);

#顯示變量a的值
select @a;

//以下是Java調用Mysql的過程
String sql = "{call simpleproc(?)}";
Connection conn = JdbcUtil.getConnection();
CallableStatement cstmt = conn.prepareCall(sql);
cstmt.registerOutParameter(1,Types.INTEGER);
cstmt.execute();
Integer count = cstmt.getInt(1);
System.out.println("共有" + count + "人");

----------------------------------------------------------------------------------函數

#修改mysql語句的結果符為//
mysql > delimiter //

#定義一個函數，完成字符串拼接
create function hello( s char(20) ) returns char(50) 
return concat('hello，',s,'!');
//

#修改mysql語句的結果符為;
mysql > delimiter ;

#調用函數
select hello('world');

//以下是Java調用Mysql的函數
String sql = "{? = call hello(?)}";
Connection conn = JdbcUtil.getConnection();
CallableStatement cstmt = conn.prepareCall(sql);
cstmt.registerOutParameter(1,Types.VARCHAR);
cstmt.setString(2,"zhaojun");
cstmt.execute();
String value = cstmt.getString(1);
System.out.println(value);
JdbcUtil.close(cstmt);
JdbcUtil.close(conn);