mysql blob 存取乱码问题

1.mysql数据库连接字符编码 
url ="jdbc:mysql://localhost:8080/test?useUnicode=true&characterEncoding=UTF-8"; 

2.查看创表的字符集 
show  create table  tablename; 
3.查看数据库的编码 
show variables like '%char%';

4.修改字符编码

set character_set_server=utf8; 
set character_set_database=utf8; 
show variables like '%char%'; 

5.使用 CONVERT(content USING utf8)

SELECT CONVERT(content USING utf8) as content FROM XXX；