mysql 连接url中useUnicode=truecharacterEncoding=UTF-8 的作用 转载:http://www.cnblogs.com/xuefuwu/archive/2012/05/06/2486577.html ? 我们在连接mysql数据库的时候一般都会在url后面添加useUnicode=truecharacterEncoding=UTF-8 ,但是问什么要添加呢
mysql 连接url中useUnicode=true&characterEncoding=UTF-8 的作用转载:http://www.cnblogs.com/xuefuwu/archive/2012/05/06/2486577.html
?
我们在连接mysql数据库的时候一般都会在url后面添加useUnicode=true&characterEncoding=UTF-8 ,但是问什么要添加呢?
?
添加的作用是:指定字符的编码、解码格式。
? ? ? ? ? ???例如:mysql数据库用的是gbk编码,而项目数据库用的是utf-8编码。这时候如果添加了useUnicode=true&characterEncoding=UTF-8 ,那么作用有如下两个方面:
1. 存数据时:
? ? ?数据库在存放项目数据的时候会先用UTF-8格式将数据解码成字节码,然后再将解码后的字节码重新使用GBK编码存放到数据库中。
2.取数据时:
? ? ?在从数据库中取数据的时候,数据库会先将数据库中的数据按GBK格式解码成字节码,然后再将解码后的字节码重新按UTF-8格式编码数据,最后再将数据返回给客户端。
注意:在xml配置文件中配置数据库utl时,要使用&的转义字符也就是&
? ? ??例如:
HTML中常用的特殊字符:
?
最常用的字符实体(Character Entities)
? | 显示一个空格 | ||
小于 | < | < | |
> | 大于 | > | > |
& | &符号 | & | & |
" | 双引号 | " | " |
其他常用的字符实体(Character Entities)
? | 版权 | © | © |
? | 注册商标 | ® | ® |
× | 乘号 | × | × |
÷ | 除号 | ÷ | ÷ |

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