字符编码问题mysql

2019-02-27 07:32:17.108 ERROR 21745 --- [nio-8086-exec-2] c.h.h.rest.configurer.WebMvcConfigurer   : 接口[/flyfish/h5/user/register]出
现异常 :[{}]

org.springframework.jdbc.UncategorizedSQLException:
### Error querying database.  Cause: java.sql.SQLException: Illegal mix of collations (utf8_general_ci,IMPLICIT) and (utf8mb4_general_ci,COERCIBLE) for operation '='
### The error may exist in com/hn/haoniu/businesscore/dao/UserMapper.java (best guess)
### The error may involve com.hn.haoniu.businesscore.dao.UserMapper.selectOne-Inline
### The error occurred while setting parameters
### SQL: SELECT id,invite_code,recommend_user_id,nick_name,phone,password,real_name,sex,area,user_type,robot_type,head_img,salt,lei_type,token_id,create_time,update_time,del_flag  FROM user  WHERE  nick_name = ?
### Cause: java.sql.SQLException: Illegal mix of collations (utf8_general_ci,IMPLICIT) and (utf8mb4_general_ci,COERCIBLE) for operation '='
; uncategorized SQLException for SQL []; SQL state [HY000]; error code [1267]; Illegal mix of collations (utf8_general_ci,IMPLICIT) and (utf8mb4_general_ci,COERCIBLE) for operation '='; nested exception is java.sql.SQLException: Illegal mix of collations (utf8_general_ci,IMPLICIT) and (utf8mb4_general_ci,COERCIBLE) for operation '='
        at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:84) ~[spring-jdbc-4.3.9.RELEASE.jar:4.3.9.RELEASE]
        at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:81) ~[spring-jdbc-4.3.9.RELEASE.jar:4.3.9.RELEASE]
        at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:81) ~[spring-jdbc-4.3.9.RELEASE.jar:4.3.9.RELEASE]
        at org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:73) ~[mybatis-spring-1.3.1.jar:1.3.1]
        at org.mybatis.spring.SqlSessionTemplate$SqlSessionInte

解决方法

java.sql.SQLException: Illegal mix of collations (latin1_swedish_ci,IMPLICIT) and (utf8_general_ci,COERCIBLE) for operation '='，意思是说字符编码不同，不能进行比较，也就是说数据库内部的编码都不同，有的数据是latin1_swedish_ci,有的数据是utf8_general_ci,，所以解决此问题的核心就是将数据库全部的编码进行统一。

一、查看数据库编码，使用sql语句：show variables like 'character_set_%';

正确的以下图：

若是编码不对，可以使用如下sql语句进行修改：

set character_set_client=utf8;
set character_set_connection=utf8;
set character_set_database=utf8;
set character_set_results=utf8;
set character_set_server=utf8;
set character_set_system=utf8;

 

二、查看排序规则，使用sql语句：show variables like 'collation_%';

正确的以下图：

若是不对，可以使用如下sql语句进行修改：

set collation_connection=utf8;
set collation_database=utf8;
set collation_server=utf8;