Mybatis中一次执行多条语句

有时候需要批量更新一些数据，会用到`<foreach></foreach>`标签来，其实就是用分号（;）隔开一次执行多条sql语句，比如看下面sql语句。

```
<update id="update">
	<foreach collection="list" item="item" index="index" separator=";">
	update t_user set nickname = #{item.nickname}
	where id = #{item.id}
	</foreach>
</update>
```

如果什么都没设置的话是会报错的

1、需要在数据库连接信息里配置：allowMultiQueries=true 如：
```
url: jdbc:mysql://localhost:3306/blog?serverTimezone=Asia/Shanghai&useAffectedRows=true&useUnicode=true&characterEncoding=utf-8&allowMultiQueries=true&useSSL=false

```

2、如果用的是 Durid 数据库连接池的话那么 filters 不要配置 wall

下面配置信息我加上了allowMultiQueries=true，并且注释掉了 wall 配置，这样就可以了

```
spring: 
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource
    druid: 
      url: jdbc:mysql://localhost:3306/blog?serverTimezone=Asia/Shanghai&useAffectedRows=true&useUnicode=true&characterEncoding=utf-8&allowMultiQueries=true&useSSL=false
      username: root
      password: 123456
      initial-size: 5
      min-idle: 5
      max-active: 20
      max-wait: 60000
      time-between-eviction-runs-millis: 60000
      min-evictable-idle-time-millis: 300000
      validation-query: SELECT 1 FROM DUAL
      test-while-idle: true
      test-on-borrow: false
      test-on-return: false
      pool-prepared-statements: true
      filters: stat,logback #,wall
      max-pool-prepared-statement-per-connection-size: 20
      use-global-data-source-stat: true
      connection-properties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=500
```