MySql+Mybatis+Druid之SqlException：sql injection violation, multi-statement not allow

接上一篇博客：《数据库优化之MyBatis批量删除、更新》

Druid是阿里巴巴，开发的一个数据库连接池工具，经历过多次双十一的洗礼，它的性能已经能够满足国内大多数项目的需求。

异常一：

项目中启用Druid的统计管理，在执行批量修改时：提示Error updating database.  Cause: java.sql.SQLException: sql injection violation, multi-statement not allow 。

提示：违反sql注入：多声明不被允许

以下是栈异常输出：

Caused by: java.sql.SQLException: sql injection violation, multi-statement not allow : UPDATE
            t_single_project_score
             SET update_time=now() ,
            is_delete = 1 ,
            operator =? 
            WHERE
             
                student_id IN (?)
             
             
                AND school_year IN(
                ?
                )
             
            AND is_delete = 0
         ; 
            UPDATE
            t_single_project_score
             SET update_time=now() ,
            is_delete = 1 ,
            operator =? 
            WHERE
             
                student_id IN (?)
             
             
                AND school_year IN(
                ?
                )
             
            AND is_delete = 0
        at com.alibaba.druid.wall.WallFilter.checkInternal(WallFilter.java:800)
	at com.alibaba.druid.wall.WallFilter.connection_prepareStatement(WallFilter.java:251)
	at com.alibaba.druid.filter.FilterChainImpl.connection_prepareStatement(FilterChainImpl.java:473)
	at com.alibaba.druid.filter.FilterAdapter.connection_prepareStatement(FilterAdapter.java:929)
	at com.alibaba.druid.filter.FilterChainImpl.connection_prepareStatement(FilterChainImpl.java:473)
	at com.alibaba.druid.filter.FilterAdapter.connection_prepareStatement(FilterAdapter.java:929)
	at com.alibaba.druid.filter.FilterEventAdapter.connection_prepareStatement(FilterEventAdapter.java:122)
	at com.alibaba.druid.filter.FilterChainImpl.connection_prepareStatement(FilterChainImpl.java:473)
	at com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl.prepareStatement(ConnectionProxyImpl.java:342)
	at com.alibaba.druid.pool.DruidPooledConnection.prepareStatement(DruidPooledConnection.java:349)
	at com.p6spy.engine.wrapper.ConnectionWrapper.prepareStatement(ConnectionWrapper.java:119)
	at org.apache.ibatis.executor.statement.PreparedStatementHandler.instantiateStatement(PreparedStatementHandler.java:87)
	at org.apache.ibatis.executor.statement.BaseStatementHandler.prepare(BaseStatementHandler.java:88)
	at org.apache.ibatis.executor.statement.RoutingStatementHandler.prepare(RoutingStatementHandler.java:59)
	at org.apache.ibatis.executor.SimpleExecutor.prepareStatement(SimpleExecutor.java:85)
	at org.apache.ibatis.executor.SimpleExecutor.doUpdate(SimpleExecutor.java:49)
	at org.apache.ibatis.executor.BaseExecutor.update(BaseExecutor.java:117)
	at org.apache.ibatis.executor.CachingExecutor.update(CachingExecutor.java:76)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:483)
	at org.apache.ibatis.plugin.Plugin.invoke(Plugin.java:63)
	at com.sun.proxy.$Proxy44.update(Unknown Source)
	at org.apache.ibatis.session.defaults.DefaultSqlSession.update(DefaultSqlSession.java:198)
	at org.apache.ibatis.session.defaults.DefaultSqlSession.delete(DefaultSqlSession.java:213)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:483)
	at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:433)
	... 52 more

通过异常栈输出出现异常如何分析解决？

在输出的日志里，找到关键信息：

at com.alibaba.druid.wall.WallFilter.checkInternal(WallFilter.java:800)

这是在spring-db.xml的wall-filter这个 bean中报出的异常：

在这个WallFilter找到checkInternal方法，就会看到提示的错误信息前半部分：sql injection violation

查看check()方法-->checkInternal()方法

找到异常后半段：multi-statement not allow。造成打印这个异常消息的原因是config.ismultiStatementAllow()为false

解决方法：把multiStatementAllow修改成true即可

了解wall-filter： 通过官方文档配置

异常二：You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near

com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 
		'UPDATE
		            t_single_project_score
		             SET update_time=now() , '

参考：

【sql关键字冲突】https://www.cnblogs.com/zzxbest/archive/2011/09/22/2185029.html

【sql关键字冲突】http://blog.csdn.net/qq_34698126/article/details/53128746

解决方法：这个问题一直报sql语法问题，删除wall-filter的bean和wall-config的bean，同时在jdbc上加上allowMultiQueries=true&，问题得到了解决。

分析：wall-filter会拦截多次声明请求的循环sql语句，即使设置为true，还会检测到sql语句间的';'分号会视为sql已经结束，所以有sql循环，第二个sql语句就会报出异常。

以上不是最终的解决方案，希望遇到过这个问题的亲们，可以多多留言与小编交流。

祝好运