解决 Caused by: org.apache.ibatis.builder.BuilderException: Parsing error was found in mapping #{}. 报错

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问题描述：

当我们使用mybatis-plus书写sql语句，sql 语句中 #{} 忘加变量时，便会报以下错误

报错堆栈信息如下

	
org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'appointmentController': Unsatisfied dependency expressed through field 'service'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'appointmentServiceImpl': Unsatisfied dependency expressed through field 'userEquipmentService'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userEquipmentServiceImpl': Unsatisfied dependency expressed through field 'equipmentService'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'equipmentServiceImpl': Unsatisfied dependency expressed through field 'baseMapper'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'equipmentMapper' defined in file [D:\fy\back\10-24dxyq\yx-api-dxyq\target\classes\com\yxkj\dxyq\mapper\EquipmentMapper.class]: Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: org.apache.ibatis.builder.BuilderException: Parsing error was found in mapping #{}.  Check syntax #{property|(expression), var1=value1, var2=value2, ...} 
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:587) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:91) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:373) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1350) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:580) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:503) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:317) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:315) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:760) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:869) ~[spring-context-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:550) ~[spring-context-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:140) ~[spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:759) [spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:395) [spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:327) [spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1255) [spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1243) [spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
	at com.yxkj.dxyq.DxyqApplication.main(DxyqApplication.java:28) [classes/:na]
Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'appointmentServiceImpl': Unsatisfied dependency expressed through field 'userEquipmentService'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userEquipmentServiceImpl': Unsatisfied dependency expressed through field 'equipmentService'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'equipmentServiceImpl': Unsatisfied dependency expressed through field 'baseMapper'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'equipmentMapper' defined in file [D:\fy\back\10-24dxyq\yx-api-dxyq\target\classes\com\yxkj\dxyq\mapper\EquipmentMapper.class]: Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: org.apache.ibatis.builder.BuilderException: Parsing error was found in mapping #{}.  Check syntax #{property|(expression), var1=value1, var2=value2, ...} 
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:587) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:91) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:373) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1350) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:580) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:503) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:317) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:315) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:251) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1138) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1065) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:584) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	... 19 common frames omitted
Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userEquipmentServiceImpl': Unsatisfied dependency expressed through field 'equipmentService'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'equipmentServiceImpl': Unsatisfied dependency expressed through field 'baseMapper'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'equipmentMapper' defined in file [D:\fy\back\10-24dxyq\yx-api-dxyq\target\classes\com\yxkj\dxyq\mapper\EquipmentMapper.class]: Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: org.apache.ibatis.builder.BuilderException: Parsing error was found in mapping #{}.  Check syntax #{property|(expression), var1=value1, var2=value2, ...} 
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:587) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:91) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:373) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1350) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:580) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:503) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:317) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:315) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:251) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1138) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1065) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:584) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	... 32 common frames omitted
Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'equipmentServiceImpl': Unsatisfied dependency expressed through field 'baseMapper'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'equipmentMapper' defined in file [D:\fy\back\10-24dxyq\yx-api-dxyq\target\classes\com\yxkj\dxyq\mapper\EquipmentMapper.class]: Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: org.apache.ibatis.builder.BuilderException: Parsing error was found in mapping #{}.  Check syntax #{property|(expression), var1=value1, var2=value2, ...} 
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:587) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:91) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:373) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1350) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:580) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:503) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:317) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:315) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:251) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1138) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1065) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:584) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	... 45 common frames omitted
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'equipmentMapper' defined in file [D:\fy\back\10-24dxyq\yx-api-dxyq\target\classes\com\yxkj\dxyq\mapper\EquipmentMapper.class]: Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: org.apache.ibatis.builder.BuilderException: Parsing error was found in mapping #{}.  Check syntax #{property|(expression), var1=value1, var2=value2, ...} 
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1708) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:581) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:503) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:317) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:315) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:251) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1138) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1065) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:584) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	... 58 common frames omitted
Caused by: java.lang.IllegalArgumentException: org.apache.ibatis.builder.BuilderException: Parsing error was found in mapping #{}.  Check syntax #{property|(expression), var1=value1, var2=value2, ...} 
	at org.mybatis.spring.mapper.MapperFactoryBean.checkDaoConfig(MapperFactoryBean.java:83) ~[mybatis-spring-2.0.5.jar:2.0.5]
	at org.springframework.dao.support.DaoSupport.afterPropertiesSet(DaoSupport.java:44) ~[spring-tx-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1767) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1704) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
	... 68 common frames omitted
Caused by: org.apache.ibatis.builder.BuilderException: Parsing error was found in mapping #{}.  Check syntax #{property|(expression), var1=value1, var2=value2, ...} 
	at org.apache.ibatis.builder.SqlSourceBuilder$ParameterMappingTokenHandler.parseParameterMapping(SqlSourceBuilder.java:152) ~[mybatis-3.5.6.jar:3.5.6]
	at org.apache.ibatis.builder.SqlSourceBuilder$ParameterMappingTokenHandler.buildParameterMapping(SqlSourceBuilder.java:92) ~[mybatis-3.5.6.jar:3.5.6]
	at org.apache.ibatis.builder.SqlSourceBuilder$ParameterMappingTokenHandler.handleToken(SqlSourceBuilder.java:87) ~[mybatis-3.5.6.jar:3.5.6]
	at org.apache.ibatis.parsing.GenericTokenParser.parse(GenericTokenParser.java:77) ~[mybatis-3.5.6.jar:3.5.6]
	at org.apache.ibatis.builder.SqlSourceBuilder.parse(SqlSourceBuilder.java:50) ~[mybatis-3.5.6.jar:3.5.6]
	at org.apache.ibatis.scripting.defaults.RawSqlSource.<init>(RawSqlSource.java:46) ~[mybatis-3.5.6.jar:3.5.6]
	at org.apache.ibatis.scripting.xmltags.XMLLanguageDriver.createSqlSource(XMLLanguageDriver.java:60) ~[mybatis-3.5.6.jar:3.5.6]
	at com.baomidou.mybatisplus.core.MybatisMapperAnnotationBuilder.buildSqlSourceFromStrings(MybatisMapperAnnotationBuilder.java:641) ~[mybatis-plus-core-3.4.1.jar:3.4.1]
	at com.baomidou.mybatisplus.core.MybatisMapperAnnotationBuilder.buildSqlSource(MybatisMapperAnnotationBuilder.java:626) ~[mybatis-plus-core-3.4.1.jar:3.4.1]
	at com.baomidou.mybatisplus.core.MybatisMapperAnnotationBuilder.lambda$parseStatement$2(MybatisMapperAnnotationBuilder.java:296) ~[mybatis-plus-core-3.4.1.jar:3.4.1]
	at java.util.Optional.ifPresent(Optional.java:159) ~[na:1.8.0_161]
	at com.baomidou.mybatisplus.core.MybatisMapperAnnotationBuilder.parseStatement(MybatisMapperAnnotationBuilder.java:295) ~[mybatis-plus-core-3.4.1.jar:3.4.1]
	at com.baomidou.mybatisplus.core.MybatisMapperAnnotationBuilder.parse(MybatisMapperAnnotationBuilder.java:110) ~[mybatis-plus-core-3.4.1.jar:3.4.1]
	at com.baomidou.mybatisplus.core.MybatisMapperRegistry.addMapper(MybatisMapperRegistry.java:83) ~[mybatis-plus-core-3.4.1.jar:3.4.1]
	at com.baomidou.mybatisplus.core.MybatisConfiguration.addMapper(MybatisConfiguration.java:152) ~[mybatis-plus-core-3.4.1.jar:3.4.1]
	at org.mybatis.spring.mapper.MapperFactoryBean.checkDaoConfig(MapperFactoryBean.java:80) ~[mybatis-spring-2.0.5.jar:2.0.5]
	... 71 common frames omitted
Caused by: java.lang.StringIndexOutOfBoundsException: String index out of range: 0
	at java.lang.String.charAt(String.java:658) ~[na:1.8.0_161]
	at org.apache.ibatis.builder.ParameterExpression.parse(ParameterExpression.java:44) ~[mybatis-3.5.6.jar:3.5.6]
	at org.apache.ibatis.builder.ParameterExpression.<init>(ParameterExpression.java:39) ~[mybatis-3.5.6.jar:3.5.6]
	at org.apache.ibatis.builder.SqlSourceBuilder$ParameterMappingTokenHandler.parseParameterMapping(SqlSourceBuilder.java:148) ~[mybatis-3.5.6.jar:3.5.6]
	... 86 common frames omitted

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原因分析：

该错误是由于MyBatis在解析映射文件时发现了语法错误，在映射文件中的#{property|(expression), var1=value1, var2=value2, …}部分，确保语法正确。

回顾代码处

`sql 语句中 #{} 未加变量userid，故而报错

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举一反三：

其他可能导致该错误的原因

1. 语法错误：在映射文件中，#{property|(expression), var1=value1, var2=value2, ...}部分的语法不正确
2. 变量未定义：在使用#{property|(expression), var1=value1, var2=value2, ...}时，如果其中引用了未定义的变量，将会引发此错误
3. 表达式错误：如果expression表达式本身存在错误，也会导致此错误

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解决方案:

补上缺失的变量 useri 至 #{} 中即可

重新运行项目，如下所示成功

检查表达式是否正确，以及是否遗漏要使用的变量，当然前提是引入了对应的依赖

查缺补漏！！！

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