1、注解

 @CacheNamespace(flushInterval = 100000,eviction = LruCache.class,readWrite = false,size = 1024)

2、xml配置

   <cache eviction= "LRU" flushInterval= "100000" readOnly= "true" size= "1024"/>

二级缓存，配置文件和接口注释是不能够配合使用的。只能通过全注解的方式才能够生效；

3、问题是以上两个不能同时使用，会报错

mybatis puls 同时使用sql和 QueryWrapper查询

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'baseDrugController': Unsatisfied dependency expressed through field 'baseDrugService'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'baseDrugServiceImpl': Unsatisfied dependency expressed through field 'baseMapper'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'baseDrugMapper' defined in file [D:\yuguang\DrugGuide\ruoyi-business\target\classes\com\ruoyi\drug\mapper\BaseDrugMapper.class]: Unsatisfied dependency expressed through bean property 'sqlSessionFactory'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sqlSessionFactory' defined in class path resource [com/baomidou/mybatisplus/autoconfigure/MybatisPlusAutoConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.apache.ibatis.session.SqlSessionFactory]: Factory method 'sqlSessionFactory' threw exception; nested exception is org.springframework.core.NestedIOException: Failed to parse mapping resource: 'file [D:\yuguang\DrugGuide\ruoyi-business\target\classes\mapper\drug\DrugPurchaseDetailMapper.xml]'; nested exception is java.lang.IllegalArgumentException: Caches collection already contains value for com.ruoyi.drug.mapper.DrugPurchaseDetailMapperat org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.resolveFieldValue(AutowiredAnnotationBeanPostProcessor.java:659)at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:639)at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:119)at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:399)at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1431)at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:619)at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:542)at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335)at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234)at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333)at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208)at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:953)at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:918)at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:583)at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:145)at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:780)at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:453)at org.springframework.boot.SpringApplication.run(SpringApplication.java:343)at org.springframework.boot.SpringApplication.run(SpringApplication.java:1370)at org.springframework.boot.SpringApplication.run(SpringApplication.java:1359)at com.ruoyi.RuoYiApplication.main(RuoYiApplication.java:21)at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)at java.base/java.lang.reflect.Method.invoke(Method.java:566)at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49)
Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'baseDrugServiceImpl': Unsatisfied dependency expressed through field 'baseMapper'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'baseDrugMapper' defined in file [D:\yuguang\DrugGuide\ruoyi-business\target\classes\com\ruoyi\drug\mapper\BaseDrugMapper.class]: Unsatisfied dependency expressed through bean property 'sqlSessionFactory'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sqlSessionFactory' defined in class path resource [com/baomidou/mybatisplus/autoconfigure/MybatisPlusAutoConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.apache.ibatis.session.SqlSessionFactory]: Factory method 'sqlSessionFactory' threw exception; nested exception is org.springframework.core.NestedIOException: Failed to parse mapping resource: 'file [D:\yuguang\DrugGuide\ruoyi-business\target\classes\mapper\drug\DrugPurchaseDetailMapper.xml]'; nested exception is java.lang.IllegalArgumentException: Caches collection already contains value for com.ruoyi.drug.mapper.DrugPurchaseDetailMapperat org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.resolveFieldValue(AutowiredAnnotationBeanPostProcessor.java:659)at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:639)at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:119)at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:399)at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1431)at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:619)at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:542)at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:335)at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234)at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:333)at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:208)at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:276)

4、解决办法

在mapper.xml中加上配置，然后再mapper接口加上注解

@CacheNamespaceRef(name = "com.ruoyi.drug.mapper.DrugPurchaseDetailMapper")
public interface DrugPurchaseDetailMapper extends BaseMapper<DrugPurchaseDetail> {

5、引用其他博客的解读细节

讲一下@CacheNamespace和@CacheNamespaceRef这俩注解的区别以及使用心得。

@CacheNamespace，作用于mapper接口上面，是用来实现二级缓存的，点击查看源码可以发现，东西也不多，主要讲的是缓存的实现类，如果不指定实现类的话，默认就是PerpetualCache（实际上就是hashmap实现的）

我们平常使用默认方式的的时候可以直接使用，如果使用自定义的方式，则需要指明实现类，如图 implementation = MybatisCache.class

这里讲一下存在的一个问题：当使用该注解的时候，你去查询的时候，使用到的查询能被缓存起来，但是，加入你这个查询SQL调用的是xml文件里面的，此时，是不会被缓存的，因为我们有时候会使用很多注解或者tk.mapper，这个时候是不会走xml，所以这个缓存我们用不上，此时存在一个解决方案，在xml文件里面也用上缓存，如下就代表开启使用缓存了，这个方式进行的话存在同上面类似的问题

这个存在的问题是xml里面走的SQL是可以被缓存的，但是你接口层的注解之类的SQL是不会被缓存，那有的人就说了，我把@CacheNamespace注解和cache标签一起使用不就行了嘛，但实际上是不行的。
那么如何同时去满足这个问题呢
@CacheNamespaceRef 来解决这个问题，也就是在接口上使用这个注解，把接口上的@CacheNamespace注解替换成@CacheNamespaceRef ，同时的话xml文件里面使用cache标签，
使用@CacheNamespaceRef注解要注意一点，要指明value或者name,如果不指明则会报错

org.apache.ibatis.builder.BuilderException: Should be specified either value() or name() attribute in the @CacheNamespaceRef

• 1

查看该注解源码，value就是当前类，name是你使用的Mapper接口的全限定名

使用如下三种方式：

顺便说一下，如果某个SQL不想被缓存，可以单独处理一下：
1、SQL走的是xml文件查询：配置useCache=“false”

2、SQL走的是注解形式：@Options(useCache=false)

如果你走的是xml，你在注解上使用这个注解，将不会起效

这些便是我对他俩的理解和使用过程