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編譯錯誤：無法自動裝配運行錯誤：空指針

編譯錯誤截圖：

運行錯誤截圖：

有哪位和我一樣遇到的嗎？怎么解決的？

嘿亞恒

2018-12-31

源自：SpringBoot構(gòu)建電商基礎(chǔ)秒殺項目 2-4

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7 回答

qq_影_53
2019-01-10

紅線是spring注入的問題，后面集成了springMVC應(yīng)該就不會有，為什么會出現(xiàn)紅線還要好好看看spring的原理，學(xué)習(xí)ing

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嘿亞恒提問者
2018-12-31

對了，糾錯之后，回來說一下不能自動裝配這件事，

紅線不影響運行??！

可以自行百度，去除紅線。

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嘿亞恒提問者
2018-12-31

我又仔細想了想，到底改動哪里了。

做了一系列控制變量法實驗之后，我鎖定了一個地方。

就是我手殘把target下面的class文件夾給Mark Directory as? Source Root 了（因為我覺得一大堆文件夾不好點開，改成包模式，能一鍵點開）

后來又給Mark Directory as Excluded 整回來成文件夾

可以運行了。

總結(jié)：

①老師沒做的步驟可以私自做，但后果自己承擔(dān)。

②不能隨便給誰都Mark，同時，Mark Directory as 不是簡單的分分類，都有各自的作用，不能瞎搞?。?！

好了，繼續(xù)學(xué)習(xí)。

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嘿亞恒提問者
2018-12-31

吃個飯回來，再次運行了一下，發(fā)現(xiàn)錯誤竟然變了，

invalid bound statement (not found)

然后又喝了口水，再次嘗試運行，發(fā)現(xiàn)竟然好了，

運行成功了?。。?？？？

這是IDEA累了，歇了一會就好了？？

我可真的什么代碼都沒改?。?！

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嘿亞恒提問者
2018-12-31

項目整體結(jié)構(gòu)及代碼如下：

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嘿亞恒提問者
2018-12-31

完整保錯如下：

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.

2018-12-31 18:32:29.725 ERROR 9060 --- [? ? ? ? ? ?main] o.s.boot.SpringApplication? ? ? ? ? ? ? ?: Application run failed

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'app': Unsatisfied dependency expressed through field 'userDOMapper'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userDOMapper' defined in file [F:\Workspaces\IDEA\mavendemo\target\classes\com\example\mavendemo\dao\UserDOMapper.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 [org/mybatis/spring/boot/autoconfigure/MybatisAutoConfiguration.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 [F:\Workspaces\IDEA\mavendemo\target\classes\mapping\mybatis-generator.xml]'; nested exception is org.apache.ibatis.builder.BuilderException: Error parsing Mapper XML. Cause: java.lang.NullPointerException

at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:586) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]

at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:90) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]

at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:372) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1341) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:572) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:495) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]

at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:317) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]

at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]

at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:315) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]

at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]

at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:759) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]

at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:869) ~[spring-context-5.0.9.RELEASE.jar:5.0.9.RELEASE]

at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:550) ~[spring-context-5.0.9.RELEASE.jar:5.0.9.RELEASE]

at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:140) ~[spring-boot-2.0.5.RELEASE.jar:2.0.5.RELEASE]

at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:780) [spring-boot-2.0.5.RELEASE.jar:2.0.5.RELEASE]

at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:412) [spring-boot-2.0.5.RELEASE.jar:2.0.5.RELEASE]

at org.springframework.boot.SpringApplication.run(SpringApplication.java:333) [spring-boot-2.0.5.RELEASE.jar:2.0.5.RELEASE]

at org.springframework.boot.SpringApplication.run(SpringApplication.java:1277) [spring-boot-2.0.5.RELEASE.jar:2.0.5.RELEASE]

at org.springframework.boot.SpringApplication.run(SpringApplication.java:1265) [spring-boot-2.0.5.RELEASE.jar:2.0.5.RELEASE]

at com.example.mavendemo.App.main(App.java:39) [classes/:na]

Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userDOMapper' defined in file [F:\Workspaces\IDEA\mavendemo\target\classes\com\example\mavendemo\dao\UserDOMapper.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 [org/mybatis/spring/boot/autoconfigure/MybatisAutoConfiguration.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 [F:\Workspaces\IDEA\mavendemo\target\classes\mapping\mybatis-generator.xml]'; nested exception is org.apache.ibatis.builder.BuilderException: Error parsing Mapper XML. Cause: java.lang.NullPointerException

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireByType(AbstractAutowireCapableBeanFactory.java:1436) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1323) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:572) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:495) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]

at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:317) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]

at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]

at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:315) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]

at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]

at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:251) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]

at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1135) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]

at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1062) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]

at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:583) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]

... 19 common frames omitted

Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sqlSessionFactory' defined in class path resource [org/mybatis/spring/boot/autoconfigure/MybatisAutoConfiguration.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 [F:\Workspaces\IDEA\mavendemo\target\classes\mapping\mybatis-generator.xml]'; nested exception is org.apache.ibatis.builder.BuilderException: Error parsing Mapper XML. Cause: java.lang.NullPointerException

at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:590) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1247) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1096) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:535) ~[spring-beans-5.0.9.RELEASE.jar:5.0.9.RELEASE]