java未能实例化服务。FileService构造函数引发异常；
--------------this is my file service-------------------- i am using spring boot 2.2.2
@Service public class FileService {
public final Path fileStoreLocation;
@Autowired
public FileService(File file) throws FileStorageExecption {
this.fileStoreLocation= Paths.get(file.getFile_path()).toAbsolutePath().normalize();
try{
Files.createDirectories(this.fileStoreLocation);
}
catch (Exception e){
throw new FileStorageExecption("--------Create directories exception-------");
}
}
public String storeFile(MultipartFile file) throws FileStorageExecption {
String fileName= StringUtils.cleanPath(file.getOriginalFilename());
try {
Path targetPath=this.fileStoreLocation.resolve(fileName);
Files.copy(file.getInputStream(),targetPath, StandardCopyOption.REPLACE_EXISTING);
return fileName;
}
catch (Exception e){
throw new FileStorageExecption("---------Cann't copy file----");
}
} }
----------this is my file controller----------
@RestController
public class FileController {
@Autowired
FileService fileService ;
@RequestMapping(method = RequestMethod.POST,value = "/file/upload")
public String fileUpload(@RequestParam MultipartFile file) throws FileStorageExecption {
fileService.storeFile(file);
return "ok";
}
}
--------------------so Failed to instantiate fileService with this error-------------------- Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled. 20-01-19 Sun 12:49:32.308 ERROR SpringApplication Application run failed org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'fileController': Unsatisfied dependency expressed through field 'fileService'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'fileService' defined in file [/media/hp/2FFE0BC66362754F/project/AndunaEchoMedia/target/classes/lk/andunaechomedia/service/FileService.class]: Bean instantiation via constructor failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [lk.andunaechomedia.service.FileService]: Constructor threw exception; nested exception is java.lang.NullPointerException at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:643) at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:116) at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:399) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1422) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:594) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:517) at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:323) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:321) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:879) at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:878) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:550) at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141) at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:747) at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226) at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215) at lk.andunaechomedia.Fire.main(Fire.java:10) Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'fileService' defined in file [/media/hp/2FFE0BC66362754F/project/AndunaEchoMedia/target/classes/lk/andunaechomedia/service/FileService.class]: Bean instantiation via constructor failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [lk.andunaechomedia.service.FileService]: Constructor threw exception; nested exception is java.lang.NullPointerException at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:314) at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:295) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1358) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1204) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:557) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:517) at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:323) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:321) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:276) at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1287) at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1207) at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:640) ... 19 common frames omitted Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [lk.andunaechomedia.service.FileService]: Constructor threw exception; nested exception is java.lang.NullPointerException at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:213) at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:117) at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:310) ... 32 common frames omitted Caused by: java.lang.NullPointerException: null at sun.nio.fs.UnixPath.normalizeAndCheck(UnixPath.java:77) at sun.nio.fs.UnixPath.(UnixPath.java:71) at sun.nio.fs.UnixFileSystem.getPath(UnixFileSystem.java:281) at java.nio.file.Paths.get(Paths.java:84) at lk.andunaechomedia.service.FileService.(FileService.java:22) at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) at java.lang.reflect.Constructor.newInstance(Constructor.java:423) at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:200) ... 34 common frames omitted
Process finished with exit code 1
# 1 楼答案
FileService的构造函数应该有FileStorageProperties而不是File