问题备忘: 将工程打包成jar包运行,就报java.io.FileNotFoundException: class path resource错误

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最近在在使用@Value注入文件碰到如下问题: 工程在在IntelliJ IDEA开发环境里正常运行,但是一旦将工程打包成jar包运行,就报java.io.FileNotFoundException: class path resource错

代码如下:通过@Value将resource目录下test/billingconfig-file.xml目录注入到Resource上

@Value("classpath:test/billingconfig-file.xml")
private Resource resourceFile; // 注入计费点文件资源

JAXBContext context = JAXBContext.newInstance(BillingModelList.class);
Unmarshaller unmarshaller = context.createUnmarshaller();
BillingModelList billingModelList = (BillingModelList) unmarshaller.unmarshal(resourceFile.getFile());

代码在IntelliJ IDEA开发环境里正常运行,但是一旦将工程打包成jar包运行,就提示如下错误:

java.io.FileNotFoundException: class path resource [test/billingconfig-file.xml] cannot be resolved to absolute file path because it does not reside in the file system: jar:file:/C:/Users/Administrator/Desktop/tmp/other/sp-bap-simulator-1.5.17.RELEASE.jar!/BOOT-INF/classes!/test/billingconfig-file.xml
	at org.springframework.util.ResourceUtils.getFile(ResourceUtils.java:215)
	at org.springframework.core.io.AbstractFileResolvingResource.getFile(AbstractFileResolvingResource.java:52)
	at im.yixin.spbap.logic.support.PayContext.init(PayContext.java:63)
	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:497)
	at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleElement.invoke(InitDestroyAnnotationBeanPostProcessor.java:366)
	at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleMetadata.invokeInitMethods(InitDestroyAnnotationBeanPostProcessor.java:311)

原因是因为unmarshaller.unmarshal传入的参数是File, 在IntelliJ IDEA里运行时,billingconfig-file.xml是个独立的文件,可以被File访问到, 但是将工程打包成jar包运行,billingconfig-file.xml被封装到jar包中了,不是一个独立文件了,此时肯定无法使用File访问到。 了解了原因,我们可以将传递unmarshaller.unmarshal()方法的参数从File变成InputStream就可以了

将
unmarshaller.unmarshal(resourceFile.getFile());
修改为:
unmarshaller.unmarshal(resourceFile.getInputStream());

完整代码如下:

@Value("classpath:test/billingconfig-file.xml")
private Resource resourceFile; // 注入计费点文件资源

JAXBContext context = JAXBContext.newInstance(BillingModelList.class);
Unmarshaller unmarshaller = context.createUnmarshaller();
BillingModelList billingModelList = (BillingModelList) unmarshaller.unmarshal(resourceFile.getInputStream())