简介  这篇文章主要介绍了springboot-项目获取resources下文件碰到的问题（classPath下找不到文件和文件名乱码）以及相关的经验技巧，文章约17681字，浏览量498，点赞数7，值得推荐！

项目是spring-boot + spring-cloud 并使用maven 管理依赖。在springboot+maven项目下怎么读取resources下的文件实现文件下载？

• 怎么获取resources目录下的文件？（相对路径）

方法一：

File sourceFile = ResourceUtils.getFile("classpath:templateFile/test.xlsx"); //这种方法在linux下无法工作

方法二：

Resource resource = new ClassPathResource("templateFile/test.xlsx"); File sourceFile = resource.getFile();

我使用的是第二种。

 @PostMapping("/downloadTemplateFile")
 2     public JSONData downloadTemplateFile(HttpServletResponse response) {
 3         String filePath = "templateFile/test.xlsx";
 4         Resource resource = new ClassPathResource(filePath);//用来读取resources下的文件
 5         InputStream is = null;
 6         BufferedInputStream bis = null;
 7         OutputStream os = null;
 8         try {
 9             File file = resource.getFile();
10             if (!file.exists()) {
11                 return new JSONData(false,"模板文件不存在");
12             }
13             is = new FileInputStream(file);
14             os = response.getOutputStream();
15             bis = new BufferedInputStream(is);
16             //设置响应头信息
17             response.setCharacterEncoding("UTF-8");
18             this.response.setContentType("application/octet-stream; charset=UTF-8");
19             StringBuffer contentDisposition = new StringBuffer("attachment; filename="");
20             String fileName = new String(file.getName().getBytes(), "utf-8");
21             contentDisposition.append(fileName).append(""");
22             this.response.setHeader("Content-disposition", contentDisposition.toString());
23             //边读边写
24             byte[] buffer = new byte[500];
25             int i;
26             while ((i = bis.read(buffer)) != -1) {
27                 os.write(buffer, 0, i);
28             }
29             os.flush();
30         } catch (FileNotFoundException e) {
31             e.printStackTrace();
32             return new JSONData(false,"模板文件不存在");
33         } catch (IOException e) {
34             e.printStackTrace();
35         } finally {
36             try {
37                 if(os != null) os.close();
38                 if(bis != null) bis.close();
39                 if(is != null) is.close();
40             } catch (IOException e) {
41                 e.printStackTrace();
42             }
43         }
44         return new JSONData("模板文件下载成功");
45     }

高高兴兴的启动项目后发现还是找不到文件，错误日志：

 1 java.io.FileNotFoundException: class path resource [templateFile/test.xlsx] cannot be resolved to URL because it does not exist
 2     at org.springframework.core.io.ClassPathResource.getURL(ClassPathResource.java:195)
 3     at org.springframework.core.io.AbstractFileResolvingResource.getFile(AbstractFileResolvingResource.java:129)
 4     at com.citycloud.parking.support.controller.operate.OperateBusinessUserController.downloadTemplateFile(OperateBusinessUserController.java:215)
 5     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 6     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
 7     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
 8     at java.lang.reflect.Method.invoke(Method.java:498)
 9     at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:209)
10     at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136)
11     at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102)
12     at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:877)
13     at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:783)
14     at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
15     at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991)
16     at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925)
17     at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:974)
18     at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:877)
19     at javax.servlet.http.HttpServlet.service(HttpServlet.java:661)
20     at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:851)
21     at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
22     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
23     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
24     at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
25     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
26     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
27     at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.filterAndRecordMetrics(WebMvcMetricsFilter.java:158)
28     at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.filterAndRecordMetrics(WebMvcMetricsFilter.java:126)
29     at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.doFilterInternal(WebMvcMetricsFilter.java:111)
30     at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
31     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)

因为我知道Resource resource = new ClassPathResource("templateFile/test.xlsx");就是到classPath*（注意这里有个*）下去找，然后就去项目本地的目录下找classPath下是否有这个文件（maven的classPath在 “targetclasses”目录下），就发现并没有这个文件在。

后面仔细想想这是Maven项目啊，所以就找pom.xml文件去看看，突然想起：maven默认只会加载classPath同级目录下文件（配置那些），其他的需要配置<resources>标签：

 1 <build>
 2   <resources>
 3       <resource>
 4         <directory>src/main/java</directory>
 5         <includes>
 6           <include>**/*.properties</include>
 7           <include>**/*.xml</include>
 8         </includes>
 9         <!--是否替换资源中的属性-->
10         <filtering>false</filtering>
11       </resource>
12       <resource>
13         <directory>src/main/resources</directory>
14         <includes>
15           <include>**/*.properties</include>
16           <include>**/*.xml</include>
17           <include>**/*.yml</include>
18           <include>**/Dockerfile</include>
19           <include>**/*.xlsx</include>
20         </includes>
21         <!--是否替换资源中的属性-->
22         <filtering>false</filtering>
23       </resource>
24   </resources>
25 </build>