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")
public JSONData downloadTemplateFile(HttpServletResponse response) {
String filePath = "templateFile/test.xlsx";
Resource resource = new ClassPathResource(filePath);//用来读取resources下的文件
InputStream is = null;
BufferedInputStream bis = null;
OutputStream os = null;
try {
File file = resource.getFile();
if (!file.exists()) {
return new JSONData(false,"模板文件不存在");
}
is = new FileInputStream(file);
os = response.getOutputStream();
bis = new BufferedInputStream(is);
//设置响应头信息
response.setCharacterEncoding("UTF-8");
this.response.setContentType("application/octet-stream; charset=UTF-8");
StringBuffer contentDisposition = new StringBuffer("attachment; filename=\"");
String fileName = new String(file.getName().getBytes(), "utf-8");
contentDisposition.append(fileName).append("\"");
this.response.setHeader("Content-disposition", contentDisposition.toString());
//边读边写
byte[] buffer = new byte[500];
int i;
while ((i = bis.read(buffer)) != -1) {
os.write(buffer, 0, i);
}
os.flush();
} catch (FileNotFoundException e) {
e.printStackTrace();
return new JSONData(false,"模板文件不存在");
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
if(os != null) os.close();
if(bis != null) bis.close();
if(is != null) is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return new JSONData("模板文件下载成功");
}
高高兴兴的启动项目后发现还是找不到文件，错误日志：
java.io.FileNotFoundException: class path resource [templateFile/test.xlsx] cannot be resolved to URL because it does not exist
at org.springframework.core.io.ClassPathResource.getURL(ClassPathResource.java:195)
at org.springframework.core.io.AbstractFileResolvingResource.getFile(AbstractFileResolvingResource.java:129)
at com.citycloud.parking.support.controller.operate.OperateBusinessUserController.downloadTemplateFile(OperateBusinessUserController.java:215)
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:498)
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:209)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:136)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:102)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:877)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:783)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:991)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:974)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:877)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:661)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:851)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.filterAndRecordMetrics(WebMvcMetricsFilter.java:158)
at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.filterAndRecordMetrics(WebMvcMetricsFilter.java:126)
at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.doFilterInternal(WebMvcMetricsFilter.java:111)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
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 “target\classes”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：springboot的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：
<build>
<resources>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/*.properties</include>
<include>**/*.xml</include>
</includes>
<!--是否替换资源中的属性-->
<filtering>false</filtering>
</resource>
<resource>
<directory>src/main/resources</directory>
<includes>
<include>**/*.properties</include>
<include>**/*.xml</include>
<include>**/*.yml</include>
<include>**/Dockerfile</include>
<include>**/*.xlsx</include>
</includes>
<!--是否替换资源中的属性-->
<filtering>false</filtering>
</resource>
</resources>
</build>
重新启动，再到classPath下看，发现有了这个文件了，同时也能获取了。如果文件名为中文的话就会出现乱码的情况。
- 怎么解决文件名中文乱码？
Access-Control-Allow-Origin →*
Access-Control-Allow-Credentials →true
Access-Control-Allow-Headers →accessToken,Access-Control-Allow-Origin,Content-Type,X-Requested-With,accept,Origin,Access-Control-Request-Method,Access-Control-Request-Headers
Access-Control-Allow-Methods →POST,GET,PUT,PATCH,DELETE,OPTIONS,HEAD
Access-Control-Max-Age →360
Content-disposition →attachment; filename="????????-??????????.xlsx"
Content-Type →application/octet-stream;charset=UTF-8
Transfer-Encoding →chunked
Date →Fri, 19 Apr 2019 06:47:34 GMT
上面是使用postman测试中文乱码response响应头相关信息。
后面怎么改都乱码，然后我就试着到浏览器中请求试试，结果发现只是postman的原因，只要文件名编码跟返回内容编码一致（"Content-disposition"和“ContentType”）就行：
this.response.setContentType("application/octet-stream; charset=iso-8859-1");
StringBuffer contentDisposition = new StringBuffer("attachment; filename=\"");
String fileName = file.getName();
contentDisposition.append(fileName).append("\"");
//设置文件名编码
String contentDispositionStr = new String(contentDisposition.toString().getBytes(), "iso-8859-1");
this.response.setHeader("Content-disposition", contentDispositionStr);
到此全部结束！