spring - mvc file download(파일 다운로드)

Downloading file from model and view in spring

0down votefavorite 2

i'm trying to create a page where users can download some .log file. this is the code : if(action.equalsIgnoreCase("download")){ String file = (String)request.getParameter("file"); response.setHeader("Content-Disposition", "attachment;filename="+file+""); response.setContentType("text/plain"); File down_file = new File("log/"+file); FileInputStream fileIn = new FileInputStream(down_file); ServletOutputStream out = response.getOutputStream(); byte[] outputByte = new byte[4096]; //copy binary contect to output stream while(fileIn.read(outputByte, 0, 4096) != -1) { out.write(outputByte, 0, 4096); } fileIn.close(); out.flush(); out.close(); return null; } where am i doing wrong ? when i click on the download button it correctly ask me to save the file, but it is always a 0 byte file... java spring spring-mvc file-download share|improve this question edited Aug 1 '12 at 16:20 davioooh 2,79021042 asked Aug 1 '12 at 15:47 Medioman92 2817

1   Does down_file.canRead() return true? – Xaerxess Aug 1 '12 at 16:01 yes, it returns true – Medioman92 Aug 1 '12 at 16:09

2 Answers

activeoldestvotes

up vote1down voteaccepted

This should do the job: public void getFile(final HttpServletResponse response) { String file = (String) request.getParameter("file"); response.setHeader("Content-Disposition", "attachment;filename=" + file); response.setContentType("text/plain"); File down_file = new File("log/" + file); FileInputStream fileIn = new FileInputStream(down_file); ByteStreams.copy(fileIn, response.getOutputStream()); response.flushBuffer(); return null; } where ByteStreams.copy comes from wonderful Google's Guava library. EDIT: Also, if you are using Spring MVC 3.1 you can do it in cleaner way (that's how I do it, turns out to be one-liner ;)): @Controller public final class TestController extends BaseController { @RequestMapping(value = "/some/url/for/downloading/files/{file}", produces = "text/plain") @ResponseBody public byte[] getFile(@PathVariable final String file) throws IOException { return Files.toByteArray(new File("log/" + file)); } } and in your servlet.xml add converter to mvc:message-converters: <mvc:annotation-driven> <mvc:message-converters> <bean class="org.springframework.http.converter.ByteArrayHttpMessageConverter" /> </mvc:message-converters> </mvc:annotation-driven> so that you can return byte[] from any @Controller method annotated with @ResponseBody. Read more here and here. Files.toByteArray is also from Guava. share|improve this answer edited Aug 1 '12 at 16:38 answered Aug 1 '12 at 16:20 Xaerxess 7,46021540

i have another problem, i tried your code, but i'm still getting a NoClassDefFoundError relative to guava despite i have added the jar in the class path. P.S. the error come out only at running time, the java file doesn't notice any problem. Sorry for my bad english – Medioman92 Aug 2 '12 at 8:05 i solved class path problem, but anyway i'mm still getting 0 byte files when try to download – Medioman92Aug 2 '12 at 8:13 i've found where the problem is, File down_file = new File("log/" + file); with absolute path it works, with relative path it doesn't work, WHY ? – Medioman92 Aug 2 '12 at 8:39 What path does new File(".").getCanonicalPath() return? – Xaerxess Aug 2 '12 at 9:07 C:\Program Files\Apache Software Foundation\Tomcat 5.5\bin i solved using getServletContext().getRealPath("log")+file thanks – Medioman92 Aug 2 '12 at 9:32

up vote2down vote	Try with: IOUtils.copy(fileIn, response.getOutputStream()); response.flushBuffer(); you can find Apache Commons IO here: http://commons.apache.org/io/ Here you find IOUtils.copy() reference. share|improve this answer answered Aug 1 '12 at 16:12 davioooh 2,79021042
	Thanx, this helped me as well. Although I've used Spring's FileCopyUtils to achieve the same – GileB Jan 25 at 11:45 @GileB glad to help :) – davioooh Jan 25 at 14:12

출처 - http://stackoverflow.com/questions/11762934/downloading-file-from-model-and-view-in-spring