使用 java 在基于 REST 的 web 服务中响应文件
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File response in REST based webservice using java
提问by user1332962
I am writing a REST webserivce using spring. I have to return back a file in the response.
我正在使用 spring 编写 REST webserivce。我必须在响应中返回一个文件。
Its a GET call and when the user enters the URL, the user should be shown with the download section in the browser.
它是一个 GET 调用，当用户输入 URL 时，应该会在浏览器中向用户显示下载部分。
I am not sure what should be the return type in the controller. Do i have to specify any content type i code?
我不确定控制器中的返回类型应该是什么。我是否必须指定我编码的任何内容类型？
采纳答案by user1332962
I used the below piece of code
我使用了下面的一段代码
FileInputStream inputStream = new FileInputStream("FileInputStreamDemo.java"); //read the file
response.setHeader("Content-Disposition","attachment; filename=test.txt");
try {
int c;
while ((c = inputStream.read()) != -1) {
response.getWriter().write(c);
}
} finally {
if (inputStream != null)
inputStream.close();
response.getWriter().close();
}
This was found in one more thread
这是在另一个线程中找到的
how to write a file object on server response and without saving file on server?
回答by Anand
I had the similar requirement in my project. I used the below piece of code
我在我的项目中有类似的要求。我使用了下面的一段代码
@Controller
@RequestMapping("/reports")
public class ReportsController {
protected static String PRODUCTIVITY_REPORT_FILE = "productivityReportFile";
@Resource(name="propertyMap")
protected Map<String, String> propertyMap;
@RequestMapping(value="/cratl/productivity_report", method=RequestMethod.GET, produces="application/vnd.openxmlformats-officedocument.spreadsheetml.sheet")
public @ResponseBody byte[] getProductivityReport()
throws Exception {
byte[] reportBytes = null;
try {
File reportFile = new File(propertyMap.get(PRODUCTIVITY_REPORT_FILE));
if (reportFile != null && reportFile.exists()) {
InputStream reportInputStream = new FileInputStream(reportFile);
long length = reportFile.length();
reportBytes = new byte[(int)length];
int offset = 0;
int numRead = 0;
while (offset < reportBytes.length
&& (numRead = reportInputStream.read(reportBytes, offset, reportBytes.length-offset)) >= 0) {
offset += numRead;
}
if (offset < reportBytes.length) {
throw new Exception("Could not completely read file "+ reportFile.getName());
}
reportInputStream.close();
}
} catch (Exception e) {
e.printStackTrace();
}
return reportBytes;
}
I hope it helps you
我希望它能帮助你
回答by fonZ
Your controller method, which can have any name you want, returns a String with a url name that is defined in the views.xml that is defined for the view you want to load, the downloads section in this case. So your controller looks like this:
您的控制器方法（可以使用您想要的任何名称）返回一个字符串，该字符串带有在为您要加载的视图（在本例中为下载部分）定义的 views.xml 中定义的 url 名称。所以你的控制器看起来像这样：
@Controller
public class MyController {
@RequestMapping(value = "/downloads", method = RequestMethod.GET)
public String getDownloadSection() {
System.out.println("getting downloads");
return "downloads/index";
}
}
Your views.xml should contain the tag:
你的 views.xml 应该包含标签：
<definition extends="default" name="downloads/index">
<put-attribute name="body" value="/WEB-INF/views/downloads/index.jspx"/>
</definition>
The extends="default"is a tile definition that should be in your layouts.xml
该延伸=“默认”是一个平铺定义，应该是在你的layouts.xml
I think thats about it. If you do a GET request to //yoursite/downloads it should print the message.
我想就是这样。如果您对 //yoursite/downloads 发出 GET 请求，它应该打印该消息。
That should answer your question i hope :)
这应该能回答你的问题，我希望:)
