java - 后端与前端之间的文件(完整示例)

Question

我正在将文件 URL 传递到前端。问题是 url 仅对服务器可用 (settings.dockerIP())，因为用户没有连接到 docker。

所以我需要一种方法将我的 url 转换成一个文件，然后将它发送给所有在后端的用户..

我当前的代码是这样的(它可以工作，但用户需要一个到 docker 主机的隧道)

Controller

 @RequestMapping("/report")
public ModelAndView report(HttpServletRequest request) {
    String environmentName = request.getParameter("name");
    ModelAndView model = new ModelAndView("report");    
    model.addObject("file", Report.getFileFromContainer(environmentName));

    return model;
}

类

 public static String getFileFromContainer(String environmentName) {
    Container container = getContainerID(environmentName);
    String url = "";
    if(container != null) {
        Settings settings = Settings.getSettings();
        url = "http://" + settings.getDockerIP() + ":" + settings.getDockerPort() + "/containers/" + container.getId() + "/archive?path=/path/file";
    }
    return url;
}

前端

 <a href="${file}"></a>

Answer 1

您可以创建一个方法，将文件作为流返回，然后将最后一个的 url 分配给您的链接按钮，

@RequestMapping(value="getFile", method=RequestMethod.GET)
public void getFile(HttpServletResponse response,HttpServletRequest request) {
     String environmentName = request.getParameter("name");
    //here the code to get your file as stream 
    //whether getting the file by Ressource or buffred ,
    //here for example I named a getfileStream() method wihch return your file  InputStream
    InputStream myStream  = getFileStream(environmentName);


    // Set the content type and attachment header add filename and it's extention.
    response.addHeader("Content-disposition", "attachment;filename=myfile.myExtention");
    response.setContentType("txt/plain");

    // copy your file stream to Response 
    IOUtils.copy(myStream, response.getOutputStream());
    response.flushBuffer();
}

为了获取名称parameter，您只需将其传递给/report Controller 中的modelview，然后将其分配给您的关联 。

如下:

@RequestMapping("/report")
public ModelAndView report(HttpServletRequest request) {
    String environmentName = request.getParameter("name");
    ModelAndView model = new ModelAndView("report");    
    model.addObject("name", environmentName);

    return model;
}

那么你的链接会是这样的:

<a href="<c:url value="/getFile" />?name=${name}">Get file</a>

getFileStream 可能是这样的:

public InputStream getFileStream(String environmentName) {
    Container container = getContainerID(environmentName);
    String url = "";
    if(container != null) {
        Settings settings = Settings.getSettings();
        url = "http://" + settings.getDockerIP() + ":" + settings.getDockerPort() + "/containers/" + container.getId() + "/archive?path=/path/file";
    }
    InputStream is = new URL(url).openStream();

    return is; 
}

为了使用 IOUtils，您必须将以下 appace common io 添加到您的项目中

<dependency>
    <groupId>commons-io</groupId>
    <artifactId>commons-io</artifactId>
    <version>2.5</version>
</dependency>