如何使用 Java Springboot 返回 zip 文件流 [英] How to return a zip file stream using Java Springboot

问题描述

我用的是 Springboot，我想生成 zip 文件然后返回前端.

I use Springboot, I want to generate zip file and then return to frontend.

@PostMapping(value="/export", produces = MediaType.APPLICATION_OCTET_STREAM_VALUE)
public ResponseEntity<ZipOutputStream> export() {
    // customService.generateZipStream() is a service method that can 
    //generate zip file using ZipOutputStream and then return this stream
    ZipOutputStream zipOut = customService.generateZipStream();
    return ResponseEntity
                  .ok()
                  .header("Content-Disposition", "attachment;filename=export.zip")
                  .header("Content-Type","application/octet-stream")
                  .body(zipOut)
}

可以正确生成 zip 文件(在本地目录中)，但在将流返回到前端时出现以下错误:

The zip file can be generated correctly(in local dir) but I got below error when return stream to frontend:

spring.HttpMediaTypeNotAcceptableException: Could not find acceptable representation

然后我检查了谷歌并将返回类型更改为ResponseEntity<StreamResponseBody>，但是我应该如何在方法ZipOutputStream 到StreamResponseBodycode>body(...)，google 中的解决方案是在 body() 方法中创建 zip 输出流，如下所示:

Then i checked in google and changed return type to ResponseEntity<StreamResponseBody>, but how should I change ZipOutputStream to StreamResponseBody in method body(...), the solution in google is create zip output stream within body() method like that:

   // pseudocode
   .body(out -> { 
                   ZipOutputStream zipOut = new ZipOutputStream(out));
                   zipOut.putEntry(...);
                   zipOut.write(...);
                   zipOut.closeEntry();
                   ... balabala
                }

我的问题是如何在这种情况下使用 StreamResponseBody或任何替代解决方案来返回可能有点大的 zip 流.

My question is how to use StreamResponseBody in this scenario or any alternative solution to return a zip stream that might a little large.

推荐答案

感谢大家的帮助，我检查了你的答案并通过更新导出逻辑解决了这个问题.

Thanks for everyone's help, I checked yours answers and solved this issue by updating export logic.

我的解决方案:

将方法重新定义为 customService.generateZipStream(ZipOutputStream zipOut) 以便我可以在 controller 层和​​ StreamResponseBody 中创建一个压缩流然后将其发送到服务层，在服务层，我将进行导出.

Re-define method as customService.generateZipStream(ZipOutputStream zipOut)so that I can create a zip stream with StreamResponseBody in controller layer and then send it to service layer, in service layer, i will do export.

伪代码如下:

@PostMapping(value="/export", produces = MediaType.APPLICATION_OCTET_STREAM_VALUE)
public ResponseEntity< StreamResponseBody > export() {
    // customService.generateZipStream() is a service method that can 
    //generate zip file using ZipOutputStream and then return this stream
    
    return ResponseEntity
                  .ok()
                  .header("Content-Disposition", "attachment;filename=export.zip")
                  .body(outputStream -> {
                     // Use inner implement and set StreamResponseBody to ZipOutputStream
                     try(ZipOutputStream zipOut = new ZipOutputStream(outputStream)) {
                         customService.generateZipStream(zipOut);
                     }
                  });
}

customService 前置代码:

public void generateZipStream(ZipOutputStream zipOut) {
    // ... do export here
    zipOut.putEntry(...);
    zipOut.write(...);
    zipOut.closeEntry();
    // ... balabala

}

希望如果您有类似的问题，它可以帮助您.

Hope it can help you if you have similar question.

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