如何下载在我的服务器（springboot）上生成的angular pdf文件？

Question

“我想下载一个从基于spring的restful web服务发送的.pdf文件到我的angular应用程序。如何下载，我的angular应用程序或Spring Boot上是不是缺少了一些代码？”

我正在从angular 6应用程序向spring-boot服务器发送一个HTTP GET请求，该服务器生成一个.pdf文件，然后将这个.pdf文件作为blob发送给我，但当我试图在angular侧创建一个blob并打开pdf时，它显示以下错误：

.ERROR ERROR：请求体既不是blob也不是数组缓冲区

我访问了以下关于StackOverflow的问题，以找到一些解决方法：1。PDF Blob未显示内容，角度%2%2。如何在不将其转换为字符串或JSON的情况下访问Angular 2 http响应体？3.将HTTPResponse正文中的字节流转换为pdf文件4。用SpringBoot将文件发送到Angular2

在Angular App：Component：

 
getPDF(){
      this.apiService.getPDF(this.invoiceId)
      .subscribe(
        (data) => {
          //data.blob() doesnt work properly
          var file = new Blob([data.blob()], { type: 'application/pdf' })
          var fileURL = URL.createObjectURL(file);
          window.open(fileURL); // if you want to open it in new tab
          var a         = document.createElement('a');
          a.href        = fileURL; 
          a.target      = '_blank';
          a.download    = 'bill.pdf';
          document.body.appendChild(a);
          a.click();
        },
        (error) => {
          console.log('getPDF error: ',error);
        }
      );
    }

    getPDF(invoiceId : number)
         {
             this.url = this.main_url + '/invoices/generatepdf/'+invoiceId;
             const headers = new Headers({ 'Content-Type': 'application/json', 
             "Authorization": authorization, responseType : 'blob'});
             return this.http.get(this.url, { headers : headers})
                 .pipe(map(
                     (response) => {
                         return response;
                     },
                     (error) => {
                         console.log(error.json());
                     }
                 ));
         }

在Spring靴：
控制器：

    @RestController
    @RequestMapping("/invoices")
    public class InvoiceController {

    @Autowired
        InvoiceService invoiceService;

    @GetMapping(path = "/generatepdf/{invoiceId}")
        public void generateInvoicePdf(@PathVariable Integer invoiceId,
                HttpServletRequest request,HttpServletResponse response) {
            invoiceService.generateInvoicePdf(invoiceId, request, response);
    }


    @Override
        public String generateInvoicePdf(Integer invoiceId, HttpServletRequest request, HttpServletResponse response) {

             //createPDF() will create a .pdf file
            createPDF(pdfFilename, dto, dtoForSupplier);
            if (pdfFilename != null) {
                try {
                    File file = new File(pdfFilename);
                    FileInputStream is = new FileInputStream(file);
                    response.setContentType("application/blob");

                    // Response header
                    response.setHeader("Pragma", "public");
                    response.setHeader("responseType", "blob");
                    response.setHeader("Content-Disposition", "attachment; filename=\"" + pdfFilename + "\"");

                    // Read from the file and write into the response
                    OutputStream os = response.getOutputStream();
                    System.out.println(os);
                    byte[] buffer = new byte[(int) file.length()];

                    int len;
                    while ((len = is.read(buffer)) != -1) {
                        os.write(buffer, 0, len);
                    }

                    System.out.println(os);
                    os.flush();
                    os.close();
                    is.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            return pdfFilename;
        }

core.js:15724错误错误：请求正文既不是blob也不是数组缓冲区，位于response.push./node_modules/@angular/http/fesm5/http.js.body.blob(http.js:782)位于safeSubscriber._next(invoide-details.component.ts:212)位于safeSubscriber.push./node_modules/rxjs/_esm5/internal/subscriber.js.safeSubscriber.__tryRunsub(subscriber.js:196)位于One.js:423)>
                

Answer 1

按照@jbnizet的建议，我实现了如下可观察的：

组件：

getPDF(){
      this.apiService.getPDF(this.invoiceId)
      .subscribe(
        (data: Blob) => {
          var file = new Blob([data], { type: 'application/pdf' })
          var fileURL = URL.createObjectURL(file);

// if you want to open PDF in new tab
          window.open(fileURL); 
          var a         = document.createElement('a');
          a.href        = fileURL; 
          a.target      = '_blank';
          a.download    = 'bill.pdf';
          document.body.appendChild(a);
          a.click();
        },
        (error) => {
          console.log('getPDF error: ',error);
        }
      );
    }

服务：

getPDF(invoiceId : number): Observable<Blob>
     {
         this.url = this.main_url + '/invoices/generatepdf/'+invoiceId;
         var authorization = 'Bearer '+sessionStorage.getItem("access_token");

         const headers = new HttpHeaders({ 'Content-Type': 'application/json',
         "Authorization": authorization, responseType : 'blob'});

         return this.httpClient.get<Blob>(this.url, { headers : headers,responseType : 
         'blob' as 'json'});
     }

我引用的URL：

1. 重载#2:https://angular.io/api/common/http/httpclient#get
2. 使用Http post预览Blob:https://dzone.com/articles/how-to-preview-blobs-with-http-poster and-angular-5