Question

我有一个spring boot API，它创建一个pdf报告并下载，如果我直接在浏览器中调用该API，则会直接创建并下载pdf，但是当我从Angular 6调用该GET API时，我得到以下信息错误：

Spring boot（java）代码：

@RequestMapping(value = "/app_report/en", method = RequestMethod.GET)
@ResponseBody
public void getEnRpt(HttpServletResponse response, @RequestParam("appNum") String appNum) throws JRException, IOException, SQLException {

    JasperReport jasperReport = JasperCompileManager.compileReport("./src/main/resources/jasperReports/App_created_en.jrxml");

    Connection connection = dataSource.getConnection();

    Map<String, Object> params = new HashMap<>();
    params.put("P_APP_NO", appNum);
    JasperPrint jasperPrint = JasperFillManager.fillReport(jasperReport, params, connection);

    response.setContentType("application/x-pdf");
    response.setHeader("Content-disposition", "inline; filename=App_report_en.pdf");

    final OutputStream outStream = response.getOutputStream();
    JasperExportManager.exportReportToPdfStream(jasperPrint, outStream);
}

调用API的Angular代码：（我尝试了多种方式，此处显示了两种）：

this.http.get(this.api_url + reportUrl, {
  responseType: 'blob'
}, ).subscribe((response: File) => {
  console.log('report is downloaded');
});

this.http.get(this.api_url + reportUrl).subscribe(
  (response) => {
    console.log('report is downloaded');
  });

Angular调用API后收到的控制台错误：

error:
SyntaxError: Unexpected token % in JSON at position 0 at JSON.parse (<anonymous>) at XMLHttpRequest.onLoad 
message: "Http failure during parsing for https://localhost:7001/reports/app_report/en?appNum=xxxxxxx"

name: "HttpErrorResponse"

ok: false

status: 200

statusText: "OK"

url: "https://localhost:7001/reports/app_report/en?appNum=xxxxxx"

我只需要像浏览器中那样调用API，这样就可以立即下载pdf

响应头如下：

Content-disposition 
inline; filename=App_report_en.pdf
Content-Type    
application/x-pdf

为什么Angular不像我调用该API那样在浏览器中下载文件？（特别是因为请求成功）

Answer 1

为避免JSON解析问题，您需要使用请求选项中的responseType: 'blob'告诉http客户端响应将是一个Blob。

然后，要使导航器真正打开文件，您可以按照this blog中的说明进行操作

    const fileName = "report.pdf";
    this.http.get(this.api_url + reportUrl, {  responseType: 'blob'})
    .subscribe((blob: Blob) => {
    console.log('report is downloaded');

    if (navigator.msSaveBlob) 
    { 
        // IE 10+
        navigator.msSaveBlob(blob, filename);
    }
    else 
    {
        let link = document.createElement("a");
        if (link.download !== undefined) 
        {
            let url = URL.createObjectURL(blob);
            link.setAttribute("href", url);
            link.setAttribute("download", fileName);
            link.style.visibility = 'hidden';
            document.body.appendChild(link);
            link.click();
            document.body.removeChild(link);
        }
        else
        {
            //html5 download not supported
        }
    }   
});

除了iO之外，这应该适用于IE 10+和其他现代浏览器（请参见CanIuse）

调用从Angular 6下载pdf的Spring引导api给出了错误，无法解析响应

1 个答案: