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Java把文件链接转成流，返回给前端下载

news 2025/8/26 20:29:29

背景：已知Java拿到了一个PDF链接（http://xxx.xxx.pdf），直接把链接返给前端的话，前端是不能点击直接下载的，需要后端先把url转成文件流，再由前端下载，处理如下：
导入pom：

        <dependency><groupId>org.apache.pdfbox</groupId><artifactId>pdfbox</artifactId><version>2.0.24</version></dependency>

接口部分：

    @GetMapping("/downloadPdf")public void downloadPdf(@RequestParam String patentId, HttpServletResponse response) throws IOException {String pdfLink = "http://xxx.xxx.pdf";URL url = new URL(pdfLink);try (InputStream inputStream = url.openStream();PDDocument document = PDDocument.load(inputStream)) {// 设置响应头response.setContentType("application/pdf");response.setHeader("Content-Disposition", "attachment;");// 写入响应流try (OutputStream outputStream = response.getOutputStream()) {document.save(outputStream);}}}

前端部分：

    downloadPDF() {let url = baseURL + "/xxx/xxx/downloadPdf?patentId=" + this.patent_id; // 对应后端接口console.log(url);axios({method: 'get',url: url,responseType: 'blob',	// 不加的话会白页headers: {'Authorization': 'Bearer ' + getToken()}}).then(response => {const blob = new Blob([response.data]);const url = URL.createObjectURL(blob);const link = document.createElement('a');link.href = url;link.download = `xxx.pdf`;	// 下载的文件名字link.click();});}