java 如何通过接口的方式实现下载文件？

秒速五厘米 2024-02-17 09:29 97阅读 0赞

### 实现文件下载功能 ###

这里提供了下载的方法，希望能帮到你。

/**
         * 前端下载文件
         *
         * @param response
         * @param fileName 文件名称
         * @param filePath 文件路径
         */
        public static void download(HttpServletResponse response, String fileName, String filePath) throws Exception {
        
            BufferedOutputStream bos = null;
            InputStream content = null;
            FileInputStream fileInputStream = null;
            response.reset();
            try {
        
                response.setHeader("Access-Control-Allow-Origin", "*");
                response.setHeader("Access-Control-Allow-Methods", "*");
                response.setHeader("Access-Control-Max-Age", "3600");
                response.setHeader("Access-Control-Allow-Headers", "*");
                response.setHeader("Content-Disposition", "attachment;filename="
                        + URLEncoder.encode(fileName, "UTF-8"));
                response.setContentType("application/x-download;charset=UTF-8");
    
                HttpGet http = new HttpGet(filePath);
                CloseableHttpClient httpClient = HttpClients.custom().build();
                CloseableHttpResponse closeableHttpResponse = httpClient.execute(http);
    
                //获取响应HttpEntity对象
                HttpEntity httpEntity = closeableHttpResponse.getEntity();
                response.setHeader("Content-Length", String.valueOf(httpEntity.getContentLength()));
                content = httpEntity.getContent();
                File tempFile = File.createTempFile("byteFile", null);
                FileCopyUtils.copy(StreamUtils.copyToByteArray(content), tempFile);
                fileInputStream = new FileInputStream(tempFile);
    
                bos = new BufferedOutputStream(response.getOutputStream());
                byte[] buff = new byte[2048];
                int bytesRead;
                while (-1 != (bytesRead = fileInputStream.read(buff, 0, buff.length))) {
        
                    bos.write(buff, 0, bytesRead);
                }
            } finally {
        
                if (content != null) {
        
                    content.close();
                }
                if (fileInputStream != null) {
        
                    fileInputStream.close();
                }
                if (bos != null) {
        
                    bos.close();
                }
            }
        }