創(chuàng)建httpclient 請(qǐng)求，并在header攜帶指定key，也可根據(jù)實(shí)際需要攜帶token等信息。獲取第三方接口返回的文件輸入流并寫到本地response中，實(shí)現(xiàn)返回文件流，前端通過js的a標(biāo)簽進(jìn)行下載。

代碼如下：

@Override
    public void YKDownload(String fileId, HttpServletResponse response, HttpServletRequest request) {
        logger.info("下載盈科附件， 參數(shù)：附件id = " + fileId);
        // 創(chuàng)建默認(rèn)的httpClient實(shí)例.
        CloseableHttpClient httpclient = HttpClients.createDefault();
        // 創(chuàng)建httpGet
        HttpGet httpGet = new HttpGet("xxxxx" + fileId);
        try {
			// 設(shè)置請(qǐng)求頭參數(shù)
            httpGet.setHeader("xxxx-Key", "xxxxxx");
            CloseableHttpResponse httpResponse = httpclient.execute(httpGet);
			// 獲取第三方接口放在Response中的文件名
            Header[] headers = httpResponse.getHeaders("content-disposition");
            if (headers != null && headers.length > 0) {
                String contentDispositionValue = headers[0].getValue();
				// 設(shè)置文件名，這里沒用加密文件名，可以自己設(shè)置
                response.addHeader("Content-Disposition", contentDispositionValue);
            }
            response.setContentType("application/octet-stream;charset=utf-8");
            HttpEntity entity = httpResponse.getEntity();
            InputStream inputStream = entity.getContent(); //獲取輸入流
			
            //  保存流 從這里到重置游標(biāo)
			//  附件第一次下載沒問題再下載有時(shí)候就報(bào)錯(cuò)，然后參照其他博主的方法，將流先保存下來
            ByteArrayOutputStream bos = new ByteArrayOutputStream();
            BufferedInputStream br = new BufferedInputStream(inputStream);
            byte[] b = new byte[1024];
            for (int c = 0; (c = br.read(b)) != -1;)
            {
                bos.write(b, 0, c);
            }
            b = null;
            br.close();
            inputStream = new ByteArrayInputStream(bos.toByteArray());
            // 第一次讀流
            StringBuffer out = new StringBuffer();
            byte[] b1 = new byte[1024];
            for (int n; (n = inputStream.read(b1)) != -1;) {
                out.append(new String(b1, 0, n));  //這個(gè)可以用來讀取文件內(nèi)容 并且文件內(nèi)容有中文讀取出來也不會(huì)亂碼
            }
            // 判斷文件是否存在
            String resultHtml = out.toString();
            int firstIndex = resultHtml.indexOf("\n");
            if(firstIndex < 0){
                logger.info("文件不存在或異常"+resultHtml);
            }
            // 重置游標(biāo)
            inputStream.reset();


            // 輸出文件
            ServletOutputStream outputStream = response.getOutputStream();
            try {
                byte[] oBuff = new byte[1024];
                int iSize;
                while (-1 != (iSize = inputStream.read(oBuff))) {
                    outputStream.write(oBuff, 0, iSize);
                }
                outputStream.flush();
            } finally {
                IOUtils.close(outputStream);
                IOUtils.close(inputStream);
            }
            outputStream.close();
        } catch (Exception e) {
            logger.info("下載盈科附件， 原因：" + e.getMessage());
            e.printStackTrace();
        } finally {
            try {
                httpclient.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

前端js代碼文章來源地址http://www.zghlxwxcb.cn/news/detail-588633.html

function fileYKDownload(fileId, fileName) {
    //創(chuàng)建XMLHttpRequest對(duì)象
    var httpRequest = new XMLHttpRequest();
    //打開連接，將請(qǐng)求參數(shù)拼在url后面
    httpRequest.open('GET', __baseUrl + '/v3/query/accessories/download?fileId=' + fileId, true);
    //設(shè)置期望的返回值類型
    httpRequest.responseType = "blob";
    //設(shè)置請(qǐng)求頭，將認(rèn)證信息放入請(qǐng)求頭中
    httpRequest.setRequestHeader("PRIVATETOKEN",$.getCookie(__token));

    //請(qǐng)求成功回調(diào)函數(shù)
    httpRequest.onload = function (oEvent) {
        if (httpRequest.status === 200) {
			// 這里文件名可以從response中獲取，為了方便我直接js方法傳的文件名
            // var fileName = decodeURI(httpRequest.getResponseHeader("Content-Disposition"));
            console.log(fileName);
            var response = httpRequest.response;

            //數(shù)據(jù)轉(zhuǎn)換為文件下載
            var elink = document.createElement('a');
            elink.download = fileName;
            elink.style.display = 'none';
            var blob = new Blob([response]);
            elink.href = URL.createObjectURL(blob);
            document.body.appendChild(elink);
            elink.click();
            document.body.removeChild(elink);
        }
    }
    //發(fā)送請(qǐng)求
    httpRequest.send();
}

到了這里，關(guān)于java通過httpclient攜帶請(qǐng)求頭參數(shù)獲取第三方文件流接口并實(shí)現(xiàn)實(shí)現(xiàn)文件下載的文章就介紹完了。如果您還想了解更多內(nèi)容，請(qǐng)?jiān)谟疑辖撬阉鱐OY模板網(wǎng)以前的文章或繼續(xù)瀏覽下面的相關(guān)文章，希望大家以后多多支持TOY模板網(wǎng)！