创建httpclient 请求,并在header携带指定key,也可根据实际需要携带token等信息。获取第三方接口返回的文件输入流并写到本地response中,实现返回文件流,前端通过js的a标签进行下载。
代码如下:文章来源:https://www.toymoban.com/news/detail-588633.html
@Override
public void YKDownload(String fileId, HttpServletResponse response, HttpServletRequest request) {
logger.info("下载盈科附件, 参数:附件id = " + fileId);
// 创建默认的httpClient实例.
CloseableHttpClient httpclient = HttpClients.createDefault();
// 创建httpGet
HttpGet httpGet = new HttpGet("xxxxx" + fileId);
try {
// 设置请求头参数
httpGet.setHeader("xxxx-Key", "xxxxxx");
CloseableHttpResponse httpResponse = httpclient.execute(httpGet);
// 获取第三方接口放在Response中的文件名
Header[] headers = httpResponse.getHeaders("content-disposition");
if (headers != null && headers.length > 0) {
String contentDispositionValue = headers[0].getValue();
// 设置文件名,这里没用加密文件名,可以自己设置
response.addHeader("Content-Disposition", contentDispositionValue);
}
response.setContentType("application/octet-stream;charset=utf-8");
HttpEntity entity = httpResponse.getEntity();
InputStream inputStream = entity.getContent(); //获取输入流
// 保存流 从这里到重置游标
// 附件第一次下载没问题再下载有时候就报错,然后参照其他博主的方法,将流先保存下来
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());
// 第一次读流
StringBuffer out = new StringBuffer();
byte[] b1 = new byte[1024];
for (int n; (n = inputStream.read(b1)) != -1;) {
out.append(new String(b1, 0, n)); //这个可以用来读取文件内容 并且文件内容有中文读取出来也不会乱码
}
// 判断文件是否存在
String resultHtml = out.toString();
int firstIndex = resultHtml.indexOf("\n");
if(firstIndex < 0){
logger.info("文件不存在或异常"+resultHtml);
}
// 重置游标
inputStream.reset();
// 输出文件
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("下载盈科附件, 原因:" + e.getMessage());
e.printStackTrace();
} finally {
try {
httpclient.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
前端js代码文章来源地址https://www.toymoban.com/news/detail-588633.html
function fileYKDownload(fileId, fileName) {
//创建XMLHttpRequest对象
var httpRequest = new XMLHttpRequest();
//打开连接,将请求参数拼在url后面
httpRequest.open('GET', __baseUrl + '/v3/query/accessories/download?fileId=' + fileId, true);
//设置期望的返回值类型
httpRequest.responseType = "blob";
//设置请求头,将认证信息放入请求头中
httpRequest.setRequestHeader("PRIVATETOKEN",$.getCookie(__token));
//请求成功回调函数
httpRequest.onload = function (oEvent) {
if (httpRequest.status === 200) {
// 这里文件名可以从response中获取,为了方便我直接js方法传的文件名
// var fileName = decodeURI(httpRequest.getResponseHeader("Content-Disposition"));
console.log(fileName);
var response = httpRequest.response;
//数据转换为文件下载
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);
}
}
//发送请求
httpRequest.send();
}
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