文件下载 浏览器直接打开文件而不是保存 相关问题

昨天做SpringMVC 文件上传下载功能时遇到一堆问题。其中有个问题就是txt css js html xml pdf 等等文件下载时浏览器（html5的a标签download属性不是所有浏览器都支持的）是直接打开,而不是下载保存。网上有许多解决的方法，我这边只是整合下，做个mark。

场景就是有个url，老大提醒说用后台访问url获取文件流 前台来处理。。大概这个流程 代码如下：

前端js部分，参考http://www.alloyteam.com/2014/01/use-js-file-download/

//得到拼接字符串
function getFJInfo(name, url) {
return "<tr><td style=''><a  href='javascript:void(0)' onclick='getDownFile(\"" + url + "\",\"" + name + "\")'>" + name + "</a></td></tr>"
}
//文件下载
function getDownFile(url, name) {
var param = {
"url": url
};
$.ajax({
url: contextPath + '/product-label/file2Stream',
type: 'GET',
data: Base64.encode(JSON.encode(param)),
dataType: "text",
success: function(data) {
downloadFile(name, data)
}
})
}
//流处理触发下载事件
function downloadFile(fileName, content) {
var aLink = document.createElement('a');
var blob = new Blob([content]);
var evt = document.createEvent("MouseEvents");
evt.initMouseEvent("click", true, false, window, 0, 0, 0, 0, 0, false, false, false, false, 0, null);
aLink.download = fileName;
aLink.href = URL.createObjectURL(blob);
aLink.dispatchEvent(evt)
}

后台controller处理，参考http://blog.sina.com.cn/s/blog_87216a0001014sm7.html

/**
* 返回流
*
* @param requestMap 请求参数
* @param response 返回对象
*/
@RequestMapping(value = "/file2Stream", method = RequestMethod.GET)
public void file2Stream(@Json Map<String, Object> requestMap, HttpServletResponse response) {
try {
String url = String.valueOf(requestMap.get("url"));
// URL url =new URL(String.valueOf(requestMap.get("url")));
InputStream iStream = getFileStream(url);
OutputStream stream = response.getOutputStream();
stream.write(StreamUtils.getBytes(iStream));
stream.flush();
stream.close();
} catch (Exception e) {
LOG.error("ProductSalesRecommendController.file2Stream error | ({})", e);
}
}

/**
* HttpURLConnection获取网络路径的文件流
*
* @param url 链接
* @return InputStream
* @throws IOException
*/
private InputStream getFileStream(URL url) throws IOException {
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setConnectTimeout(5 * 1000);
conn.setRequestMethod("GET");
InputStream inStream = conn.getInputStream();
return inStream;
}

/**
* HttpClient获取网络路径的文件流
*
* @param url 链接字符串
* @return InputStream
* @throws IllegalStateException
* @throws IOException
*/
private InputStream getFileStream(String url) throws IllegalStateException, IOException {
HttpParams httpParams = new BasicHttpParams();
HttpConnectionParams.setConnectionTimeout(httpParams, 5000); // 设置连接超时为5秒
HttpClient client = new DefaultHttpClient(httpParams); // 生成一个http客户端发送请求对象
HttpResponse httpResponse = client.execute(new HttpGet(url)); // 发送请求并等待响应
HttpEntity entity = httpResponse.getEntity(); // 获取响应里面的内容
InputStream inStream = entity.getContent();
return inStream;
}

先这样吧。。老大说还有更高大上的。过段时间再看看