前端网站做中 英文怎么说/女生做sem专员的工作难吗

如果你要是想从字符串是截取那就是想找找 最后一个. 在哪个地方，然后再再去找 . 后面的字符，但Android提供了一个方法可以直接获取。

android.webkit 包中

String ext = MimeTypeMap.getFileExtensionFromUrl(String url);

原代码是这样的：

 /*** Returns the file extension or an empty string iff there is no* extension. This method is a convenience method for obtaining the* extension of a url and has undefined results for other Strings.* @param url* @return The file extension of the given url.*/public static String getFileExtensionFromUrl(String url) {if (!TextUtils.isEmpty(url)) {int fragment = url.lastIndexOf('#');if (fragment > 0) {url = url.substring(0, fragment);}int query = url.lastIndexOf('?');if (query > 0) {url = url.substring(0, query);}int filenamePos = url.lastIndexOf('/');String filename =0 <= filenamePos ? url.substring(filenamePos + 1) : url;// if the filename contains special characters, we don't// consider it valid for our matching purposes:if (!filename.isEmpty() &&Pattern.matches("[a-zA-Z_0-9\\.\\-\\(\\)\\%]+", filename)) {int dotPos = filename.lastIndexOf('.');if (0 <= dotPos) {return filename.substring(dotPos + 1);}}}return "";}

其实他写的程序也是通过字符串的处理来做到的，不过他已经写好了我们直接用就是了。