URL处理细节

String fileName = imgUrl.substring(imgUrl.lastIndexOf('/') + 1, imgUrl.length());

try {
// 文件名里面可能有中文或者空格，所以这里要进行处理。但空格又会被URLEncoder转义为加号
String urlTail = URLEncoder.encode(fileName, "UTF-8");
// 因此要将加号转化为UTF-8格式的%20
imgUrl = imgUrl.substring(0, imgUrl.lastIndexOf('/') + 1) + urlTail.replaceAll("\\+", "\\%20");

} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}