Why people use BufferedReader to read post data

Why people use BufferedReader to read post data

People sometimes use BufferedReader to read post data.
BufferedReader bReader;
String postData = null;
try {
bReader = request.getReader();
char[] buf = new char[1024];
int len;
StringBuilder sBuilder = new StringBuilder();
while ((len = bReader.read(buf)) != -1) {
sBuilder.append(buf, 0, len);
}
postData = sBuilder.toString();
} catch (IOException e) {
bReader = null;
}
When should I use this to get parameter, how about request.getParameter()?