IO stream reads data and some Chinese characters are garbled

        response.setContentType("text/html;charset=UTF-8");
		request.setCharacterEncoding("UTF-8");
//		response.setCharacterEncoding("UTF-8");
		OutputStream os = null;
		InputStream is = null;
		try {
			StringBuilder sb = new StringBuilder("");
			is = request.getInputStream();
			byte[] buffer = new byte[1024];
			while (is.read(buffer) != -1) {
				sb.append(new String(buffer));
			}
			String xml = sb.toString().trim();
                } catch (Exception e) {
			e.printStackTrace ();
		}

 The above code reads a large amount of data, and the data contains Chinese characters, so there will be some garbled Chinese characters.

 

Analyze the reasons:

1. UTF-8 is a variable-length character encoding for Unicode, also known as Universal Code. It can be used on web pages to display Chinese, Simplified, Traditional and other languages ​​(such as English, Japanese, Korean) on a unified page.

2. Common Chinese characters use utf-8 encoding to occupy 3 bytes (about 20,000 words), but most Chinese characters in the super large character set occupy 4 bytes (in the unicode encoding system, U+20000 starts with 50,000 characters) multiple Chinese characters). English characters and numbers occupy 1 byte.

3. The buffer in the program is 1024. In this case, some Chinese characters will only be read in part, and part of the Chinese characters will be garbled when re-encoded.

solution:

                response.setContentType("text/html;charset=UTF-8");
                request.setCharacterEncoding("UTF-8");
//              response.setCharacterEncoding("UTF-8");
                OutputStream os = null;
                InputStream is = null;
                InputStreamReader isr = null;
                BufferedReader br = null;
                try {
                        StringBuilder sb = new StringBuilder("");
                        is = request.getInputStream();
                        isr = new InputStreamReader(is,"UTF-8");
                        br = new BufferedReader(isr);
                        String line = null;
                        while ((line = br.readLine()) != null) {
                             sb.append(line );
                        }
                        String xml = sb.toString().trim();
                } catch (Exception e) {
                    e.printStackTrace ();
                }