IO:字节流转化字符流

InputStreamReader类可以将InputStream字节流转化成Reader字符流：

void inputStreamReader() {
        // InputStreamReader类可以将InputStream字节流转化成Reader字符流
        // 中文无乱码
        File file = new File("e:\test.txt");
        InputStream inputStream = null;
        InputStreamReader isr = null;
        char[] ch = new char[24];
        int len;
        StringBuilder sb = new StringBuilder();
        try {
            inputStream = new FileInputStream(file);
            isr = new InputStreamReader(inputStream);
            while ((len = isr.read(ch)) != -1) {
                sb.append(ch);
            }
            System.out.println(sb);
            // 获取文件编码格式
            System.out.println(isr.getEncoding());
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } finally {
            if (isr != null) {
                try {
                    isr.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }
    }