java读取文件

            InputStream inputStream = new FileInputStream(file);
            int temp = -1;
            StringBuilder sb = new StringBuilder();
            while((temp = inputStream.read()) != -1){
                sb.append((char)temp);
            }
            inputStream.close();

            InputStream inputStream = new FileInputStream(file);
            byte[] bytes = new byte[10];
            StringBuilder sb = new StringBuilder();
            int length = -1;
            while((length = inputStream.read(bytes))!= -1){
                sb.append(new String(bytes,0,length,Charset.forName("utf-8")));
            }
            inputStream.close();

            InputStream inputStream = new FileInputStream(file);
            InputStreamReader isr = new InputStreamReader(inputStream,Charset.forName("utf-8"));
            StringBuilder sb = new StringBuilder();
            int temp = -1;
            while((temp = (isr.read()))!= -1){
                sb.append((char)temp);
            }
            inputStream.close();
            isr.close();

InputStream inputStream = new FileInputStream(file);
            InputStreamReader isr = new InputStreamReader(inputStream,Charset.forName("utf-8"));
            BufferedReader bufferedReader = new BufferedReader(isr);
            StringBuilder sb = new StringBuilder();
            String line = null;
            while((line = bufferedReader.readLine())!=null){
                sb.append(line + ‘\n‘);
            }
            inputStream.close();
            isr.close();
            bufferedReader.close();