字节流和字符流的read方法

public class Test {    public void fileOutput() throws Exception {        File file = new File("D:/2.txt");        FileOutputStream fileOutputStream = new FileOutputStream(file);        String s = "abcdefg";        fileOutputStream.write(s.getBytes());        fileOutputStream.close();    }    /**     * fileInputStream.read()是一个字节一个字节的读，返回值为根据ascii码表转成的int值     * 输出结果     97     a     98     b     99     c     100     d     101     e     102     f     103     g     *     * @throws Exception     */    public void fileInput() throws Exception {        File file = new File("D:/2.txt");        FileInputStream fileInputStream = new FileInputStream(file);        int a;        while ((a = fileInputStream.read()) != -1) {            System.out.println(a);            System.out.println((char)a);        }        fileInputStream.close();    }    /**     * 输出结果：     * 97     * 98     * 99     * 100     * 101     * 102     * 103     * [B@5a8e6209     * abcdefg     *     * @throws Exception     */    public void fileInput2() throws Exception {        File file = new File("D:/2.txt");        FileInputStream fileInputStream = new FileInputStream(file);        int a;        int[] b = new int[10];        byte[] c = new byte[10];        int len = 0;        while ((a = fileInputStream.read()) != -1) {            b[len] = a;            c[len] = (byte) a;            len++;        }        for (int i = 0; i < len; i++) {            System.out.println(b[i]);        }        System.out.println(c.toString());        System.out.println(new String(c));        fileInputStream.close();    }    /**     * 带参数read(byte[] b)方法，读取参数b字节大小     * 其返回值为int类型，the total number of bytes read into the buffer, or -1 if there is no more data because the end of the file has been reached.     * 输出结果：     * 7     * -1     * abcdefg     *     * @throws Exception     */    public void fileInput3() throws Exception {        File file = new File("D:/2.txt");        FileInputStream fileInputStream = new FileInputStream(file);        byte[] b = new byte[10];        byte[] bb = new byte[5];        int a = fileInputStream.read(b);        int c = fileInputStream.read(bb);        System.out.println(a);        System.out.println(c);        System.out.println(new String(b));        fileInputStream.close();    }    /**     * 输出结果     * 7     * abcdefg     *     * @throws Exception     */    public void fileInput4() throws Exception {        File file = new File("D:/2.txt");        FileInputStream fileInputStream = new FileInputStream(file);        byte[] b = new byte[10];        int a = fileInputStream.read(b, 0, new Long(file.length()).intValue());        System.out.println(a);        System.out.println(new String(b));        fileInputStream.close();    }    /**     * 输出结果：     * 97     * 98     * 99     * 100     * 101     * 102     * 103     * @throws Exception     */    public void fileReader() throws Exception {        File file = new File("D:/2.txt");        FileReader fileReader = new FileReader(file);        int a;        while ((a=fileReader.read())!=-1){            System.out.println(a);        }        fileReader.close();    }    /**     * 输出结果：     * abcdefg     * @throws Exception     */    public void fileReader2() throws Exception {        File file = new File("D:/2.txt");        FileReader fileReader = new FileReader(file);        int a;        int len=0;        byte[] b=new byte[10];        while ((a=fileReader.read())!=-1){            b[len]=(byte) a;            len++;        }        System.out.println(new String(b));        fileReader.close();    }    /**     * 输出结果：     * abcdefg     * @throws Exception     */    public void fileReader3() throws Exception {        File file = new File("D:/2.txt");        FileReader fileReader = new FileReader(file);        char[] cbuf=new char[10];        fileReader.read(cbuf);        System.out.println(new String(cbuf));        fileReader.close();    }    public static void main(String[] args) throws Exception {        Test test = new Test();        test.fileInput(); 　　　　　　　　    }}