20220518_字符流的读取，用字符数组char[]

public class FileReaderDemo2 {
    public static void main(String[] args) throws Exception {
        Reader in = new FileReader("CertExam\\src\\dataTest.txt");

        char[] chs = new char[7]; //7 chars
        int num;
        /**
         * in.read(char[])返回的是每次读到的单字符数量num，这是一个int变量
         * 但桶，char[]里已经装了好些个单字符
         * 遍历char[]并且(int)这些字符，得到字节码
         * 用数组的值输出方式Arrays.toString(字符数组char[]),就看到这些字符
         */
        while ((num = in.read(chs)) != -1) {
            if (num == chs.length) {
                for (char ch : chs) {
                    System.out.print((int) ch + " ");
                }
                System.out.println("\n" + Arrays.toString(chs));
            } else {
                char[] subChs = Arrays.copyOf(chs,num);
                for (char subCh : subChs) {
                    System.out.print((int)subCh+" ");
                }
                System.out.println("\n" + Arrays.toString(subChs));
            }
        }
    }
}

源TXT文件内容如下
!@#$%^&*()-=[];'./,ABCD1234abcd