转换流 ------ OutputStreamWriter 类与 InputStreamReader 类

OutputStreamWriter：是 Writer 的子类，将输出的字节变为字符流，即将一个字符流的输出对象变为字节流的输出对象
InputStreamReader：是 Reader 的子类，将输入的字节变为字符流，即将一个字节流的输入对象变为字符流的输入对象

1 、将字节输出流变为字符输出流

public class OutputStreamWriterDemo01 {
    public static void main(String[] args) {
        File file = new File("e:" + File.separator + "test.txt");
        try {
            Writer out = new OutputStreamWriter(new FileOutputStream(file));
            out.write("hello world");
            out.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

2 、将字节输入流变为字符输入流

public class InputStreamReaderDemo {
    public static void main(String[] args) {
        File file = new File("e:" + File.separator + "test.txt");
        try {
            Reader input = new InputStreamReader(new FileInputStream(file));
            char[] c = new char[(int) file.length()];
            input.read(c);
            input.close();
            System.out.println("内容为：" + new String(c));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}