InputStreamReader（字符输入转换流 ）

• 解决不同编码时，字符流读取文本内容乱码的问题

public static void main(String[] args) {
        try (
                //1.得到文件的原始字节流(GBK的字节流形式)
                FileInputStream is = new FileInputStream("src/666.txt");
                //2.把原始的字节流输入按照指定的字符集编码转换成字符输入流
                InputStreamReader isr = new InputStreamReader(is, "GBK");
                //3.再转换成缓冲流
                BufferedReader br = new BufferedReader(isr)
        ) {
            String line;
            while((line = br.readLine()) != null){
                System.out.println(line);
            }

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

OutputStreamWriter（字符输出转换流 ）

public static void main(String[] args) {
        try (
                FileOutputStream os = new FileOutputStream("src/666.txt");
                OutputStreamWriter osw = new OutputStreamWriter(os,"GBK");
                BufferedWriter bw = new BufferedWriter(osw)
        ) {

            bw.write("我是你爹");
            bw.newLine();
            bw.write("我是你爹");

        } catch (Exception e) {
            e.printStackTrace();
        }
    }