public static void main(String[] args) throws IOException {

        FileWriter fWriter = new FileWriter("c:\\1.txt");

        fWriter.write(100);

        char[] c = {'a','b','c','d'};

        fWriter.write(c);

        //截取下标为1、2的元素

        fWriter.write(c, 1, 2);

        fWriter.write("你好世界");

        fWriter.flush();//刷新

        fWriter.close();

    }    

//flush  和close区别

//flush用来刷新缓冲区的  只有字符流才需要刷新

    public static void main(String[] args) throws Exception {

        FileReader fileReader  = new FileReader("c:\\1.txt");

//一个个字符读取

//        int len=0;

//        while((len=fileReader.read())!=-1){

//            System.out.print((char)len);

//        }

        char[] ch =new char[1024];// 一次读1024个字符

        int len= 0;

        while((len=fileReader.read(ch))!=-1){

            System.out.println(new String(ch,0,len));

        }

        fileReader.close();

    }