字符流

    String path = "D:\\dome.txt";   //文件路徑
    File file = new File(path);//生成文件對象
    FileWriter fw = new FileWriter(file,true);//true 寫進去的內容不覆蓋原先的內容，false 覆蓋
    String ss = "hgkdhgk";
    fw.write(ss);//把內容寫進去

    System.out.println("-----------");

    FileReader fr = new FileReader(file);
    char[] c = new char[1024];//字符數組容器
    while(fr.read(c)>0){//講讀取的內容放在字符容器中，並返回讀取的大小 
        System.out.print(c);
    }
    BufferedReader br = new  BufferedReader(fr);
     System.out.println(br.readLine());//讀取一行

     BufferedWriter bw = new BufferedWriter(fw);
     bw.write("jdfhdjhgjhgj");//把內容寫進去