JAVA IO 的几个基本概念 ,need help

zhshqzyc

What is meant by?

1. 
   
2. new BufferedInputStream(
   
3. new FileInputStream("filename")));
   

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and

1. 
   
2. new DataInputStream(
   
3. new BufferedInputStream(
   
4. new FileInputStream("filename")));
   

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then

1. 
   
2. new BufferedReader(
   
3. new DataInputStream(
   
4. new BufferedInputStream(
   
5. new FileInputStream("filename"))));
   

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aixy

为打开一个文件以便输入，需要使用一个FileInputStream，同时将一个String或File对象作为文件名使用。为提高速度，最好先对文件进行缓冲处理，从而获得用于一个BufferedInputStream的构建器的结果句柄。为了以格式化的形式读取输入数据，我们将那个结果句柄赋给用于一个DataInputStream的构建器。如果要使用readLine()，那时需要使用一个BufferedReader。
DataInputStream中的readLine()方法是被Deprecated的，可以参看jdk文档中的描述：

readLine()
          Deprecated. This method does not properly convert bytes to characters. As of JDK 1.1, the preferred way to read lines of text is via the BufferedReader.readLine() method. Programs that use the DataInputStream class to read lines can be converted to use the BufferedReader class by replacing code of the form:
     DataInputStream d = new DataInputStream(in);
with:
     BufferedReader d
          = new BufferedReader(new InputStreamReader(in));