//将文件中的"new PushBackTest"字符串之前的内容输出出来 使用PushBackInputStream和PushBackOutputStream流

import java.io.*;

public class PushBackTest

{

public static void main(String[] args)

{

try(PushbackReader pr = new PushbackReader(new FileReader("PushBackTest.java"),64))

{

char[] a = new char[32];

int hasRead = 0;

int index = 0;

String lastcontent = "";

while ((hasRead = pr.read(a))>0)

{

String content = new String(a , 0 , hasRead);

//System.out.print(new String(a , 0 , hasRead));

if ((index = (lastcontent + content).indexOf("new PushbackReader")) > 0)

{

if (index > 32)

{

a = new char[index];

}

pr.unread((lastcontent + content).toCharArray());

pr.read(a , 0 , index);

lastcontent = new String(a , 0 , index);

System.out.print(lastcontent);

System.out.println("接下来就是关键词后面的文件内容");

break;

}

else

{

System.out.print(lastcontent);

lastcontent = content;

}

}

}

catch (IOException ex)

{

ex.printStackTrace();

}

}

}