java 回退流

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.PushbackInputStream;


public class PushInputStreamDemo {
    public static void main(String[] args) throws Exception {
        String str="www.hjw.com";
        ByteArrayInputStream bai=new ByteArrayInputStream(str.getBytes());
        PushbackInputStream push=new PushbackInputStream(bai);
        System.out.println("读取后的数据为：");
        int temp=0;
        while((temp=push.read())!=-1){
            if(temp=='.'){
                push.unread(temp);
                temp=push.read();
                System.out.print("（退回"+(char)temp+")");//为了显示内容，打印出来
            }else{
                System.out.print((char)temp);
            }
        }
    }
}