learning java 推回输入流

import java.io.FileNotFoundException;

import java.io.FileReader;

import java.io.IOException;

import java.io.PushbackReader;

public class PushbackTest {

    public static void main(String[] args) {

        try {

            var pr = new PushbackReader(new FileReader("src/com/company/PushbackTest.java"),);

            {

                var buf = new char[];

                var lastContent = "";

                var hasRead = ;

                while ((hasRead = pr.read(buf)) > ){

                    var content = new String(buf, ,hasRead);

                    var targetIndex = ;

                    if ((targetIndex = (lastContent + content).indexOf("new PushbackReader")) > ){

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

                        if (targetIndex >  ){

                            buf = new char[targetIndex];

                        }

                        pr.read(buf,   , targetIndex);

                        System.out.println(new String(buf,, targetIndex));

                        System.exit();

                    }

                    else {

                        System.out.println(lastContent);

                        lastContent = content;

                    }

                }

            }

        } catch (FileNotFoundException e) {

            e.printStackTrace();

        } catch (IOException e) {

            e.printStackTrace();

        }

    }

}

output:

package com.company;

import j

ava.io.FileNotFoundException;

i

mport java.io.FileReader;

impor

t java.io.IOException;

import j

ava.io.PushbackReader;

public

 class PushbackTest {

    publi

c static void main(String[] args

) {

        try {

            var pr =