Java-流的简单使用：读取文件、写入文件（面试题：删除注释代码）

摘要：前天面试Android时遇到机试，题目是删除注释中的代码。机试开始时不能上网，我恰好忘了读写字符流的相关代码API，幸好后来能上网查关于流的API，最终得以把程序写出来。

 

题目：请编程将Example.c文件中的所有注释删除，将结果写入Example.i文件中。

输入用例Example.c：

struct a {

    char a /*2392839238923 /*kasdlfjasld*/;

    char b; //23232392839

};

/*

askdashfla'

asdfalskdfhlksafdhla

fasdjfhalsdjfhlasdf

askjdfhlkajds

* /

 */

void Function(int param /*232323* / */)

{ 

    //*2323234234l

    int i = 1;//2923939

    char str[] = "/*232323";

    int j = 0;

    i = i / j * i;

    strcpy(str, "/*lakjslkdflksd*/");

}

 

我编写的程序：

import java.io.BufferedReader;

import java.io.BufferedWriter;

import java.io.File;

import java.io.FileNotFoundException;

import java.io.FileReader;

import java.io.FileWriter;

import java.io.IOException;



public class Test {

    public static void main(String args[])

    {

        String InputPath="../Example_1.c";

        String OutputPath="../Example_1.i";

        

        String Data=LoadFile(InputPath);

        Data=Handle(Data);



        WriteFile(Data,OutputPath);

    }

    

    //把文件中的数据转化为字符串



    private static String LoadFile(String path)

    {

        File file = new File(path);

        BufferedReader reader=null;

        String temp;

        String result="";

        

        

        try {

            reader =new BufferedReader(new FileReader(file));

            

            while((temp=reader.readLine())!=null)

            {

                result=result+temp+"\r\n";

            }

        } catch (FileNotFoundException e) {

                // TODO Auto-generated catch block

            e.printStackTrace();

        } catch (IOException e) {

            // TODO Auto-generated catch block

            e.printStackTrace();

        }

        System.out.println(result);    

        return result;

    }

    

    //把数据写进文件

    private static void WriteFile(String data,String path)

    {

        try {

            FileWriter fw=new FileWriter(path);

            BufferedWriter bw=new BufferedWriter(fw);



            bw.write(data);

            

            bw.close();

            fw.close();

            

            

        } catch (IOException e) {

            // TODO Auto-generated catch block

            e.printStackTrace();

        }

        return;

    }

    

    //删掉注释的方法

    private static String Handle(String data)

    {

        StringBuffer sb= new StringBuffer();

        int posStar = 0,posEnd=0,i=0;

        while(i<data.length())

        {

            System.out.print(data.charAt(i));

            if(data.charAt(i)=='"')

            {

                do

                {

                    sb.append(data.charAt(i));

                    i++;

                }while(data.charAt(i)!='"');

                sb.append(data.charAt(i));

                i++;

                continue;

            }

            else if(data.charAt(i)=='/')

            {

                if(data.charAt(i+1)=='/')

                {

                    do

                    {

                        i++;

                    }while(data.charAt(i)!='\r');

                    sb.append(data.charAt(i));

                    i++;

                    continue;

                }

              

                else if(data.charAt(i+1)=='*')

                {

                    

                    do

                    {

                        i++;

                    }while(data.charAt(i)!='*'||((data.charAt(i)=='*')&&(data.charAt(i-1)=='/')));

                    do

                    {

                        i++;

                    }while(data.charAt(i)!='/');

                    

                    i++;

                    posStar=i;

                    continue;

                }

            }

            else if(data.charAt(i)=='*')                

            {

                if(data.charAt(i+1)=='/')

                {

                    

                    posEnd=i;

                    i=i+2;

                    System.out.println(posStar+" "+posEnd+" "+sb.length());

                    sb.delete(sb.length()-(posEnd-posStar), sb.length());

                    continue;

                }

                else

                {

                    while(data.charAt(i+1)==' ')

                    {

                        sb.append(data.charAt(i));

                        i++;

                        

                    }

                    if(data.charAt(i+1)=='/')

                    {

                        posEnd=i;

                        i=i+2;

                        sb.delete(sb.length()-(posEnd-posStar), sb.length());

                        continue;

                    }

                    else{

                        continue;

                    }

                }

            }

            sb.append(data.charAt(i));

            i++;

        }

        return new String(sb);

    }

    

}

 

输出结果：

struct a {

    char a ;

    char b; 

};



void Function(int param )

{ 

    

    int i = 1;

    char str[] = "/*232323";

    int j = 0;

    i = i / j * i;

    strcpy(str, "/*lakjslkdflksd*/");

}

 

还有更好的答案吗？望共同探讨。