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。