文本中提取特定字符串的程序代码,Java代码库,德仔网

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【Java】文本中提取特定字符串的程序
作者:DDT / 发布于2013/1/15/ 827
import java.io.*;   
import java.util.*;   
   
class TextRep   
{   
    // the main function   
    public static void main (String[] args)   
    {   
        if(args.length!=2&&args.length!=3)   
        {   
            // invalid number of arguments specified at command line   
            System.out.println("Usage(s):\n");   
            System.out.println("  1.  java TextRep file_to_process \"search_for_word\" \"replace_with_word\"");    
            System.out.println("  2.  java TextRep file_to_process file_of_words_to_search_replace");      
            return;   
        }   
        try   
        {   
            // make 32k buffer for output   
            StringBuffer strOutput = new StringBuffer(32768);   
            // read input file into a byte array   
            byte[] pInput = ReadFile(args[0]);   
            // make a backup copy   
            WriteFile(args[0]+".backup.copy",pInput);   
            String strInput = new String(pInput);   
            if(args.length==3)   
            {   
                // check if words are empty   
                if(args[1].equals("")||args[2].equals(""))   
                {   
                    System.out.println("Cannot process empty words");   
                    return;   
                }   
                System.out.println("Replacing \""+args[1]+"\" with \""+args[2]+"\" in file: "+args[0]);   
                // find all instances of args[1] and replace it with args[2]   
                int nPos = 0;   
                while(true)   
                {   
                    int nIndex = strInput.indexOf(args[1],nPos);   
                    // if args[1] can no longer be found, then copy the rest of the input   
                    if(nIndex<0)   
                    {   
                        strOutput.append(strInput.substring(nPos));   
                        break;   
                    }   
                    // otherwise, replace it with args[2] and continue   
                    else   
                    {   
                        strOutput.append(strInput.substring(nPos,nIndex));   
                        strOutput.append(args[2]);   
                        nPos = nIndex+args[1].length();   
                    }   
                }   
                strInput = strOutput.toString();   
            }   
            else if(args.length==2)   
            {   
                System.out.println("Processing file: "+args[0]);   
                // create a string tokenizer with file args[1]   
                StringTokenizer tokens = new StringTokenizer(new String(ReadFile(args[1])),"\r\n");   
                // check to see of the tokenizer has even number of tokens   
                int nCount = tokens.countTokens();   
                if(nCount<1||nCount%2!=0)   
                {   
                    System.out.println("Invalid number of non-empty lines in file: "+args[1]);   
                    return;   
                }   
                // for each pair of string tokens, replace the first one with the next one   
                nCount = nCount/2;   
                for(int i=0;i<nCount;i++)   
                {   
                    // string to search in the input   
                    String strSearch = tokens.nextToken();   
                    // string used to replace the previous one   
                    String strReplace = tokens.nextToken();   
                    // check if words are empty   
                    if(strSearch.equals("")||strReplace.equals(""))   
                    {   
                        System.out.println("Cannot process empty words");   
                        return;   
                    }   
                    // replace each instance of strSearch with strReplace   
                    System.out.println("Replacing \""+strSearch+"\" with \""+strReplace+"\"");   
                    int nPos = 0;   
                    while(true)   
                    {   
                        int nIndex = strInput.indexOf(strSearch,nPos);   
                        // if strSearch can no longer be found, then copy the rest of the input   
                        if(nIndex<0)   
                        {   
                            strOutput.append(strInput.substring(nPos));   
                            break;   
                        }   
                        // otherwise, replace it with strReplace and continue   
                        else   
                        {   
                            strOutput.append(strInput.substring(nPos,nIndex));   
                            strOutput.append(strReplace);   
                            nPos = nIndex+strSearch.length();   
                        }   
                    }   
                    // continue to process the next pair of string tokens   
                    strInput = strOutput.toString();   
                    strOutput = new StringBuffer(32768);   
                }   
            }   
            // write the output string to file   
            WriteFile(args[0],strInput.getBytes());   
        }   
        catch(Exception e)   
        {   
            System.out.println(e.getMessage());   
        }   
    }   
   
    // helper function to read a file into a byte array   
    static public final byte[] ReadFile(String strFile) throws IOException   
    {   
        int nSize = 32768;   
        // open the input file stream   
        BufferedInputStream inStream = new BufferedInputStream(new FileInputStream(strFile),nSize);   
        byte[] pBuffer = new byte[nSize];   
        int nPos = 0;   
        // read bytes into a buffer   
        nPos += inStream.read(pBuffer,nPos,nSize-nPos);   
        // while the buffer is filled, double the buffer size and read more   
        while(nPos==nSize)   
        {   
            byte[] pTemp = pBuffer;   
            nSize *= 2;   
            pBuffer = new byte[nSize];   
            System.arraycopy(pTemp,0,pBuffer,0,nPos);   
            nPos += inStream.read(pBuffer,nPos,nSize-nPos);   
        }   
        // close the input stream   
        inStream.close();   
        if(nPos==0)   
        {   
            return "".getBytes();   
        }   
        // return data read into the buffer as a byte array   
        byte[] pData = new byte[nPos];   
        System.arraycopy(pBuffer,0,pData,0,nPos);   
        return pData;   
    }   
   
    // helper function to write a byte array into a file   
    static public final void WriteFile(String strFile, byte[] pData) throws IOException   
    {   
        BufferedOutputStream outStream = new BufferedOutputStream(new FileOutputStream(strFile),32768);        
        if(pData.length>0) outStream.write(pData,0,pData.length);   
        outStream.close();   
    }   
}
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