자바 다양한 방식 으로 파일 읽 기,파일 내용 추가,파일 조작

 、         。

1、         
2、         
3、        
4、        

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.RandomAccessFile;
import java.io.Reader; 
public class ReadFromFile {
/**
   *           ，         ，   、  、     。
   * @param fileName     
   */
public static void readFileByBytes(String fileName){
   File file = new File(fileName);
   InputStream in = null;
   try {
    System.out.println("            ，       ：");
    //        
    in = new FileInputStream(file);
    int tempbyte;
    while((tempbyte=in.read()) != -1){
     System.out.write(tempbyte);
    }
    in.close();
   } catch (IOException e) {
    e.printStackTrace();
    return;
   }
   try {
    System.out.println("            ，       ：");
    //       
    byte[] tempbytes = new byte[100];
    int byteread = 0;
    in = new FileInputStream(fileName);
    ReadFromFile.showAvailableBytes(in);
    //            ，byteread         
    while ((byteread = in.read(tempbytes)) != -1){
     System.out.write(tempbytes, 0, byteread);
    }
   } catch (Exception e1) {
    e1.printStackTrace();
   } finally {
    if (in != null){
     try {
      in.close();
     } catch (IOException e1) {
     }
    }
   }
}
/**
   *           ，      ，        
   * @param fileName    
   */
public static void readFileByChars(String fileName){
   File file = new File(fileName);
   Reader reader = null;
   try {
    System.out.println("            ，       ：");
    //        
    reader = new InputStreamReader(new FileInputStream(file));
    int tempchar;
    while ((tempchar = reader.read()) != -1){
     //  windows ，\r
         ，      。
     //             ，     。
     //  ，   \r，    
。  ，        。
     if (((char)tempchar) != ''\r''){
      System.out.print((char)tempchar);
     }
    }
    reader.close();
   } catch (Exception e) {
    e.printStackTrace();
   }
   try {
    System.out.println("            ，       ：");
    //       
    char[] tempchars = new char[30];
    int charread = 0;
    reader = new InputStreamReader(new FileInputStream(fileName));
    //            ，charread        
    while ((charread = reader.read(tempchars))!=-1){
     //     \r   
     if ((charread == tempchars.length)&&(tempchars[tempchars.length-1] != ''\r'')){
      System.out.print(tempchars);
     }else{
      for (int i=0; i<charread; i++){
       if(tempchars[i] == ''\r''){
        continue;
       }else{
        System.out.print(tempchars[i]);
       }
      }
     }
    }
   
   } catch (Exception e1) {
    e1.printStackTrace();
   }finally {
    if (reader != null){
     try {
      reader.close();
     } catch (IOException e1) {
     }
    }
   }
}
/**
   *          ，             
   * @param fileName    
   */
public static void readFileByLines(String fileName){
   File file = new File(fileName);
   BufferedReader reader = null;
   try {
    System.out.println("           ，      ：");
    reader = new BufferedReader(new FileReader(file));
    String tempString = null;
    int line = 1;
    //      ，    null     
    while ((tempString = reader.readLine()) != null){
     //    
     System.out.println("line " + line + ": " + tempString);
     line++;
    }
    reader.close();
   } catch (IOException e) {
    e.printStackTrace();
   } finally {
    if (reader != null){
     try {
      reader.close();
     } catch (IOException e1) {
     }
    }
   }
}
/**
   *         
   * @param fileName    
   */
public static void readFileByRandomAccess(String fileName){
   RandomAccessFile randomFile = null;
   try {
    System.out.println("          ：");
    //            ，     
    randomFile = new RandomAccessFile(fileName, "r");
    //     ，   
    long fileLength = randomFile.length();
    //         
    int beginIndex = (fileLength > 4) ? 4 : 0;
    //           beginIndex  。
    randomFile.seek(beginIndex);
    byte[] bytes = new byte[10];
    int byteread = 0;
    //   10   ，        10   ，       。
    //           byteread
    while ((byteread = randomFile.read(bytes)) != -1){
     System.out.write(bytes, 0, byteread);
    }
   } catch (IOException e){
    e.printStackTrace();
   } finally {
    if (randomFile != null){
     try {
      randomFile.close();
     } catch (IOException e1) {
     }
    }
   }
}
/**
   *             
   * @param in
   */
private static void showAvailableBytes(InputStream in){
   try {
    System.out.println("             :" + in.available());
   } catch (IOException e) {
    e.printStackTrace();
   }
}

public static void main(String[] args) {
   String fileName = "C:/temp/newTemp.txt";
   ReadFromFile.readFileByBytes(fileName);
   ReadFromFile.readFileByChars(fileName);
   ReadFromFile.readFileByLines(fileName);
   ReadFromFile.readFileByRandomAccess(fileName);
}
}

 

 、          

import java.io.FileWriter;
import java.io.IOException;
import java.io.RandomAccessFile;

/**
*           
*/
public class AppendToFile {

/**
   * A      ：  RandomAccessFile
   * @param fileName    
   * @param content      
   */
public static void appendMethodA(String fileName, String content){
   try {
    //            ，     
    RandomAccessFile randomFile = new RandomAccessFile(fileName, "rw");
    //     ，   
    long fileLength = randomFile.length();
    //           。
    randomFile.seek(fileLength);
    randomFile.writeBytes(content);
    randomFile.close();
   } catch (IOException e){
    e.printStackTrace();
   }
}
/**
   * B      ：  FileWriter
   * @param fileName
   * @param content
   */
public static void appendMethodB(String fileName, String content){
   try {
    //        ，           true          
    FileWriter writer = new FileWriter(fileName, true);
    writer.write(content);
    writer.close();
   } catch (IOException e) {
    e.printStackTrace();
   }
}

public static void main(String[] args) {
   String fileName = "C:/temp/newTemp.txt";
   String content = "new append!";
   //   A    
   AppendToFile.appendMethodA(fileName, content);
   AppendToFile.appendMethodA(fileName, "append end. 
");
   //      
   ReadFromFile.readFileByLines(fileName);
   //   B    
   AppendToFile.appendMethodB(fileName, content);
   AppendToFile.appendMethodB(fileName, "append end. 
");
   //      
   ReadFromFile.readFileByLines(fileName);
}
} 
         

import java.io.*;

/**
* FileOperate.java
*        
* @author    http://blog.sina.com.cn/m/yangcai
*      1.0
*/

public class FileOperate
{

   public FileOperate()
   {
   }
   /**
      *     
      */
   public void newFolder(String folderPath)
   {
       try
       {
           String filePath = folderPath;
           filePath = filePath.toString();
           File myFilePath = new File(filePath);
           if(!myFilePath.exists())
           {
               myFilePath.mkdir();
           }
           System.out.println("           ");
       }
       catch(Exception e)
       {
           System.out.println("        ");
           e.printStackTrace();
       }
   }
   /**
      *     
      */
   public void newFile(String filePathAndName, String fileContent)
   {
       try
       {
           String filePath = filePathAndName;
           filePath = filePath.toString();
           File myFilePath = new File(filePath);
           if (!myFilePath.exists())
           {
               myFilePath.createNewFile();
           }
           FileWriter resultFile = new FileWriter(myFilePath);
           PrintWriter myFile = new PrintWriter(resultFile);
           String strContent = fileContent;
           myFile.println(strContent);
           resultFile.close();
           System.out.println("           ");
       }
       catch (Exception e)
       {
           System.out.println("        ");
           e.printStackTrace();
       }
   }
   /**
      *     
      */
   public void delFile(String filePathAndName)
   {
       try
       {
           String filePath = filePathAndName;
           filePath = filePath.toString();
           File myDelFile = new File(filePath);
           myDelFile.delete();
           System.out.println("           ");
       }
       catch (Exception e)
       {
           System.out.println("        ");
           e.printStackTrace();
       }
   }
   /**
      *      
      */
   public void delFolder(String folderPath)
   {
       try
       {
           delAllFile(folderPath); //         
           String filePath = folderPath;
           filePath = filePath.toString();
           File myFilePath = new File(filePath);
           if(myFilePath.delete()) { //      
           System.out.println("     " + folderPath + "       ");
} else {
               System.out.println("     " + folderPath + "       ");
}
       }
       catch (Exception e)
       {
           System.out.println("         ");
           e.printStackTrace();
       }
   }
   /**
      *             
      * @param path String         c:/fqf
      */
   public void delAllFile(String path)
   {
       File file = new File(path);
       if(!file.exists())
       {
           return;
       }
       if(!file.isDirectory())
       {
           return;
       }
       String[] tempList = file.list();
       File temp = null;
       for (int i = 0; i < tempList.length; i++)
       {
           if(path.endsWith(File.separator))
           {
               temp = new File(path + tempList[i]);
           }
           else
           {
               temp = new File(path + File.separator + tempList[i]);
           }
           if (temp.isFile())
           {
               temp.delete();
           }
           if (temp.isDirectory())
           {
               //delAllFile(path+"/"+ tempList[i]);//           
               delFolder(path+ File.separatorChar + tempList[i]);//       
           }
       }
       System.out.println("           ");
   }
   /**
      *       
      * @param oldPath String        ：c:/fqf.txt
      * @param newPath String        ：f:/fqf.txt
      */
   public void copyFile(String oldPath, String newPath)
   {
       try
       {
           int bytesum = 0;
           int byteread = 0;
           File oldfile = new File(oldPath);
           if (oldfile.exists())
           {
               //     
               InputStream inStream = new FileInputStream(oldPath); //     
               FileOutputStream fs = new FileOutputStream(newPath);
               byte[] buffer = new byte[1444];
               while ( (byteread = inStream.read(buffer)) != -1)
               {
                   bytesum += byteread; //        
                   System.out.println(bytesum);
                   fs.write(buffer, 0, byteread);
               }
               inStream.close();
           }
           System.out.println("            ");
       }
       catch (Exception e)
       {
           System.out.println("          ");
           e.printStackTrace();
       }
   }
   /**
      *          
      * @param oldPath String        ：c:/fqf
      * @param newPath String        ：f:/fqf/ff
      */
   public void copyFolder(String oldPath, String newPath)
   {
       try
       {
           (new File(newPath)).mkdirs(); //                
           File a=new File(oldPath);
           String[] file=a.list();
           File temp=null;
           for (int i = 0; i < file.length; i++)
           {
               if(oldPath.endsWith(File.separator))
               {
                   temp=new File(oldPath+file[i]);
               }
               else
               {
                   temp=new File(oldPath+File.separator+file[i]);
               }
               if(temp.isFile())
               {
                   FileInputStream input = new FileInputStream(temp);
                   FileOutputStream output = new FileOutputStream(newPath + "/" +
                   (temp.getName()).toString());
                   byte[] b = new byte[1024 * 5];
                   int len;
                   while ( (len = input.read(b)) != -1)
                   {
                       output.write(b, 0, len);
                   }
                   output.flush();
                   output.close();
                   input.close();
               }
               if(temp.isDirectory())
               {
                   //       
                   copyFolder(oldPath+"/"+file[i],newPath+"/"+file[i]);
               }
           }
           System.out.println("            ");
       }
       catch (Exception e)
       {
           System.out.println("             ");
           e.printStackTrace();
       }
   }
   /**
      *          
      * @param oldPath String  ：c:/fqf.txt
      * @param newPath String  ：d:/fqf.txt
      */
   public void moveFile(String oldPath, String newPath)
   {
       copyFile(oldPath, newPath);
       delFile(oldPath);
   }
   /**
      *          
      * @param oldPath String  ：c:/fqf.txt
      * @param newPath String  ：d:/fqf.txt
      */
   public void moveFolder(String oldPath, String newPath)
   {
       copyFolder(oldPath, newPath);
       delFolder(oldPath);
   }
   public static void main(String args[])
   {
       String aa,bb;
       boolean exitnow=false;
       System.out.println("       [1]     ：    ");
       System.out.println("       [2]     ：    ");
       System.out.println("       [3]     ：    ");
       System.out.println("       [4]     ：     ");
       System.out.println("       [5]     ：            ");
       System.out.println("       [6]     ：    ");
       System.out.println("       [7]     ：          ");
       System.out.println("       [8]     ：         ");
       System.out.println("       [9]     ：          ");
       System.out.println("       [10]     ");
       while(!exitnow)
       {
           FileOperate fo=new FileOperate();
           try
           {
               BufferedReader Bin=new BufferedReader(new InputStreamReader(System.in));
               String a=Bin.readLine();
               int b=Integer.parseInt(a);
               switch(b)
               {
                   case 1:System.out.println("               ");
                   aa=Bin.readLine();
                   fo.newFolder(aa);
                   break;
                   case 2:System.out.println("               ");
                   aa=Bin.readLine();
                   System.out.println("    "+aa+"    ");
                   bb=Bin.readLine();
                   fo.newFile(aa,bb);
                   break;
                   case 3:System.out.println("               ");
                   aa=Bin.readLine();
                   fo.delFile(aa);
                   break;
                   case 4:System.out.println("               ");
                   aa=Bin.readLine();
                   fo.delFolder(aa);
                   break;
                   case 5:System.out.println("               ");
                   aa=Bin.readLine();
                   fo.delAllFile(aa);
                   break;
                   case 6:System.out.println("               ");
                   aa=Bin.readLine();
                   System.out.println("        ");
                   bb=Bin.readLine();
                   fo.copyFile(aa,bb);
                   break;
                   case 7:System.out.println("                ");
                   aa=Bin.readLine();
                   System.out.println("        ");
                   bb=Bin.readLine();
                   fo.copyFolder(aa,bb);
                   break;
                   case 8:System.out.println("                ");
                   aa=Bin.readLine();
                   System.out.println("        ");
                   bb=Bin.readLine();
                   fo.moveFile(aa,bb);
                   break;
                   case 9:System.out.println("                ");
                   aa=Bin.readLine();
                   System.out.println("        ");
                   bb=Bin.readLine();
                   fo.moveFolder(aa,bb);
                   break;
                   case 10:exitnow=true;
                   System.out.println("    ，   ");
                   break;
                   default:System.out.println("    .   1-10    ");
               }
               System.out.println("       ");
           }
           catch(Exception e)
           {
               System.out.println("           ");
           }
       }
   }
}


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