Java文件操作大全（转载的）

 //1.创建文件夹 
    //import java.io.*; 
    File myFolderPath = new File(str1); 
    try { 
        if (!myFolderPath.exists()) { 
           myFolderPath.mkdir(); 
        } 
    } 
    catch (Exception e) { 
        System.out.println("新建目录操作出错"); 
        e.printStackTrace(); 
    }  

    //2.创建文件 
    //import java.io.*; 
    File myFilePath = new File(str1); 
    try { 
        if (!myFilePath.exists()) { 
            myFilePath.createNewFile(); 
        } 
        FileWriter resultFile = new FileWriter(myFilePath); 
        PrintWriter myFile = new PrintWriter(resultFile); 
        myFile.println(str2); 
        resultFile.close(); 
    } 
    catch (Exception e) { 
        System.out.println("新建文件操作出错"); 
        e.printStackTrace(); 
    }  

    //3.删除文件 
    //import java.io.*; 
    File myDelFile = new File(str1); 
    try { 
        myDelFile.delete(); 
    } 
    catch (Exception e) { 
        System.out.println("删除文件操作出错"); 
        e.printStackTrace(); 
    }  

    //4.删除文件夹 
    //import java.io.*; 
    File delFolderPath = new File(str1); 
    try { 
        delFolderPath.delete(); //删除空文件夹 
    } 
    catch (Exception e) { 
        System.out.println("删除文件夹操作出错"); 
        e.printStackTrace(); 
    }  

    //5.删除一个文件下夹所有的文件夹 
    //import java.io.*; 
    File delfile=new File(str1); 
    File[] files=delfile.listFiles(); 
    for(int i=0;i<files.length;i++){ 
        if(files[i].isDirectory()){ 
            files[i].delete(); 
        } 
    }   
     
    //6.清空文件夹 
    //import java.io.*; 
    File delfilefolder=new File(str1); 
    try { 
        if (!delfilefolder.exists()) { 
            delfilefolder.delete(); 
        } 
        delfilefolder.mkdir(); 
    } 
    catch (Exception e) { 
        System.out.println("清空目录操作出错"); 
        e.printStackTrace(); 
    }  

    //7.读取文件 
    //import java.io.*; 
    // 逐行读取数据 
    FileReader fr = new FileReader(str1); 
    BufferedReader br = new BufferedReader(fr); 
    String str2 = br.readLine(); 
    while (str2 != null) { 
        str3 
        str2 = br.readLine(); 
    } 
    br.close(); 
    fr.close();  

    //8.写入文件 
    //import java.io.*; 
    // 将数据写入文件 
    try { 
        FileWriter fw = new FileWriter(str1); 
        fw.write(str2); 
        fw.flush(); 
        fw.close();  
    } catch (IOException e) { 
        e.printStackTrace(); 
    } 

    //9.写入随机文件 
    //import java.io.*; 
    try { 
        RandomAcessFile logFile=new RandomAcessFile(str1,"rw"); 
        long lg=logFile.length(); 
        logFile.seek(str2); 
        logFile.writeByte(str3); 
    }catch(IOException ioe){ 
        System.out.println("无法写入文件："+ioe.getMessage()); 
    }  

    //10.读取文件属性 
    //import java.io.*; 
    // 文件属性的取得 
    File f = new File(str1); 
    if (af.exists()) { 
        System.out.println(f.getName() + "的属性如下： 文件长度为：" + f.length()); 
        System.out.println(f.isFile() ? "是文件" : "不是文件"); 
        System.out.println(f.isDirectory() ? "是目录" : "不是目录"); 
        System.out.println(f.canRead() ? "可读取" : "不"); 
        System.out.println(f.canWrite() ? "是隐藏文件" : ""); 
        System.out.println("文件夹的最后修改日期为：" + new Date(f.lastModified())); 
        } else { 
        System.out.println(f.getName() + "的属性如下："); 
        System.out.println(f.isFile() ? "是文件" : "不是文件"); 
        System.out.println(f.isDirectory() ? "是目录" : "不是目录"); 
        System.out.println(f.canRead() ? "可读取" : "不"); 
        System.out.println(f.canWrite() ? "是隐藏文件" : ""); 
        System.out.println("文件的最后修改日期为：" + new Date(f.lastModified())); 
    } 
    if(f.canRead()){ 
        str2 
    } 
    if(f.canWrite()){ 
        str3 
    } 

    //11.写入属性 
    //import java.io.*; 
    File filereadonly=new File(str1); 
    try { 
        boolean b=filereadonly.setReadOnly(); 
    } 
    catch (Exception e) { 
        System.out.println("拒绝写访问："+e.printStackTrace()); 
    }  

    //12.枚举一个文件夹中的所有文件 
    //import java.io.*; 
    //import java.util.*; 
    LinkedList<String> folderList = new LinkedList<String>(); 
    folderList.add(str1); 
    while (folderList.size() > 0) { 
        File file = new File(folderList.peek()); 
        folderList.removeLast(); 
        File[] files = file.listFiles(); 
        ArrayList<File> fileList = new ArrayList<File>(); 
        for (int i = 0; i < files.length; i++) { 
            if (files[i].isDirectory()) { 
                folderList.add(files[i].getPath()); 
            } else { 
                fileList.add(files[i]); 
            } 
        } 
        for (File f : fileList) { 
            str2=f.getAbsoluteFile(); 
            str3 
        } 
    } 

    //13.复制文件夹  
    //import java.io.*; 
    //import java.util.*; 
    LinkedList<String> folderList = new LinkedList<String>(); 
    folderList.add(str1); 
    LinkedList<String> folderList2 = new LinkedList<String>(); 
    folderList2.add(str2+ str1.substring(str1.lastIndexOf("\"))); 
    while (folderList.size() > 0) { 
        (new File(folderList2.peek())).mkdirs(); // 如果文件夹不存在 则建立新文件夹 
        File folders = new File(folderList.peek()); 
        String[] file = folders.list(); 
        File temp = null; 
        try { 
            for (int i = 0; i < file.length; i++) { 
                if (folderList.peek().endsWith(File.separator)) { 
                    temp = new File(folderList.peek() + File.separator 
                    + file[i]); 
                } else { 
                    temp = new File(folderList.peek() + File.separator + file[i]); 
                } 
                if (temp.isFile()) { 
                    FileInputStream input = new FileInputStream(temp); 
                    FileOutputStream output = new FileOutputStream( 
                    folderList2.peek() + File.separator + (temp.getName()).toString()); 
                    byte[] b = new byte[5120]; 
                    int len; 
                    while ((len = input.read(b)) != -1) { 
                        output.write(b, 0, len); 
                    } 
                    output.flush(); 
                    output.close(); 
                    input.close(); 
                } 
                if (temp.isDirectory()) {// 如果是子文件夹 
                    for (File f : temp.listFiles()) { 
                        if (f.isDirectory()) { 
                            folderList.add(f.getPath()); 
                            folderList2.add(folderList2.peek() 
                            + File.separator + f.getName()); 
                        } 
                    } 
                } 
            } 
        } catch (Exception e) { 
        //System.out.println("复制整个文件夹内容操作出错"); 
            e.printStackTrace(); 
        } 
        folderList.removeFirst(); 
        folderList2.removeFirst(); 
    } 

    //14.复制一个文件夹下所有的文件夹到另一个文件夹下 
    //import java.io.*; 
    //import java.util.*; 
    File copyfolders=new File(str1); 
    File[] copyfoldersList=copyfolders.listFiles(); 
    for(int k=0;k<copyfoldersList.length;k++){ 
        if(copyfoldersList[k].isDirectory()){ 
            ArrayList<String>folderList=new ArrayList<String>(); 
            folderList.add(copyfoldersList[k].getPath()); 
            ArrayList<String>folderList2=new ArrayList<String>(); 
            folderList2.add(str2+"/"+copyfoldersList[k].getName()); 
            for(int j=0;j<folderList.length;j++){ 
                 (new File(folderList2.get(j))).mkdirs(); //如果文件夹不存在 则建立新文件夹 
                 File folders=new File(folderList.get(j)); 
                 String[] file=folders.list(); 
                 File temp=null; 
                 try { 
                     for (int i = 0; i < file.length; i++) { 
                         if(folderList.get(j).endsWith(File.separator)){ 
                             temp=new File(folderList.get(j)+"/"+file[i]); 
                         } else { 
                             temp=new File(folderList.get(j)+"/"+File.separator+file[i]); 
                         } 
                         FileInputStream input = new FileInputStream(temp); 
                         if(temp.isFile()){ 
                             FileInputStream input = new FileInputStream(temp); 
                             FileOutputStream output = new FileOutputStream(folderList2.get(j) + "/" + (temp.getName()).toString()); 
                             byte[] b = new byte[5120]; 
                             int len; 
                             while ( (len = input.read(b)) != -1) { 
                                 output.write(b, 0, len); 
                             } 
                             output.flush(); 
                             output.close(); 
                             input.close(); 
                         } 
                         if(temp.isDirectory()){//如果是子文件夹 
                             folderList.add(folderList.get(j)+"/"+file[i]); 
                             folderList2.add(folderList2.get(j)+"/"+file[i]); 
                         } 
                     } 
                 } 
                 catch (Exception e) { 
                     System.out.println("复制整个文件夹内容操作出错"); 
                     e.printStackTrace(); 
                 } 
            } 
        } 
    } 

    //15.移动文件夹 
    //import java.io.*; 
    //import java.util.*; 
    LinkedList<String> folderList = new LinkedList<String>(); 
    folderList.add(str1); 
    LinkedList<String> folderList2 = new LinkedList<String>(); 
    folderList2.add(str2 + str1.substring(str1.lastIndexOf("\"))); 
    while (folderList.size() > 0) { 
        (new File(folderList2.peek())).mkdirs(); // 如果文件夹不存在 则建立新文件夹 
        File folders = new File(folderList.peek()); 
        String[] file = folders.list(); 
        File temp = null; 
        try { 
            for (int i = 0; i < file.length; i++) { 
                if (folderList.peek().endsWith(File.separator)) { 
                    temp = new File(folderList.peek() + File.separator + file[i]); 
                } else { 
                    temp = new File(folderList.peek() + File.separator + file[i]); 
                } 
                if (temp.isFile()) { 
                    FileInputStream input = new FileInputStream(temp); 
                    FileOutputStream output = new FileOutputStream( 
                    folderList2.peek() + File.separator + (temp.getName()).toString()); 
                    byte[] b = new byte[5120]; 
                    int len; 
                    while ((len = input.read(b)) != -1) { 
                        output.write(b, 0, len); 
                    } 
                    output.flush(); 
                    output.close(); 
                    input.close(); 
                    if (!temp.delete()) 
                    System.out.println("删除单个文件操作出错!"); 
                } 
                if (temp.isDirectory()) {// 如果是子文件夹 
                    for (File f : temp.listFiles()) { 
                        if (f.isDirectory()) { 
                            folderList.add(f.getPath()); 
                            folderList2.add(folderList2.peek() + File.separator + f.getName()); 
                        } 
                    } 
                } 
            } 
        } catch (Exception e) { 
            // System.out.println("复制整个文件夹内容操作出错"); 
            e.printStackTrace(); 
        } 
        folderList.removeFirst(); 
        folderList2.removeFirst(); 
    } 
    File f = new File(str1); 
    if (!f.delete()) { 
        for (File file : f.listFiles()) { 
            if (file.list().length == 0) { 
                System.out.println(file.getPath()); 
                file.delete(); 
            } 
        } 
    } 
    //16.移动一个文件夹下所有的文件夹到另一个目录下 
    //import java.io.*; 
    //import java.util.*; 
    File movefolders=new File(str1); 
    File[] movefoldersList=movefolders.listFiles(); 
    for(int k=0;k<movefoldersList.length;k++){ 
        if(movefoldersList[k].isDirectory()){ 
            ArrayList<String>folderList=new ArrayList<String>(); 
            folderList.add(movefoldersList[k].getPath()); 
            ArrayList<String>folderList2=new ArrayList<String>(); 
            folderList2.add(str2+"/"+movefoldersList[k].getName()); 
            for(int j=0;j<folderList.length;j++){ 
                 (new File(folderList2.get(j))).mkdirs(); //如果文件夹不存在 则建立新文件夹 
                 File folders=new File(folderList.get(j)); 
                 String[] file=folders.list(); 
                 File temp=null; 
                 try { 
                     for (int i = 0; i < file.length; i++) { 
                         if(folderList.get(j).endsWith(File.separator)){ 
                             temp=new File(folderList.get(j)+"/"+file[i]); 
                         } 
                         else{ 
                             temp=new File(folderList.get(j)+"/"+File.separator+file[i]); 
                         } 
                         FileInputStream input = new FileInputStream(temp); 
                         if(temp.isFile()){ 
                             FileInputStream input = new FileInputStream(temp); 
                             FileOutputStream output = new FileOutputStream(folderList2.get(j) + "/" + (temp.getName()).toString()); 
                             byte[] b = new byte[5120]; 
                             int len; 
                             while ( (len = input.read(b)) != -1) { 
                                 output.write(b, 0, len); 
                             } 
                             output.flush(); 
                             output.close(); 
                             input.close(); 
                             temp.delete(); 
                         } 
                         if(temp.isDirectory()){//如果是子文件夹 
                             folderList.add(folderList.get(j)+"/"+file[i]); 
                             folderList2.add(folderList2.get(j)+"/"+file[i]); 
                         } 
                     } 
                 } 
                 catch (Exception e) { 
                     System.out.println("复制整个文件夹内容操作出错"); 
                     e.printStackTrace(); 
                 } 
            } 
            movefoldersList[k].delete(); 
        } 
    } 

    //17.以一个文件夹的框架在另一个目录创建文件夹和空文件 
    //import java.io.*; 
    //import java.util.*; 
    boolean b=false;//不创建空文件 
    ArrayList<String>folderList=new ArrayList<String>(); 
    folderList.add(str1); 
    ArrayList<String>folderList2=new ArrayList<String>(); 
    folderList2.add(str2); 
    for(int j=0;j<folderList.length;j++){ 
        (new File(folderList2.get(j))).mkdirs(); //如果文件夹不存在 则建立新文件夹 
        File folders=new File(folderList.get(j)); 
        String[] file=folders.list(); 
        File temp=null; 
        try { 
            for (int i = 0; i < file.length; i++) { 
                if(folderList.get(j).endsWith(File.separator)){ 
                    temp=new File(folderList.get(j)+"/"+file[i]); 
                } 
                else{ 
                    temp=new File(folderList.get(j)+"/"+File.separator+file[i]); 
                } 
                FileInputStream input = new FileInputStream(temp); 
                if(temp.isFile()){ 
                    if (b) temp.createNewFile(); 
                } 
                if(temp.isDirectory()){//如果是子文件夹 
                    folderList.add(folderList.get(j)+"/"+file[i]); 
                    folderList2.add(folderList2.get(j)+"/"+file[i]); 
                } 
            } 
        } 
        catch (Exception e) { 
            System.out.println("复制整个文件夹内容操作出错"); 
            e.printStackTrace(); 
        } 
    } 

    //18.复制文件 
    //import java.io.*; 
     int bytesum = 0; 
     int byteread = 0; 
     File oldfile = new File(str1); 
     try { 
     if (oldfile.exists()) { //文件存在时 
     FileInputStream inStream = new FileInputStream(oldfile); //读入原文件 
     FileOutputStream fs = new FileOutputStream(new File(str2,oldfile.getName())); 
     byte[] buffer = new byte[5120]; 
     int length; 
     while ( (byteread = inStream.read(buffer)) != -1) { 
     bytesum += byteread; //字节数 文件大小 
     System.out.println(bytesum); 
     fs.write(buffer, 0, byteread); 
     } 
     inStream.close(); 
     } 
     } 
     catch (Exception e) { 
     System.out.println("复制单个文件操作出错"); 
     e.printStackTrace(); 
     }  

    //19.复制一个文件夹下所有的文件到另一个目录 
    //import java.io.*; 
    File copyfiles=new File(str1); 
    File[] files=copyfiles.listFiles(); 
    for(int i=0;i<files.length;i++){ 
        if(!files[i].isDirectory()){ 
            int bytesum = 0; 
            int byteread = 0; 
            try { 
                InputStream inStream = new FileInputStream(files[i]); //读入原文件 
                FileOutputStream fs = new FileOutputStream(new File(str2,files[i].getName()); 
                byte[] buffer = new byte[5120]; 
                int length; 
                while ( (byteread = inStream.read(buffer)) != -1) { 
                    bytesum += byteread; //字节数 文件大小 
                    System.out.println(bytesum); 
                    fs.write(buffer, 0, byteread); 
                } 
                inStream.close(); 
            } catch (Exception e) { 
                System.out.println("复制单个文件操作出错"); 
                e.printStackTrace(); 
            } 
        } 
    }  

    //20.提取扩展名 
    String str2=str1.substring(str1.lastIndexOf(".")+1);