收集整理的java常见文件操作，方便平时使用：
//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
//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 folderList = new LinkedList(); folderList.add(str1); while (folderList.size() > 0) { File file = new File(folderList.peek()); folderList.removeLast(); File[] files = file.listFiles(); ArrayList fileList = new ArrayList(); 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 folderList = new LinkedList(); folderList.add(str1); LinkedList folderList2 = new LinkedList(); 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
//15.移动文件夹 //import java.io.*; //import java.util.*; LinkedList folderList = new LinkedList(); folderList.add(str1); LinkedList folderList2 = new LinkedList(); 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
//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 ArrayListfolderList=new ArrayList(); folderList.add(str1); ArrayListfolderList2=new ArrayList(); folderList2.add(str2); for(int j=0;j
//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
//20.提取扩展名 String str2=str1.substring(str1.lastIndexOf(".")+1);