Java文件操作大全

 /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);