Android-----File(文件各种操作)

在Android编程中，操作文件是基本的必备技能，现在做一个操作文件的小工具：DocumentTool.java

代码如下：

 package com.hs.example.exampleapplication.ToolUtil;

 import android.app.Activity;
 import android.content.Context;
 import android.content.pm.PackageManager;
 import android.content.res.AssetManager;
 import android.os.Environment;
 import android.support.v4.app.ActivityCompat;
 import android.text.TextUtils;
 import android.util.Log;

 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.io.RandomAccessFile;

 /**
  * Created by 98426 on 2019/4/17.
  */

 public class DocumentTool {

     /**
      * 【动态申请SD卡读写的权限】
      * Android6.0之后系统对权限的管理更加严格了，不但要在AndroidManifest中添加，还要在应用运行的时候动态申请
      * **/
     private static final int REQUEST_EXTERNAL_STORAGE =  ;
     private static String[] PERMISSON_STORAGE = {"android.permission.READ_EXTERNAL_STORAGE",
             "android.permission.WRITE_EXTERNAL_STORAGE"};
     public static void verifyStoragePermissions(Activity activity){
         try {
             int permission = ActivityCompat.checkSelfPermission(activity,"android.permission.WRITE_EXTERNAL_STORAGE");
             if(permission!= PackageManager.PERMISSION_GRANTED){/**【判断是否已经授予权限】**/
                 ActivityCompat.requestPermissions(activity,PERMISSON_STORAGE,REQUEST_EXTERNAL_STORAGE);
             }
         }catch (Exception e){
             e.printStackTrace();
         }
     }

     /**【检查文件目录是否存在，不存在就创建新的目录】**/
     public static void checkFilePath(File file ,boolean isDir){
         if(file!=null){
             if(!isDir){     //如果是文件就返回父目录
                 file = file.getParentFile();
             }
             if(file!=null && !file.exists()){
                 file.mkdirs();
             }
         }
     }

     /**【创建一个新的文件夹】**/
     public static void addFolder(String folderName){
         try {
             if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
                 File sdCard = Environment.getExternalStorageDirectory();
                 File newFolder = new File(sdCard + File.separator + folderName);
                 if(!newFolder.exists()){
                     boolean isSuccess = newFolder.mkdirs();
                     Log.i("TAG:","文件夹创建状态--->" + isSuccess);
                 }
                 Log.i("TAG:","文件夹所在目录：" + newFolder.toString());
             }
         }catch (Exception e){
             e.printStackTrace();
         }
     }

     /**【创建文件】**/
     public static void addFile(String fileName){
         if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
             try {
                 File sdCard = Environment.getExternalStorageDirectory();
                 File newFile = new File(sdCard.getCanonicalPath()+File.separator+"testFolder/"+fileName);
                 if(!newFile.exists()){
                     boolean isSuccess = newFile.createNewFile();
                     Log.i("TAG:","文件创建状态--->"+isSuccess);
                     Log.i("TAG:","文件所在路径："+newFile.toString());
                     deleteFile(newFile);
                 }
             }catch (Exception e){
                 e.printStackTrace();
             }
         }
     }

     /**【删除文件】**/
     public static void deleteFile(File file){
         if(file.exists()){                          //判断文件是否存在
             if(file.isFile()){                      //判断是否是文件
                 boolean isSucess = file.delete();
                 Log.i("TAG:","文件删除状态--->" + isSucess);
             }else if(file.isDirectory()){           //判断是否是文件夹
                 File files[] = file.listFiles();    //声明目录下所有文件
                 for (int i=;i<files.length;i++){   //遍历目录下所有文件
                     deleteFile(files[i]);           //把每个文件迭代删除
                 }
                boolean isSucess = file.delete();
                 Log.i("TAG:","文件夹删除状态--->" + isSucess);
             }
         }
     }

     /**【重写数据到文件】**/
     public static void writeData(String path , String fileData){
         try {
             if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
                 File file = new File(path);
                 FileOutputStream out = new FileOutputStream(file,false);
                 out.write(fileData.getBytes("UTF-8"));              //将数据写入到文件中
                 Log.i("TAG:","将数据写入到文件中："+fileData);
                 out.close();
             }
         }catch (Exception e){
             e.printStackTrace();
         }
     }

     /**【续写数据到文件】**/
     public static void writtenFileData(String path , String data){
         try {
             if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
                 File file = new File(path);
                 RandomAccessFile raf = new RandomAccessFile(file,"rw");  //按读写方式
                 raf.seek(file.length());                                        //将文件指针移到文件尾
                 raf.write(data.getBytes("UTF-8"));                //将数据写入到文件中
                 Log.i("TAG:","要续写进去的数据：" + data);
                 raf.close();
             }
         }catch (Exception e){
             e.printStackTrace();
         }
     }

     /**【读取文件内容】**/
     public static String readFileContent(String path){
         try {
             if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
                 File file = new File(path);
                 byte [] buffer = new byte[*];
                 FileInputStream fis = new FileInputStream(file);
                 int len = ;
                 StringBuffer sb = new StringBuffer("");
                 while((len=fis.read(buffer))>){
                     sb.append(new String(buffer,,len));
                 }
                 fis.close();
                 return sb.toString();
             }
         }catch (Exception e){
             e.printStackTrace();
         }
         return null;
     }

     /**【判断文件是否存在】**/
     public static boolean isFileExists(String fileName){
         File file = new File(fileName);
         return file.exists();
     }

     /**【判断文件夹是否存在】**/
     public static boolean isFolderExists(String directoryPath){
         if(TextUtils.isEmpty(directoryPath)){
             return false;
         }
         File dire = new File(directoryPath);
         return (dire.exists() && dire.isDirectory());  //如果是文件夹并且文件夹存在则返回true
     }

     /**【获取文件夹名称】**/
     public static String getFolderName(String folderName){
         if(TextUtils.isEmpty(folderName)){
             return folderName;
         }
         int filePosi = folderName.lastIndexOf(File.separator);
         return (filePosi == - ) ? "" : folderName.substring( , filePosi);
     }

     /**【重命名文件】**/
     public static boolean renameFile(String oldFileName , String newFileName){
         File oldName = new File(oldFileName);
         File newName = new File(newFileName);
         return oldName.renameTo(newName);
     }

     /**【判断文件夹里是否有文件】**/
     public static boolean hasFileExists(String folderPath){
         File file = new File(folderPath);
         if(file.exists()){
             File [] files = file.listFiles();
             if(files.length>){
                 return true;
             }
         }
         return false;
     }

     /**【复制文件】参数为：String **/
     public static int copyFile(String fromFile , String toFile){
         try {
             InputStream fosfrom = new FileInputStream(fromFile);
             OutputStream outto = new FileOutputStream(toFile);
             byte[] bt = new byte[];
             int len = fosfrom.read(bt);
             if(len > ){
                 outto.write(bt,,len);
             }
             fosfrom.close();
             outto.close();
             return ;
         }catch (Exception e){
             e.printStackTrace();
             return -;
         }
     }
     /**【复制文件】参数为：File  **/
     public static int copyFile(File formFile , File toFile){
         try {
             InputStream forform = new FileInputStream(formFile);
             OutputStream forto = new FileOutputStream(toFile);
             byte [] bt = new byte[];
             int len = forform.read(bt);
             if(len > ){
                 forto.write(bt,,len);
             }
             forform.close();
             forto.close();
             return ;
         }catch (Exception e){
             e.printStackTrace();
             return -;
         }
     }
     /**【复制文件】使用：AssetManager  **/
     public static void copyFileFormAsset(Context context,String assetFile , String toFilePath){
         if(!new File(toFilePath).exists()){
             try {
                 AssetManager assetManager = context.getAssets();
                 InputStream is = assetManager.open(assetFile);
                 OutputStream os = new FileOutputStream(new File(toFilePath));
                 byte [] bt = new byte[];
                 int len = ;
                 while ((is.read(bt))>){        //循环从输入流读取
                     os.write(bt,,len);     //将读取到的输入流写到输出流
                 }
                 is.close();
                 os.close();
             }catch (Exception e){
                 e.printStackTrace();
             }
         }
     }

     /**【复制文件夹】**/
     public static int copyDir(String fromFolder , String toFolder){
         File [] currentFiles;
         File root = new File(fromFolder);
         if(!root.exists()){                     //如果文件不存在就返回出去
             return -;
         }
         currentFiles = root.listFiles();        //存在则获取当前目录下的所有文件
         File targetDir = new File(toFolder);    //目标目录
         if(!targetDir.exists()){                //不存在就创建新目录
             targetDir.mkdirs();
         }
         for(int i=;i<currentFiles.length;i++){ //遍历currentFiles下的所有文件
             if(currentFiles[i].isDirectory()){  //如果当前目录为子目录
                 copyDir(currentFiles[i].getPath() + "/" , currentFiles[i].getName()+"/");  /**进行当前函数递归操作**/
             }else{                              //当前为文件，则进行文件拷贝
                 copyFile(currentFiles[i].getPath() , toFolder + currentFiles[i].getName());
             }
         }
         return ;
     }

 }

接下来直接调用以上方法就可以了：

 public class MainActivity extends AppCompatActivity implements View.OnClickListener{

 　　Button  btn_file ;

 　　@Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);

         /**【动态申请sdCard读写权限】**/
         DocumentTool.verifyStoragePermissions(MainActivity.this);

         btn_file = this.findViewById(R.id.btn_file);
         btn_file.setOnClickListener(this);

     }

 　　 @Override
     public void onClick(View view) {
         int id = view.getId();
         switch (id){
             case R.id.btn_file:
                 File_i_u_d_s();
                 break;
         }
     }

 /**【操作文件的方法】**/
     private void File_i_u_d_s(){
         DocumentTool tool = new DocumentTool();

         /**【新建文件夹】**/
        /* String folderName = "testFolder";
         tool.addFolder(folderName);*/

         /**【新建文件】**/
         /*tool.addFile("testFile2");*/

         /**【重写数据到文件下面】**/
         /*String path ="/storage/emulated/0/testFolder/testFile";
         String data ="123456789";
         tool.writeData(path,data);*/

         /**【续写数据到文件中】**/
         /*String path ="/storage/emulated/0/testFolder/testFile";
         String data ="000";
         tool.writtenFileData(path,data);*/

         /**【读取文件中的数据】**/
        /* String path ="/storage/emulated/0/testFolder/testFile";
         String data = tool.readFileContent(path);
         Log.i("TAG:","文件中拿到的数据："+data);*/

        String path = Environment.getExternalStorageDirectory().toString();
        Toast.makeText(this, path, Toast.LENGTH_SHORT).show();

     }
 }    

运行结果就不发上来了，如有更好改进方法欢迎留言指正。