在过去的几天里，我一直想弄清楚我做错了什么。每当用户上传文件（非图像），并尝试将URI对象转换为文件然后转换为字节数组时，我会收到此错误：
java.io.FileNotFoundException：/ document / 2301（没有这样的文件或目录）
我显然已经上传了一些东西，因为它向我展示了一些路径。这是我的代码：主要活动 -
import android.Manifest;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.graphics.Bitmap;
import android.media.MediaFormat;
import android.net.Uri;
import android.provider.MediaStore;
import android.support.annotation.NonNull;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.widget.ImageView;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (checkSelfPermission(Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
requestPermissions(new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, 1);
} else {
getFile();
}
}
public void getFile() {
Intent intent = new Intent();
intent.setType("application/pdf");
intent.setAction(Intent.ACTION_GET_CONTENT);
startActivityForResult(intent, 1);
}
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
if (requestCode == 1) {
if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
getFile();
}
}
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == 1 && resultCode == RESULT_OK && data != null) {
Uri selectedFile = data.getData();
Log.i("Path", selectedFile.getPath());
File file = new File(selectedFile.getPath());
byte[] b = new byte[(int) file.length()];
try {
FileInputStream fileInputStream = new FileInputStream(file);
fileInputStream.read(b);
for (int i = 0; i < b.length; i++) {
System.out.print((char)b[i]);
}
} catch (FileNotFoundException e) {
System.out.println("File Not Found.");
e.printStackTrace();
}
catch (IOException e1) {
System.out.println("Error Reading The File.");
e1.printStackTrace();
}
}
}
}
感谢任何形式的帮助！
答案 0 :(得分：2)
内部存储上不存在该文件。使用下面的代码来解决问题。
public static String getPath(Context context, Uri uri) {
final boolean isKitKat = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT;
// DocumentProvider
if (isKitKat && DocumentsContract.isDocumentUri(context, uri)) {
// ExternalStorageProvider
if (isExternalStorageDocument(uri)) {
final String docId = DocumentsContract.getDocumentId(uri);
final String[] split = docId.split(":");
final String type = split[0];
if ("primary".equalsIgnoreCase(type)) {
return Environment.getExternalStorageDirectory() + "/" + split[1];
}
// TODO handle non-primary volumes
}
// DownloadsProvider
else if (isDownloadsDocument(uri)) {
final String id = DocumentsContract.getDocumentId(uri);
final Uri contentUri = ContentUris.withAppendedId(Uri.parse("content://downloads/public_downloads"), Long.valueOf(id));
return getDataColumn(context, contentUri, null, null);
}
// MediaProvider
else
if (isMediaDocument(uri)) {
final String docId = DocumentsContract.getDocumentId(uri);
final String[] split = docId.split(":");
final String type = split[0];
Uri contentUri = null;
if ("image".equals(type)) {
contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
} else if ("video".equals(type)) {
contentUri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI;
} else if ("audio".equals(type)) {
contentUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
}
final String selection = "_id=?";
final String[] selectionArgs = new String[] {split[1]};
return getDataColumn(context, contentUri, selection, selectionArgs);
}
}
// MediaStore (and general)
else if ("content".equalsIgnoreCase(uri.getScheme())) {
// Return the remote address
if (isGooglePhotosUri(uri))
return uri.getLastPathSegment();
return getDataColumn(context, uri, null, null);
}
// File
else if ("file".equalsIgnoreCase(uri.getScheme())) {
return uri.getPath();
}
return null;
}
public static String getDataColumn(Context context, Uri uri, String selection, String[] selectionArgs) {
Cursor cursor = null;
final String column = "_data";
final String[] projection = { column };
try {
cursor = context.getContentResolver().query(uri, projection, selection, selectionArgs, null);
if (cursor != null && cursor.moveToFirst()) {
final int index = cursor.getColumnIndexOrThrow(column);
return cursor.getString(index);
}
} finally {
if (cursor != null)
cursor.close();
}
return null;
}
public static boolean isExternalStorageDocument(Uri uri) {
return "com.android.externalstorage.documents".equals(uri.getAuthority());
}
/**
* @param uri The Uri to check.
* @return Whether the Uri authority is DownloadsProvider.
*/
public static boolean isDownloadsDocument(Uri uri) {
return "com.android.providers.downloads.documents".equals(uri.getAuthority());
}
/**
* @param uri The Uri to check.
* @return Whether the Uri authority is MediaProvider.
*/
public static boolean isMediaDocument(Uri uri) {
return "com.android.providers.media.documents".equals(uri.getAuthority());
}
/**
* @param uri The Uri to check.
* @return Whether the Uri authority is Google Photos.
*/
public static boolean isGooglePhotosUri(Uri uri) {
return "com.google.android.apps.photos.content".equals(uri.getAuthority());
}
使用以下代码以任何格式浏览文件。
public void browseClick() {
Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
intent.setType("*/*");
intent.addCategory(Intent.CATEGORY_OPENABLE);
//intent.putExtra("browseCoa", itemToBrowse);
//Intent chooser = Intent.createChooser(intent, "Select a File to Upload");
try {
//startActivityForResult(chooser, FILE_SELECT_CODE);
startActivityForResult(Intent.createChooser(intent, "Select a File to Upload"),FILE_SELECT_CODE);
} catch (Exception ex) {
System.out.println("browseClick :"+ex);//android.content.ActivityNotFoundException ex
}
}
然后在onActivityResult中获取该文件路径，如下所示。
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == FILE_SELECT_CODE) {
if (resultCode == RESULT_OK) {
try {
Uri uri = data.getData();
if (filesize >= FILE_SIZE_LIMIT) {
Toast.makeText(this,"The selected file is too large. Selet a new file with size less than 2mb",Toast.LENGTH_LONG).show();
} else {
String mimeType = getContentResolver().getType(uri);
if (mimeType == null) {
String path = getPath(this, uri);
if (path == null) {
filename = FilenameUtils.getName(uri.toString());
} else {
File file = new File(path);
filename = file.getName();
}
} else {
Uri returnUri = data.getData();
Cursor returnCursor = getContentResolver().query(returnUri, null, null, null, null);
int nameIndex = returnCursor.getColumnIndex(OpenableColumns.DISPLAY_NAME);
int sizeIndex = returnCursor.getColumnIndex(OpenableColumns.SIZE);
returnCursor.moveToFirst();
filename = returnCursor.getString(nameIndex);
String size = Long.toString(returnCursor.getLong(sizeIndex));
}
File fileSave = getExternalFilesDir(null);
String sourcePath = getExternalFilesDir(null).toString();
try {
copyFileStream(new File(sourcePath + "/" + filename), uri,this);
} catch (Exception e) {
e.printStackTrace();
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
private void copyFileStream(File dest, Uri uri, Context context)
throws IOException {
InputStream is = null;
OutputStream os = null;
try {
is = context.getContentResolver().openInputStream(uri);
os = new FileOutputStream(dest);
byte[] buffer = new byte[1024];
int length;
while ((length = is.read(buffer)) > 0) {
os.write(buffer, 0, length);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
is.close();
os.close();
}
}
在此之后，您可以从应用程序外部存储中打开此文件，并使用适当的操作保存文件。
答案 1 :(得分：1)
private String fileToBase64Conversion(Uri file) {
InputStream inputStream = null;//You can get an inputStream using any IO API
ByteArrayOutputStream output = new ByteArrayOutputStream();
try {
inputStream = context.getContentResolver().openInputStream(file);
byte[] buffer = new byte[8192];
int bytesRead;
Base64OutputStream outputBase64 = new Base64OutputStream(output, Base64.DEFAULT);
try {
while ((bytesRead = inputStream.read(buffer)) != -1) {
outputBase64.write(buffer, 0, bytesRead);
}
} catch (IOException e) {
e.printStackTrace();
}
outputBase64.close();
} catch (Exception ex) {
}
return outputBase64.toString();
}