运行代码时出现以下错误：
java.lang.RuntimeException: An error occured while executing doInBackground()
at android.os.AsyncTask$3.done(AsyncTask.java:299)
at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
at java.util.concurrent.FutureTask.run(FutureTask.java:137)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
at java.lang.Thread.run(Thread.java:864)
Caused by: java.lang.NullPointerException
at libcore.net.UriCodec.encode(UriCodec.java:132)
at java.net.URLEncoder.encode(URLEncoder.java:57)
at com.example.ayushspc.fileupload.MainActivity$BackgroundTask.doInBackground(MainActivity.java:171)
at com.example.ayushspc.fileupload.MainActivity$BackgroundTask.doInBackground(MainActivity.java:107)
at android.os.AsyncTask$2.call(AsyncTask.java:287)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
at java.util.concurrent.FutureTask.run(FutureTask.java:137)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
at java.lang.Thread.run(Thread.java:864)
MainActivity的代码：
package com.example.ayushspc.fileupload;
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.database.Cursor;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Bundle;
import android.provider.MediaStore;
import android.util.Log;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;
import java.io.BufferedWriter;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;
public class MainActivity extends Activity {
EditText editText;
private String text = null;
private int serverResponseCode = 0;
private ProgressDialog dialog = null;
private String upLoadServerUri = null;
private String imagepath = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
editText = (EditText) findViewById(R.id.textbox);
upLoadServerUri = "";
}
public void selectFile(View view) {
Intent intent = new Intent();
intent.setType("*/*");
intent.setAction(Intent.ACTION_GET_CONTENT);
startActivityForResult(Intent.createChooser(intent, "Complete action using"), 1);
text = editText.getText().toString();
text += "/";
Toast.makeText(getApplicationContext(), text, Toast.LENGTH_SHORT).show();
}
public void uploadFile(View view) {
runOnUiThread(new Runnable() {
@Override
public void run() {
Toast.makeText(getApplicationContext(), "Uplaod Started", Toast.LENGTH_SHORT).show();
}
});
new BackgroundTask().execute(imagepath, text);
runOnUiThread(new Runnable() {
@Override
public void run() {
Toast.makeText(getApplicationContext(), text, Toast.LENGTH_SHORT).show();
}
});
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
new BgTask().execute(requestCode, resultCode, data);
}
public String getPath(Uri uri) {
String[] projection = {MediaStore.Images.Media.DATA};
Cursor cursor = managedQuery(uri, projection, null, null, null);
int column_index = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
cursor.moveToFirst();
return cursor.getString(column_index);
}
class BackgroundTask extends AsyncTask<String, Void, Integer> {
@Override
protected Integer doInBackground(String... params) {
String fileuri = params[0];
String filePath = params[1];
HttpURLConnection conn;
DataOutputStream dos;
String lineEnd = "\r\n";
String twoHyphens = "--";
String boundary = "*****";
int bytesRead, bytesAvailable, bufferSize;
byte[] buffer;
int maxBufferSize = 1024 * 1024;
int maxSize = 1024 * 1024;
File sourceFile = new File(fileuri);
final long length = sourceFile.length();
if (length / maxSize > 1) {
dialog.dismiss();
runOnUiThread(new Runnable() {
public void run() {
Toast.makeText(getApplicationContext(), "File Larger than 1MB", Toast.LENGTH_SHORT).show();
}
});
return 0;
}
if (!sourceFile.isFile()) {
dialog.dismiss();
Log.e("uploadFile", "Source File not exist :" + imagepath);
runOnUiThread(new Runnable() {
public void run() {
Toast.makeText(getApplicationContext(), "Source File not exist :", Toast.LENGTH_SHORT).show();
}
});
return 0;
} else {
try {
// open a URL connection to the Servlet
FileInputStream fileInputStream = new FileInputStream(sourceFile);
URL url = new URL(upLoadServerUri);
// Open a HTTP connection to the URL
conn = (HttpURLConnection) url.openConnection();
conn.setDoInput(true); // Allow Inputs
conn.setDoOutput(true); // Allow Outputs
conn.setUseCaches(false); // Don't use a Cached Copy
conn.setRequestMethod("POST");
conn.setRequestProperty("Connection", "Keep-Alive");
conn.setRequestProperty("ENCTYPE", "multipart/form-data");
conn.setRequestProperty("Content-Type", "multipart/form-data;boundary=" + boundary);
conn.setRequestProperty("uploaded_file", fileuri);
HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
httpURLConnection.setRequestMethod("POST");
httpURLConnection.setDoOutput(true);
OutputStream outputStream = httpURLConnection.getOutputStream();
BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream, "UTF-8"));
String data = URLEncoder.encode("file_path", "UTF-8") + "=" + URLEncoder.encode(filePath, "UTF-8");
bufferedWriter.write(data);
bufferedWriter.flush();
bufferedWriter.close();
outputStream.close();
dos = new DataOutputStream(conn.getOutputStream());
dos.writeBytes(twoHyphens + boundary + lineEnd);
dos.writeBytes("Content-Disposition: form-data; name=\"uploaded_file\";filename=\""
+ fileuri + "\"" + lineEnd);
dos.writeBytes(lineEnd);
// create a buffer of maximum size
bytesAvailable = fileInputStream.available();
bufferSize = Math.min(bytesAvailable, maxBufferSize);
buffer = new byte[bufferSize];
// read file and write it into form...
bytesRead = fileInputStream.read(buffer, 0, bufferSize);
while (bytesRead > 0) {
dos.write(buffer, 0, bufferSize);
bytesAvailable = fileInputStream.available();
bufferSize = Math.min(bytesAvailable, maxBufferSize);
bytesRead = fileInputStream.read(buffer, 0, bufferSize);
}
// send multipart form data necesssary after file data...
dos.writeBytes(lineEnd);
dos.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd);
// Responses from the server (code and message)
serverResponseCode = conn.getResponseCode();
final String serverResponseMessage = conn.getResponseMessage();
Log.i("uploadFile", "HTTP Response is : "
+ serverResponseMessage + ": " + serverResponseCode);
if (serverResponseCode == 200) {
runOnUiThread(new Runnable() {
@Override
public void run() {
Toast.makeText(MainActivity.this, "File Upload Complete.", Toast.LENGTH_SHORT).show();
}
});
} else {
runOnUiThread(new Runnable() {
@Override
public void run() {
Toast.makeText(MainActivity.this, serverResponseMessage, Toast.LENGTH_SHORT).show();
}
});
}
//close the streams //
fileInputStream.close();
dos.flush();
dos.close();
} catch (IOException e) {
e.printStackTrace();
}
return serverResponseCode;
} // End else block
}
}
class BgTask extends AsyncTask<Object, Void, Void> {
@Override
protected Void doInBackground(Object... params) {
Integer requestCode = (Integer) params[0];
Integer resultCode = (Integer) params[1];
Intent data = (Intent) params[2];
if (requestCode == 1 && resultCode == RESULT_OK) {
Uri selectedImageUri = data.getData();
imagepath = getPath(selectedImageUri);
}
return null;
}
}
}
它一直在给错误
String data = URLEncoder.encode("file_path", "UTF-8") + "=" + URLEncoder.encode(filePath, "UTF-8");
任何人都可以指出错误是什么，我该怎么做才能纠正它？
答案 0 :(得分：0)
显然，filePath为null。在操作数据之前，请确保您的数据是非空的。