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使用示例圖像上傳任務。堅持錯誤，請給我建議你的意見java.lang.RuntimeException：將圖像上傳到服務器時無法恢復活動
的Java文件
package com.imageupload;
import android.app.Activity;
import java.io.FileInputStream;
import android.app.Activity;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import android.provider.MediaStore;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends Activity {
Button button;
Uri currImageURI;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button = (Button) this.findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent();
intent.setType("image/*");
intent.setAction(Intent.ACTION_GET_CONTENT);
startActivityForResult(Intent.createChooser(intent, "Select Picture"),1);
}
});
}
public void onActivityResult(int requestCode, int resultCode, Intent data) {
if (resultCode == RESULT_OK) {
if (requestCode == 1) {
// currImageURI is the global variable I’m using to hold the content:
currImageURI = data.getData();
System.out.println("Current image Path is ----->" +getRealPathFromURI(currImageURI));
TextView tv_path = (TextView) findViewById(R.id.path);
tv_path.setText(getRealPathFromURI(currImageURI));
doFileUpload();
}
}
}
//Convert the image URI to the direct file system path of the image file
public String getRealPathFromURI(Uri contentUri) {
String [] proj={MediaStore.Images.Media.DATA};
android.database.Cursor cursor = managedQuery(contentUri,
proj, // Which columns to return
null, // WHERE clause; which rows to return (all rows)
null, // WHERE clause selection arguments (none)
null); // Order-by clause (ascending by name)
int column_index = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
cursor.moveToFirst();
return cursor.getString(column_index);
}
private void doFileUpload(){
HttpURLConnection conn = null;
DataOutputStream dos = null;
DataInputStream inStream = null;
String exsistingFileName = currImageURI.toString();
// Is this the place are you doing something wrong.
String lineEnd = "rn";
String twoHyphens = "--";
String boundary = "*****";
int bytesRead, bytesAvailable, bufferSize;
byte[] buffer;
int maxBufferSize = 1*1024*1024;
String responseFromServer = "";
String urlString = "http://nstwebbeta.com/wolftrax/api/?section=inventory&action=image";
try
{
//------------------ CLIENT REQUEST
Log.e("MediaPlayer","Inside second Method");
FileInputStream fileInputStream = new FileInputStream(new File(exsistingFileName));
// open a URL connection to the Servlet
URL url = new URL(urlString);
// Open a HTTP connection to the URL
conn = (HttpURLConnection) url.openConnection();
// Allow Inputs
conn.setDoInput(true);
// Allow Outputs
conn.setDoOutput(true);
// Don't use a cached copy.
conn.setUseCaches(false);
// Use a post method.
conn.setRequestMethod("POST");
conn.setRequestProperty("Connection", "Keep-Alive");
conn.setRequestProperty("Content-Type", "multipart/form-data;boundary="+boundary);
dos = new DataOutputStream(conn.getOutputStream());
dos.writeBytes(twoHyphens + boundary + lineEnd);
dos.writeBytes("Content-Disposition: form-data; name=\"uploadedfile\";filename=\""
+ exsistingFileName + "\"" + lineEnd);
dos.writeBytes(lineEnd);
Log.e("MediaPlayer","Headers are written");
// 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);
// close streams
Log.e("MediaPlayer","File is written");
fileInputStream.close();
dos.flush();
dos.close();
}
catch (MalformedURLException ex)
{
Log.e("MediaPlayer", "error: " + ex.getMessage(), ex);
}
catch (IOException ioe)
{
Log.e("MediaPlayer", "error: " + ioe.getMessage(), ioe);
}
//------------------ read the SERVER RESPONSE
try {
inStream = new DataInputStream (conn.getInputStream());
String str;
while ((str = inStream.readLine()) != null)
{
Log.e("MediaPlayer","Server Response"+str);
}
inStream.close();
}
catch (IOException ioex){
Log.e("MediaPlayer", "error: " + ioex.getMessage(), ioex);
}
}
}
清單文件
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.imageupload" >
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera" />
<uses-feature android:name="android.hardware.camera.autofocus" />
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
LOG
FATAL EXCEPTION: main
java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=1, result=-1, data=Intent { dat=content://media/external/images/media/2795 (has extras) }} to activity {com.imageupload/com.imageupload.MainActivity}: java.lang.NullPointerException
at android.app.ActivityThread.deliverResults(ActivityThread.java:3179)
at android.app.ActivityThread.handleSendResult(ActivityThread.java:3222)
at android.app.ActivityThread.access$1100(ActivityThread.java:140)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1276)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4895)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:994)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:761)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.imageupload.MainActivity.doFileUpload(MainActivity.java:167)
at com.imageupload.MainActivity.onActivityResult(MainActivity.java:56)
at android.app.Activity.dispatchActivityResult(Activity.java:5347)
at android.app.ActivityThread.deliverResults(ActivityThread.java:3175)
at android.app.ActivityThread.handleSendResult(ActivityThread.java:3222)
at android.app.ActivityThread.access$1100(ActivityThread.java:140)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1276)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4895)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:994)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:761)
at dalvik.system.NativeStart.main(Native Method)
第167行是inStream = new DataInputStream（conn.getInputStream（））; 第56行是doFileUpload（）;