我正在编写一个应用程序，让用户可以选择手机上已有的照片并将其上传到服务器。不幸的是，当我单击按钮将照片发送到服务器时，在 logcat 中我看到：
Could not find class 'org.apache.http.entity.mime.MultipartEntity', referenced from method com.example.crescentcameraapp.MainActivity$ImageUploadTask.doInBackground
我已经看到堆栈溢出中存在的所有类似问题：
还有一些，但关键是，它们都没有一个好的答案。解决方案包括：
“从http://hc.apache.org/downloads.cgi下载所有必要的 jar ，并将它们添加到 Eclipse 中的 Java 构建路径。” ** 不起作用。我已经尝试过了，清理了项目，关闭/打开了 Eclipse。没有什么。
“将所有 jars 添加到项目中的 libs 文件夹中，其余的由 Android 完成。” **仍然，它不起作用。我不知道为什么。
出于某种原因，即使它将此错误发布到 logcat，它仍会继续运行，并且稍后当我尝试使用我在代码中创建的 MultiPartEntity 对象时才会崩溃。这是 logcat 的其余部分：
06-17 21:21:34.396: E/dalvikvm(14917): Could not find class 'org.apache.http.entity.mime.MultipartEntity', referenced from method com.example.crescentcameraapp.MainActivity$ImageUploadTask.doInBackground
06-17 21:21:34.396: W/dalvikvm(14917): VFY: unable to resolve new-instance 652 (Lorg/apache/http/entity/mime/MultipartEntity;) in Lcom/example/crescentcameraapp/MainActivity$ImageUploadTask;
06-17 21:21:34.396: D/dalvikvm(14917): VFY: replacing opcode 0x22 at 0x002b
06-17 21:21:34.396: I/dalvikvm(14917): DexOpt: unable to optimize static field ref 0x0422 at 0x2d in Lcom/example/crescentcameraapp/MainActivity$ImageUploadTask;.doInBackground
06-17 21:21:34.396: D/dalvikvm(14917): DexOpt: unable to opt direct call 0x10e8 at 0x2f in Lcom/example/crescentcameraapp/MainActivity$ImageUploadTask;.doInBackground
06-17 21:21:34.396: D/dalvikvm(14917): DexOpt: unable to opt direct call 0x10eb at 0x56 in Lcom/example/crescentcameraapp/MainActivity$ImageUploadTask;.doInBackground
06-17 21:21:34.396: D/dalvikvm(14917): DexOpt: unable to opt direct call 0x10eb at 0x62 in Lcom/example/crescentcameraapp/MainActivity$ImageUploadTask;.doInBackground
06-17 21:21:34.396: D/dalvikvm(14917): DexOpt: unable to opt direct call 0x10ea at 0x6e in Lcom/example/crescentcameraapp/MainActivity$ImageUploadTask;.doInBackground
06-17 21:21:34.396: D/dalvikvm(14917): DexOpt: unable to opt direct call 0x10eb at 0x85 in Lcom/example/crescentcameraapp/MainActivity$ImageUploadTask;.doInBackground
06-17 21:21:34.401: W/dalvikvm(14917): threadid=11: thread exiting with uncaught exception (group=0x412192a0)
06-17 21:21:34.406: E/AndroidRuntime(14917): FATAL EXCEPTION: AsyncTask #1
06-17 21:21:34.406: E/AndroidRuntime(14917): java.lang.RuntimeException: An error occured while executing doInBackground()
06-17 21:21:34.406: E/AndroidRuntime(14917): at android.os.AsyncTask$3.done(AsyncTask.java:299)
06-17 21:21:34.406: E/AndroidRuntime(14917): at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
06-17 21:21:34.406: E/AndroidRuntime(14917): at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
06-17 21:21:34.406: E/AndroidRuntime(14917): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
06-17 21:21:34.406: E/AndroidRuntime(14917): at java.util.concurrent.FutureTask.run(FutureTask.java:137)
06-17 21:21:34.406: E/AndroidRuntime(14917): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
06-17 21:21:34.406: E/AndroidRuntime(14917): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
06-17 21:21:34.406: E/AndroidRuntime(14917): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
06-17 21:21:34.406: E/AndroidRuntime(14917): at java.lang.Thread.run(Thread.java:856)
06-17 21:21:34.406: E/AndroidRuntime(14917): Caused by: java.lang.NoClassDefFoundError: org.apache.http.entity.mime.MultipartEntity
06-17 21:21:34.406: E/AndroidRuntime(14917): at com.example.crescentcameraapp.MainActivity$ImageUploadTask.doInBackground(MainActivity.java:244)
06-17 21:21:34.406: E/AndroidRuntime(14917): at com.example.crescentcameraapp.MainActivity$ImageUploadTask.doInBackground(MainActivity.java:1)
06-17 21:21:34.406: E/AndroidRuntime(14917): at android.os.AsyncTask$2.call(AsyncTask.java:287)
06-17 21:21:34.406: E/AndroidRuntime(14917): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
06-17 21:21:34.406: E/AndroidRuntime(14917): ... 5 more
06-17 21:21:43.731: I/Choreographer(14917): Skipped 534 frames! The application may be doing too much work on its main thread.
06-17 21:21:44.856: E/WindowManager(14917): Activity com.example.crescentcameraapp.MainActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@41c93710 that was originally added here
06-17 21:21:44.856: E/WindowManager(14917): android.view.WindowLeaked: Activity com.example.crescentcameraapp.MainActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@41c93710 that was originally added here
还有更多，但你明白了。下面是相关代码。ImageUploadTask 是一个内部类：
class ImageUploadTask extends AsyncTask <Void, Void, String>{
@SuppressWarnings("deprecation")
@Override
protected String doInBackground(Void... unsued) {
try {
HttpClient httpClient = new DefaultHttpClient();
HttpContext localContext = new BasicHttpContext();
HttpPost httpPost = new HttpPost(
getString(R.string.web_url_text)
+ "/test.php"
);
MultipartEntity entity = new MultipartEntity(
HttpMultipartMode.BROWSER_COMPATIBLE);
ByteArrayOutputStream bos = new ByteArrayOutputStream();
imageBMP.compress(CompressFormat.JPEG, 100, bos);
byte[] data = bos.toByteArray();
entity.addPart("photoId", new StringBody(getIntent()
.getStringExtra("photoId")));
entity.addPart("returnformat", new StringBody("json"));
entity.addPart("uploaded", new ByteArrayBody(data,
"myImage.jpg"));
String captionText = findViewById(R.string.caption_text).toString();
entity.addPart("photoCaption", new StringBody(captionText));
httpPost.setEntity(entity);
HttpResponse response = httpClient.execute(httpPost,
localContext);
BufferedReader reader = new BufferedReader(
new InputStreamReader(
response.getEntity().getContent(), "UTF-8"));
String sResponse = reader.readLine();
return sResponse;
} catch (Exception e) {
if (dialog.isShowing())
dialog.dismiss();
Toast.makeText(getApplicationContext(),
"Error sending file to server...",
Toast.LENGTH_LONG).show();
Log.e(e.getClass().getName(), e.getMessage(), e);
return null;
}//end of catch
}
protected void onPostExecute(String sResponse) {
Toast.makeText(getApplicationContext(), "Upload completed.", Toast.LENGTH_LONG).show();
}//onPostExecute()
}//end of class ImageUploadTask
谢谢。