Android: openConnection和Content-Length头部

Question

我已经在StackOverflow和谷歌上搜索过了，不幸的是我找不到答案。

我正在尝试通过"openConnection“获取我下载到android应用程序的文件的内容长度。文件下载正常，但我想要一个跟随进度的进度条。

为了达到这个目的，我需要得到content-length。

我的PHP文件中包含的头文件是：

$file_url = 'myfile.pdf';
header('Content-Type: application/octet-stream');
header("Content-Transfer-Encoding: Binary"); 
header('Content-Length: '.filesize($file_url));
header("Content-disposition: attachment; filename=\"" . basename($file_url) . "\""); 
readfile($file_url);

在联机检查HTTP标头时，我得到的结果是：

HTTP/1.1 200 OK =>
Date => Thu, 24 Jul 2014 10:34:04 GMT
Server => Apache/2
X-Powered-By => PHP/5.3.28
Content-Transfer-Encoding => Binary
Content-disposition => attachment; filename="myile.pdf"
Content-Length => 19011079
Vary => Accept-Encoding,User-Agent
Connection => close
Content-Type => application/octet-stream

所以它确实返回了内容长度。

在整个过程中，fileSize int一直为-1，但文件已正确下载到我的下载目录中，所以这不是问题所在。

现在奇怪的是，当我将它直接设置为JPG时，它确实返回了"Content-Length“。以下是JPG的标头

HTTP/1.1 200 OK =>
Date => Thu, 24 Jul 2014 10:51:21 GMT
Server => Apache/2
Last-Modified => Thu, 24 Jul 2014 10:23:40 GMT
ETag => "506eae-10fcec-4feedd9b40300"
Accept-Ranges => bytes
Content-Length => 1113324
Connection => close
Content-Type => image/jpeg

我尝试过的其他方法是直接链接到PDF，它也没有返回内容长度。我已经尝试上传较小的PDF的，在JPG大小的范围内，但没有成功。

Answer 1

我不理解你的que..

在android中，你想获取content-length或者php文件

如果在php文件中，则使用以下代码

  <?php
    $url = 'http://www.google.com';

    print_r(get_headers($url));

    print_r(get_headers($url, 1));
    ?>

试试下面的android java代码，这段代码很适合我。确保使用Apache HttpClient库。而且你不需要手动设置头部，为特定的请求生成头部是http的责任，如果你愿意，你可以改变头部数据。默认设置表头的所有成员字段。这是我的代码

    import org.apache.http.Header;
    import org.apache.http.HttpEntity;
    import org.apache.http.HttpResponse;
    import org.apache.http.client.HttpClient;
    import org.apache.http.client.methods.HttpPost;
    import org.apache.http.entity.mime.HttpMultipartMode;
    import org.apache.http.entity.mime.MultipartEntity;
    import org.apache.http.entity.mime.content.StringBody;
    import org.apache.http.impl.client.DefaultHttpClient;
    import org.apache.http.params.BasicHttpParams;
    import org.apache.http.params.HttpConnectionParams;
    import org.apache.http.params.HttpParams;
    import org.apache.http.util.EntityUtils;

    import validationUtility.Validation;
    import android.app.ProgressDialog;
    import android.content.Intent;
    import android.os.AsyncTask;
    import android.os.Bundle;
    import android.util.Log;
    import android.view.Menu;
    import android.view.MenuItem;
    import android.view.View;
    import android.widget.EditText;
    import android.widget.TextView;
    import android.widget.Toast;

    public class Login extends BaseActivity{
        private TextView tvBreadCrum;
        private static final String TAG = "Login.java";

        /**
         * content declaration
         */

        private EditText etUserName, etPaddwd;
        private TextView tvForgotPass;
        private String uname, passwd;


        @Override
        protected void onCreate(Bundle savedInstanceState) {
            // TODO Auto-generated method stub
            super.onCreate(savedInstanceState,R.layout.activity_login,getApplicationContext());




            /**
             * header field initialization
             */

            tvBreadCrum = (TextView) findViewById(R.id.tv_bread_crumb);


            tvBreadCrum.setText(">> Login");


            /**
             * content initialize
             * 
             */

            etUserName = (EditText) findViewById(R.id.etUserEmail);
            etPaddwd = (EditText) findViewById(R.id.etUserPassword);
            tvForgotPass = (TextView) findViewById(R.id.tvForgotPass);
            tvForgotPass.setOnClickListener(new View.OnClickListener() {

                @Override
                public void onClick(View arg0) {


                    Intent genInquiry=new Intent(getApplicationContext(),ForgotPasswd.class);

                    startActivity(genInquiry);

                }
            });

        }


        @Override
        public void onBackPressed() {
            // TODO Auto-generated method stub
            super.onBackPressed();
            finish();
        }

        @Override
        public boolean onCreateOptionsMenu(Menu menu) {

            /* Inflate the menu; this adds items to the action bar if it is present. */
            getMenuInflater().inflate(R.menu.contact_us, menu);
            return true;
        }

        @Override
        public boolean onOptionsItemSelected(MenuItem item) {
            // Handle action bar item clicks here. The action bar will
            // automatically handle clicks on the Home/Up button, so long
            // as you specify a parent activity in AndroidManifest.xml.
            int id = item.getItemId();
            if (id == R.id.close) {
                Toast.makeText(getApplicationContext(), "Good Bye...",
                        Toast.LENGTH_LONG).show();
                finish();
                return true;
            }
            return super.onOptionsItemSelected(item);
        }

        public void initVariableFields() {

            uname = etUserName.getText().toString();
            passwd = etPaddwd.getText().toString();
        }

        public boolean isValidate() {
            initVariableFields();
            boolean lbIsValid = true;
            if (!Validation.isEmailAddress(etUserName, true)) {
                return lbIsValid = false;
            } else if (!Validation.hasText(etPaddwd, "Please  your password", 5)) {

                return lbIsValid = false;
            }

            return lbIsValid;
        }

        public void reset() {

            etUserName.setText("");
            etPaddwd.setText("");
        }

        public void onSendClick(View view) {

            if (isValidate()) {
                //Toast.makeText(getApplicationContext(), "Clicked", Toast.LENGTH_LONG).show();return;

                new PostDataAsyncTask().execute();
                reset();
            }
        }

        public class PostDataAsyncTask extends AsyncTask<String, String, String> {
            private final ProgressDialog pDialog = new ProgressDialog(Login.this);

            protected void onPreExecute() {

                pDialog.setTitle("Contacting Servers");
                pDialog.setMessage("Login.......");
                pDialog.setIndeterminate(false);
                pDialog.setCancelable(true);
                pDialog.show();

            }

            @Override
            protected void onPostExecute(final String result) {
                if (this.pDialog.isShowing()) {
                    this.pDialog.dismiss();
                }

                runOnUiThread(new Runnable() {

                    public void run() {
                        reset();
                        Toast.makeText(getApplicationContext(), result,
                                Toast.LENGTH_SHORT).show();

                    }
                });

            }

            @Override
            protected String doInBackground(String... arg0) {
                String responseStr = null;
                try {

                    Log.v(TAG, "in Back job: "
                            + "==========================Hello World");

                    String url1 = "http://lsrv.smartnet.cxm/kamleshG/Extra/postContactData/postData.php";
                    // the URL where the file will be posted
                    String postReceiverUrl = url1;

                    Log.v(TAG, "postURL: " + postReceiverUrl);
                    final HttpParams httpParams = new BasicHttpParams();
                    HttpConnectionParams.setConnectionTimeout(httpParams, 3000);
                    // new HttpClient
                    HttpClient httpClient = new DefaultHttpClient(httpParams);

                    // post header
                    HttpPost httpPost = new HttpPost(postReceiverUrl);

                    MultipartEntity reqEntity = new MultipartEntity(
                            HttpMultipartMode.BROWSER_COMPATIBLE);

                    reqEntity.addPart("email", new StringBody(uname));
                    reqEntity.addPart("passwd", new StringBody(passwd));

                    reqEntity.addPart("submitMessage", new StringBody(
                            "AndroidSubmit"));

                    httpPost.setEntity(reqEntity);
                    /* httpPost.setEntity(new UrlEncodedFormEntity(reqEntity)); */

                    // execute HTTP post request
                    HttpResponse response = httpClient.execute(httpPost);
                    System.out.println("Printing Response Header...\n");

                    Header[] headers = response.getAllHeaders();

            //it prints whole header with content-length
                    for (Header header : headers) {
                        Log.v(TAG,"Key : " + header.getName() 
                                           + " ,Value : " + header.getValue());

                    }                   
                    System.out.println("\n Done");
                    HttpEntity resEntity = response.getEntity();

                    if (resEntity != null) {

                        responseStr = EntityUtils.toString(resEntity).trim();

                        Log.v(TAG, "Response: " + responseStr);


                    }
                } catch (Exception e) {
                    Log.e("e.getClass().getName()", "" + e.toString());
                }
                return responseStr;
            }

        }

    }  

尝试此链接http://www.mkyong.com/java/how-to-get-http-response-header-in-java/