我有一个ApiHelper类，用于在我的项目中请求API。我想为分段上传图像提供一种方法。我不知道如何在android中进行multipart的方法。 Volley用于多部分方法。有两种方法类似于需要多部分方法。我正在这里发布我的ApiHelper类。
import android.content.Context;
import android.util.Log;
import com.android.volley.AuthFailureError;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.TimeoutError;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.JsonObjectRequest;
import com.android.volley.toolbox.Volley;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.HashMap;
import java.util.Map;
import static com.android.volley.Request.Method.POST;
/**
* Created by Gourav on 09-02-2017.
*/
public class ApiHelper {
private static ApiHelper mInstance;
private RequestQueue mRequestQueue;
Context context;
ApiHelper(Context context) {
this.context = context;
}
public static synchronized ApiHelper getInstance(Context context) {
if (mInstance == null) {
mInstance = new ApiHelper(context);
}
return mInstance;
}
public RequestQueue getRequestQueue() {
if (mRequestQueue == null) {
// getApplicationContext() is key, it keeps you from leaking the
// Activity or BroadcastReceiver if someone passes one in.
mRequestQueue = Volley.newRequestQueue(context.getApplicationContext());
}
return mRequestQueue;
}
public <T> void addToRequestQueue(Request<T> req) {
getRequestQueue().add(req);
}
public void doGetRequest(String url, final HashMap<String, String> headers, final ApiCallback callback) {
Log.d("url", "" + url);
JsonObjectRequest jsObjRequest = new JsonObjectRequest
(Request.Method.GET, url, null, new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
Log.d("onResponse", "" + response);
try {
callback.onResponse(response);
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Log.d("onErrorResponse", "" + error.getMessage());
callback.onError("Server error");
}
}) {
@Override
public Map<String, String> getHeaders() throws AuthFailureError {
if (headers != null) {
return headers;
} else {
return super.getHeaders();
}
}
};
addToRequestQueue(jsObjRequest);
}
public void doPostRequest(String url, final HashMap<String, String> headers, final JSONObject jsonObject, final ApiCallback callback) {
Log.d("url", "" + url);
Log.d("url", "" + jsonObject.toString());
url = url.replace(" ", "%20");
JsonObjectRequest jsObjRequest = new JsonObjectRequest
(POST, url, jsonObject, new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
Log.d("onResponse", "" + response);
if (response != null) {
try {
callback.onResponse(response);
} catch (JSONException e) {
e.printStackTrace();
}
} else {
callback.onError("Null");
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
error.printStackTrace();
Log.d("onErrorResponse", "" + error.getMessage());
if (error instanceof TimeoutError) {
callback.onError("Timeout bad network");
} else
callback.onError(error.getMessage());
}
}) {
@Override
public Map<String, String> getHeaders() throws AuthFailureError {
if (headers != null) {
return headers;
} else {
return super.getHeaders();
}
}
};
try {
Log.d("headers", "" + jsObjRequest.getHeaders().toString());
} catch (AuthFailureError authFailureError) {
authFailureError.printStackTrace();
}
addToRequestQueue(jsObjRequest);
}
}
创建名为MultipartUtilityPOST.java的新类
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;
public class MultipartUtilityPOST {
private final String boundary;
private static final String LINE_FEED = "\r\n";
private HttpURLConnection httpConn;
private String charset;
private OutputStream outputStream;
private PrintWriter writer;
/**
* This constructor initializes a new HTTP POST request with content type
* is set to multipart/form-data
* @throws IOException
*/
public MultipartUtilityPOST(String requestURL, String charset)
throws IOException {
this.charset = charset;
// creates a unique boundary based on time stamp
boundary = "===" + System.currentTimeMillis() + "===";
URL url = new URL(requestURL);
httpConn = (HttpURLConnection) url.openConnection();
httpConn.setUseCaches(false);
httpConn.setDoOutput(true); // indicates POST method
httpConn.setDoInput(true);
httpConn.setRequestMethod("POST");
httpConn.setRequestProperty("Content-Type",
"multipart/form-data; boundary=" + boundary);
httpConn.setRequestProperty("User-Agent", "CodeJava Agent");
httpConn.setRequestProperty("Test", "Bonjour");
outputStream = httpConn.getOutputStream();
writer = new PrintWriter(new OutputStreamWriter(outputStream, charset),
true);
}
/**
* Adds a form field to the request
*
* @param name field name
* @param value field value
*/
public void addFormField(String name, String value) {
writer.append("--" + boundary).append(LINE_FEED);
writer.append("Content-Disposition: form-data; name=\"" + name + "\"")
.append(LINE_FEED);
writer.append("Content-Type: text/plain; charset=" + charset).append(
LINE_FEED);
writer.append(LINE_FEED);
writer.append(value).append(LINE_FEED);
writer.flush();
}
/**
* Adds a upload file section to the request
*
* @param fieldName name attribute in <input type="file" name="..." />
* @param uploadFile a File to be uploaded
* @throws IOException
*/
public void addFilePart(String fieldName, File uploadFile)
throws IOException {
String fileName = uploadFile.getName();
writer.append("--" + boundary).append(LINE_FEED);
writer.append(
"Content-Disposition: form-data; name=\"" + fieldName
+ "\"; filename=\"" + fileName + "\"")
.append(LINE_FEED);
writer.append(
"Content-Type: "
+ URLConnection.guessContentTypeFromName(fileName))
.append(LINE_FEED);
writer.append("Content-Transfer-Encoding: binary").append(LINE_FEED);
writer.append(LINE_FEED);
writer.flush();
FileInputStream inputStream = new FileInputStream(uploadFile);
byte[] buffer = new byte[4096];
int bytesRead = -1;
while ((bytesRead = inputStream.read(buffer)) != -1) {
outputStream.write(buffer, 0, bytesRead);
}
outputStream.flush();
inputStream.close();
writer.append(LINE_FEED);
writer.flush();
}
/**
* Adds a header field to the request.
*
* @param name - name of the header field
* @param value - value of the header field
*/
public void addHeaderField(String name, String value) {
writer.append(name + ": " + value).append(LINE_FEED);
writer.flush();
}
/**
* Completes the request and receives response from the server.
*
* @return a list of Strings as response in case the server returned
* status OK, otherwise an exception is thrown.
* @throws IOException
*/
public String finish() throws IOException {
StringBuffer response ;
writer.append(LINE_FEED).flush();
writer.append("--" + boundary + "--").append(LINE_FEED);
writer.close();
// checks server's status code first
int status = httpConn.getResponseCode();
if (status == HttpURLConnection.HTTP_OK) {
BufferedReader reader = new BufferedReader(new InputStreamReader(
httpConn.getInputStream()));
String line = null;
response = new StringBuffer();
while ((line = reader.readLine()) != null) {
response.append(line);
}
reader.close();
httpConn.disconnect();
} else {
throw new IOException("Server returned non-OK status: " + status);
}
return response.toString();
}
}
从您想要触发API请求的位置调用addFilePart方法
String charset = "UTF-8";
MultipartUtilityPOST multipart;
try {
multipart = new MultipartUtilityPOST("API URL", charset);
multipart.addFilePart("content", new File(your_file_path));
multipart.addFormField("content_type", "image/jpeg");
String response = multipart.finish();
catch (Exception e)
{
e.printStackTrace();
}