package cn.com.basic.face.util;
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import java.util.List;
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import java.io.BufferedReader;
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import java.io.File;
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import java.io.FileInputStream;
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import java.io.IOException;
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import java.io.InputStreamReader;
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import java.io.OutputStream;
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import java.io.OutputStreamWriter;
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import java.io.PrintWriter;
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import java.net.HttpURLConnection;
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import java.net.URL;
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import java.net.URLConnection;
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import java.util.ArrayList;
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/**
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* This utility class provides an abstraction layer for sending multipart HTTP
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* POST requests to a web server.
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*
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* @author www.codejava.net
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*/
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public class MultipartUtility {
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private final String boundary;
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private static final String LINE_FEED = "\r\n";
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private HttpURLConnection httpConn;
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private String charset;
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private OutputStream outputStream;
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private PrintWriter writer;
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/**
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* This constructor initializes a new HTTP POST request with content type
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* is set to multipart/form-data
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*
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* @param requestURL
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* @param charset
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* @throws IOException
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*/
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public MultipartUtility(String requestURL, String charset)
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throws IOException {
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this.charset = charset;
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// creates a unique boundary based on time stamp
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boundary = "===" + System.currentTimeMillis() + "===";
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URL url = new URL(requestURL);
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httpConn = (HttpURLConnection) url.openConnection();
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httpConn.setUseCaches(false);
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httpConn.setDoOutput(true); // indicates POST method
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httpConn.setDoInput(true);
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httpConn.setRequestProperty("Content-Type",
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"multipart/form-data; boundary=" + boundary);
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httpConn.setRequestProperty("User-Agent", "CodeJava Agent");
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httpConn.setRequestProperty("Test", "Bonjour");
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outputStream = httpConn.getOutputStream();
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writer = new PrintWriter(new OutputStreamWriter(outputStream, charset),
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true);
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}
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/**
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* Adds a form field to the request
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*
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* @param name field name
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* @param value field value
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*/
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public void addFormField(String name, String value) {
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writer.append("--" + boundary).append(LINE_FEED);
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writer.append("Content-Disposition: form-data; name=\"" + name + "\"")
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.append(LINE_FEED);
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writer.append("Content-Type: text/plain; charset=" + charset).append(
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LINE_FEED);
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writer.append(LINE_FEED);
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writer.append(value).append(LINE_FEED);
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writer.flush();
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}
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/**
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* Adds a upload file section to the request
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*
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* @param fieldName name attribute in <input type="file" name="..." />
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* @param uploadFile a File to be uploaded
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* @throws IOException
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*/
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public void addFilePart(String fieldName, File uploadFile)
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throws IOException {
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String fileName = uploadFile.getName();
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writer.append("--" + boundary).append(LINE_FEED);
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writer.append(
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"Content-Disposition: form-data; name=\"" + fieldName
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+ "\"; filename=\"" + fileName + "\"")
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.append(LINE_FEED);
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writer.append(
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"Content-Type: "
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+ URLConnection.guessContentTypeFromName(fileName))
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.append(LINE_FEED);
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writer.append("Content-Transfer-Encoding: binary").append(LINE_FEED);
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writer.append(LINE_FEED);
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writer.flush();
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FileInputStream inputStream = new FileInputStream(uploadFile);
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byte[] buffer = new byte[4096];
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int bytesRead = -1;
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while ((bytesRead = inputStream.read(buffer)) != -1) {
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outputStream.write(buffer, 0, bytesRead);
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}
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outputStream.flush();
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inputStream.close();
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writer.append(LINE_FEED);
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writer.flush();
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}
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/**
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* Adds a header field to the request.
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*
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* @param name - name of the header field
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* @param value - value of the header field
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*/
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public void addHeaderField(String name, String value) {
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writer.append(name + ": " + value).append(LINE_FEED);
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writer.flush();
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}
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/**
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* Completes the request and receives response from the server.
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*
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* @return a list of Strings as response in case the server returned
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* status OK, otherwise an exception is thrown.
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* @throws IOException
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*/
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public List<String> finish() throws IOException {
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List<String> response = new ArrayList<String>();
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writer.append(LINE_FEED).flush();
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writer.append("--" + boundary + "--").append(LINE_FEED);
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writer.close();
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// checks server's status code first
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int status = httpConn.getResponseCode();
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if (status == HttpURLConnection.HTTP_OK) {
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BufferedReader reader = new BufferedReader(new InputStreamReader(
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httpConn.getInputStream()));
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String line = null;
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while ((line = reader.readLine()) != null) {
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response.add(line);
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}
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reader.close();
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httpConn.disconnect();
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} else {
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throw new IOException("Server returned non-OK status: " + status);
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}
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return response;
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}
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}
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