从android上传图像多部分表单

Question

http://letitripple.org/htmlform.html

这是此html表单创建的请求。（我从chrome开发者工具中获得）

------WebKitFormBoundaryPug6XAUALAUPBR86内容-配置：表单-数据；name=“wp-user-avatars”；filename=“desert.jpg”内容-类型：image/jpeg

 public AppResponse uploadImageFile(String csURL, String csFilePath)
{
    AppResponse appResponse = null;

    HttpURLConnection conn = null;
    DataOutputStream dos = null;
    ByteArrayOutputStream output = null;
    InputStream inStream = null;


    String Url = csURL;
    String existingFileName = csFilePath;


    String lineEnd = "\r\n";
    String twoHyphens = "--";
    String boundary = "WebKitFormBoundaryleA9RIQsQBxW8Cgl";
    int bytesRead, bytesAvailable, bufferSize;
    byte[] buffer;
 //   String reponse_data = null;
    int maxBufferSize = 1 * 1024 * 1024;
  //  String urlString = "YOUR PHP LINK FOR UPLOADING IMAGE";
    try {
        //------------------ CLIENT REQUEST
        // FileInputStream fileInputStream = new FileInputStream(new File(existingFileName) );
        // open a URL connection to the Servlet
        URL url = new URL(Url);
        // 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);

        FileInputStream fileInputStream = new FileInputStream(new File(existingFileName));//You can get an inputStream using any IO API
        byte[] bytes;
        byte[] buffers = new byte[605244];
        int bytesReads;
        output = new ByteArrayOutputStream();


        // Use a post method.
        conn.setRequestMethod("POST");
        conn.setRequestProperty("Connection", "Keep-Alive");

        conn.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + twoHyphens + twoHyphens + boundary);
        //conn.setRequestProperty("attach1", existingFileName);
        dos = new DataOutputStream(conn.getOutputStream());
        dos.writeBytes(twoHyphens + twoHyphens + twoHyphens + boundary + "\r\n");



        dos.writeBytes("Content-Disposition: form-data; name=\"attach1\"; filename=\"profile.jpg\"\n Content-Type: image/jpg\r\n\r\n\r\n"); // uploaded_file_name is the Name of the File to be uploaded

        // 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);
            Log.e("Value", "Writing");

        }

        // send multipart form data necesssary after file data...
        dos.writeBytes(lineEnd);

        dos.writeBytes(twoHyphens + twoHyphens + twoHyphens + boundary + twoHyphens);

        //String strInput = dos.toString();

        int responseCode = conn.getResponseCode();

        String serverResponseMessage = conn.getResponseMessage();


        fileInputStream.close();

        dos.flush();
        dos.close();

        int nResponseCode = conn.getResponseCode();
        inStream = new DataInputStream(conn.getInputStream());

        BufferedReader in = new BufferedReader(new InputStreamReader(inStream));

        String line = "";
        StringBuilder csResult = new StringBuilder("");

        while ((line = in.readLine()) != null) {
            Log.e("Debug", "Server Response " + csResult);
            csResult.append(line);
        }


        appResponse = new AppResponse(nResponseCode, csResult.toString());



    }
    catch (IOException ioe) {
        Log.e("Debug", "error: " + ioe.getMessage(), ioe);
    }


    return appResponse;
}

Answer 1

我们用以下代码构建名为Multipartutility的实用程序类：

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;
import java.util.ArrayList;
import java.util.List;

/**
 * This utility class provides an abstraction layer for sending multipart HTTP
 * POST requests to a web server.
 * @author www.codejava.net
 *
 */
public class MultipartUtility {
    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
     * @param requestURL
     * @param charset
     * @throws IOException
     */
    public MultipartUtility(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.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 List<String> finish() throws IOException {
        List<String> response = new ArrayList<String>();

        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;
            while ((line = reader.readLine()) != null) {
                response.add(line);
            }
            reader.close();
            httpConn.disconnect();
        } else {
            throw new IOException("Server returned non-OK status: " + status);
        }

        return response;
    }
}

这个实用工具类使用java.net.HttpurlConnection类，并遵循RFC1867（基于表单的文件上传在HTML中），使用多部分/表单数据内容类型发出HTTP POST请求，以便将文件上传到给定的URL。它有一个构造函数和三个方法：

1. Multipartutility（String requestURL,String charset）：为给定的请求URL和charset创建此类的新实例。
2. void addFormField（字符串名称、字符串值）：向请求添加常规文本字段。
3. void addHeaderField（字符串名称、字符串值）：向请求添加HTTP头字段。
4. void addFilePart（字符串fieldName，文件uploadFile）：将要上载的文件附加到请求中。
5. list finish():最后必须调用此方法以完成请求并从服务器接收作为字符串列表的响应。

import java.io.File;
import java.io.IOException;
import java.util.List;

/**
 * This program demonstrates a usage of the MultipartUtility class.
 * @author www.codejava.net
 *
 */
public class MultipartFileUploader {

    public static void main(String[] args) {
        String charset = "UTF-8";
        File uploadFile1 = new File("e:/Test/PIC1.JPG");
        File uploadFile2 = new File("e:/Test/PIC2.JPG");
        String requestURL = "http://localhost:8080/FileUploadSpringMVC/uploadFile.do";

        try {
            MultipartUtility multipart = new MultipartUtility(requestURL, charset);

            multipart.addHeaderField("User-Agent", "CodeJava");
            multipart.addHeaderField("Test-Header", "Header-Value");

            multipart.addFormField("description", "Cool Pictures");
            multipart.addFormField("keywords", "Java,upload,Spring");

            multipart.addFilePart("fileUpload", uploadFile1);
            multipart.addFilePart("fileUpload", uploadFile2);

            List<String> response = multipart.finish();

            System.out.println("SERVER REPLIED:");

            for (String line : response) {
                System.out.println(line);
            }
        } catch (IOException ex) {
            System.err.println(ex);
        }
    }
}