String param = "value";
File textFile = new File("/path/to/file.txt");
File binaryFile = new File("/path/to/file.bin");
String boundary = Long.toHexString(System.currentTimeMillis()); // Just generate some unique random value.
String CRLF = "\r\n"; // Line separator required by multipart/form-data.
URLConnection connection = new URL(url).openConnection();
connection.setDoOutput(true);
connection.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + boundary);
PrintWriter writer = null;
try {
OutputStream output = connection.getOutputStream();
writer = new PrintWriter(new OutputStreamWriter(output, charset), true); // true = autoFlush, important!
// Send normal param.
writer.append("--" + boundary).append(CRLF);
writer.append("Content-Disposition: form-data; name=\"param\"").append(CRLF);
writer.append("Content-Type: text/plain; charset=" + charset).append(CRLF);
writer.append(CRLF);
writer.append(param).append(CRLF).flush();
// Send text file.
writer.append("--" + boundary).append(CRLF);
writer.append("Content-Disposition: form-data; name=\"textFile\"; filename=\"" + textFile.getName() + "\"").append(CRLF);
writer.append("Content-Type: text/plain; charset=" + charset).append(CRLF);
writer.append(CRLF).flush();
BufferedReader reader = null;
try {
reader = new BufferedReader(new InputStreamReader(new FileInputStream(textFile), charset));
for (String line; (line = reader.readLine()) != null;) {
writer.append(line).append(CRLF);
}
} finally {
if (reader != null) try { reader.close(); } catch (IOException logOrIgnore) {}
}
writer.flush();
// Send binary file.
writer.append("--" + boundary).append(CRLF);
writer.append("Content-Disposition: form-data; name=\"binaryFile\"; filename=\"" + binaryFile.getName() + "\"").append(CRLF);
writer.append("Content-Type: " + URLConnection.guessContentTypeFromName(binaryFile.getName()).append(CRLF);
writer.append("Content-Transfer-Encoding: binary").append(CRLF);
writer.append(CRLF).flush();
InputStream input = null;
try {
input = new FileInputStream(binaryFile);
byte[] buffer = new byte[1024];
for (int length = 0; (length = input.read(buffer)) > 0;) {
output.write(buffer, 0, length);
}
output.flush(); // Important! Output cannot be closed. Close of writer will close output as well.
} finally {
if (input != null) try { input.close(); } catch (IOException logOrIgnore) {}
}
writer.append(CRLF).flush(); // CRLF is important! It indicates end of binary boundary.
// End of multipart/form-data.
writer.append("--" + boundary + "--").append(CRLF);
} finally {
if (writer != null) writer.close();
}
public void doPost(HttpServletRequest pRequest, HttpServletResponse pResponse)
throws ServletException, IOException {
ServletFileUpload upload = new ServletFileUpload();
try {
FileItemIterator iter = upload.getItemIterator (pRequest);
while (iter.hasNext()) {
FileItemStream item = iter.next();
String fieldName = item.getFieldName();
InputStream stream = item.openStream();
....
stream.close();
}
...
这段代码会展示一张图片
public void doGet (HttpServletRequest pRequest, HttpServletResponse pResponse) throws IOException {
try {
Blob img = (Blob) entity.getProperty(propImg);
pResponse.addHeader ("Content-Disposition", "attachment; filename=abc.png");
pResponse.addHeader ("Cache-Control", "max-age=120");
String enc = "image/png";
pResponse.setContentType (enc);
pResponse.setContentLength (img.getBytes().length);
OutputStream out = pResponse.getOutputStream ();
out.write (img.getBytes());
out.close();
1.您可以使用以下方式将byte[]编码为base64：
http://commons.apache.org/codec/apidocs/org/apache/commons/codec/binary/Base64.html
2.使用HTTP POST请求将该数据发送到AppEngine servlet。
3.配置AppEngine以接受servlet。
4.然后，您可以选择将其保存到Datastore或Blobstore。我更喜欢Blobstore这些事情。
5.在服务器端解码base64字符串。
6.从那时起，您需要将字符串切成较小的部分，并将每个部分写入Blobstore。
以下是一些代码，用于将其写入Blobstore。
byte[] finalImageArray = null;
try {
finalImageArray = Base64.decode(finalImageData.getBytes()); //finalImageData is the string retrieved from the HTTP POST
} catch (Base64DecoderException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
try{
FileService fileService = FileServiceFactory.getFileService();
AppEngineFile file = fileService.createNewBlobFile("image/png");
FileWriteChannel writeChannel = fileService.openWriteChannel(file, true);
int steps = (int) Math.floor(finalImageArray.length/1000);
int current = 0;
for(int i = 0; i < 1000; i++){
writeChannel.write(ByteBuffer.wrap(Arrays.copyOfRange(finalImageArray, current, steps+current)));
current = current + steps;
}
writeChannel.write(ByteBuffer.wrap(Arrays.copyOfRange(finalImageArray, current, finalImageArray.length))); //The reason it's cut up like this is because you can't write the complete string in one go.
writeChannel.closeFinally();
blobKey = fileService.getBlobKey(file);
if(blobKey == null)
blobKey = retryBloBKey(file); //My own method, AppEngine tends to not return the blobKey once a while.
}
catch(Exception e){
logger.log(Level.SEVERE,e.getMessage());
}
return blobKey.getKeyString();
编写一个servlet，在其中使用提供的键检索图像数据。
享受您美丽的代码 :)
//我之所以以二进制形式保存它，是因为这样可以让我有更多选项来操作图像api，您也可以选择将其保存在base64格式中。
List<Integer> drawablesId = new ArrayList<Integer>();
int picIndex=12345;
File sdDir = new File("/sdcard/pictures");
File[] sdDirFiles = sdDir.listFiles();
for(File singleFile : sdDirFiles)
{
Drawable.createFromPath(singleFile.getAbsolutePath());
/ you can create Bitmap from drawable
}
希望这能对您有所帮助。
不确定这是否符合您的要求，但这将以与浏览器提交表单中图像相同的方式提交图像。您需要下载 httmime-4.1.3.jar 并将其作为引用库添加到您的项目中。
Bitmap bm;//whatever bitmap you are trying to send
ByteArrayOutputStream bos = new ByteArrayOutputStream();
bm.compress(CompressFormat.JPEG, 75, bos);
byte[] data = bos.toByteArray();
HttpClient httpClient = new DefaultHttpClient();
HttpPost postRequest = new HttpPost("http://yourwebsite.com/whatever");
ByteArrayBody bab = new ByteArrayBody(data, "image name");
MultipartEntity reqEntity = new MultipartEntity(HttpMultipartMode.BROWSER_COMPATIBLE);
reqEntity.addPart("photo", bab);//"photo" is the name of the field that the image is submitted as.
postRequest.setEntity(reqEntity);
try {
HttpResponse response = httpClient.execute(postRequest);
} catch (ClientProtocolException e) {
Log.e("asdf", e.getMessage(), e);
} catch (IOException e) {
Log.e("asdf", e.getMessage(), e);
}
Android异步Http库提供了一种上传文件到Web服务的方法。我在我的项目中使用它取得了巨大的成功。
听起来你需要一个接受ID参数并返回文件的Web服务方法。你可以将Blob存储在数据库表中，并以ID为索引进行引用。