通过带有进度条的 MultipartEntityBuilder 通过 HTTP 表单上传文件 [英] Upload a file through an HTTP form, via MultipartEntityBuilder, with a progress bar
问题描述
简短版本 - org.apache...MultipartEntity 已弃用，其升级版 MultipartEntityBuilder 在我们的在线论坛.让我们解决这个问题.如何注册回调，以便我的(Android)应用在上传文件时显示进度条?
The short version - org.apache...MultipartEntity is deprecated, and its upgrade, MultipartEntityBuilder, appears under-represented in our online forums. Let's fix that. How does one register a callback, so my (Android) app can display a progress bar as it uploads a file?
长版本 - 这是 MultipartEntityBuilder 的缺失的简单示例":
The long version - Here's the "missing dirt-simple example" of MultipartEntityBuilder:
public static void postFile(String fileName) throws Exception {
// Based on: https://stackoverflow.com/questions/2017414/post-multipart-request-with-android-sdk
HttpClient client = new DefaultHttpClient();
HttpPost post = new HttpPost(SERVER + "uploadFile");
MultipartEntityBuilder builder = MultipartEntityBuilder.create();
builder.setMode(HttpMultipartMode.BROWSER_COMPATIBLE);
builder.addPart("file", new FileBody(new File(fileName)));
builder.addTextBody("userName", userName);
builder.addTextBody("password", password);
builder.addTextBody("macAddress", macAddress);
post.setEntity(builder.build());
HttpResponse response = client.execute(post);
HttpEntity entity = response.getEntity();
// response.getStatusLine(); // CONSIDER Detect server complaints
entity.consumeContent();
client.getConnectionManager().shutdown();
} // FIXME Hook up a progress bar!
我们需要修复那个FIXME.(一个额外的好处是可以中断上传.)但是(请纠正我，无论我错了)，所有在线示例似乎都不足.
We need to fix that FIXME. (An added benefit would be interruptible uploads.) But (please correct me whether or not I'm wrong), all the online examples seem to fall short.
这个以http://pastebin.com/M0uNZ6SB为例，上传一个文件作为二进制/八位字节流"；不是多部分/表单数据".我需要真实的字段.
This one, http://pastebin.com/M0uNZ6SB, for example, uploads a file as a "binary/octet-stream"; not a "multipart/form-data". I require real fields.
此示例，使用 Java 上传文件(带进度条)，显示如何覆盖 *Entity 或 *Stream.所以也许我可以告诉 MultipartEntityBuilder 到 .create() 一个覆盖其上传进度的实体?
This example, File Upload with Java (with progress bar), shows how to override the *Entity or the *Stream. So maybe I can tell the MultipartEntityBuilder to .create() an overridden entity that meters its upload progress?
因此，如果我想覆盖某些内容，并将内置流替换为每 1000 个字节发送一个信号的计数流，也许我可以扩展 FileBody 部分，并覆盖其 getInputStream 和/或 writeTo.
So if I want to override something, and replace the built-in stream with a counting stream that sends a signal for every 1000 bytes, maybe I can extend the FileBody part, and override its getInputStream and/or writeTo.
但是当我尝试 class ProgressiveFileBody extends FileBody {...} 时，我得到了臭名昭著的 java.lang.NoClassDefFoundError.
But when I try class ProgressiveFileBody extends FileBody {...}, I get the infamous java.lang.NoClassDefFoundError.
所以当我在我的 .jar 文件周围进行探索时，寻找丢失的 Def，有人可以检查我的数学，也许可以指出我忽略的更简单的修复吗?
So while I go spelunking around my .jar files, looking for the missing Def, can someone check my math, and maybe point out a simpler fix I have overlooked?
推荐答案
获奖代码(采用壮观的 Java-Heresy(tm) 风格)是:
The winning code (in spectacular Java-Heresy(tm) style) is:
public static String postFile(String fileName, String userName, String password, String macAddress) throws Exception {
HttpClient client = new DefaultHttpClient();
HttpPost post = new HttpPost(SERVER + "uploadFile");
MultipartEntityBuilder builder = MultipartEntityBuilder.create();
builder.setMode(HttpMultipartMode.BROWSER_COMPATIBLE);
final File file = new File(fileName);
FileBody fb = new FileBody(file);
builder.addPart("file", fb);
builder.addTextBody("userName", userName);
builder.addTextBody("password", password);
builder.addTextBody("macAddress", macAddress);
final HttpEntity yourEntity = builder.build();
class ProgressiveEntity implements HttpEntity {
@Override
public void consumeContent() throws IOException {
yourEntity.consumeContent();
}
@Override
public InputStream getContent() throws IOException,
IllegalStateException {
return yourEntity.getContent();
}
@Override
public Header getContentEncoding() {
return yourEntity.getContentEncoding();
}
@Override
public long getContentLength() {
return yourEntity.getContentLength();
}
@Override
public Header getContentType() {
return yourEntity.getContentType();
}
@Override
public boolean isChunked() {
return yourEntity.isChunked();
}
@Override
public boolean isRepeatable() {
return yourEntity.isRepeatable();
}
@Override
public boolean isStreaming() {
return yourEntity.isStreaming();
} // CONSIDER put a _real_ delegator into here!
@Override
public void writeTo(OutputStream outstream) throws IOException {
class ProxyOutputStream extends FilterOutputStream {
/**
* @author Stephen Colebourne
*/
public ProxyOutputStream(OutputStream proxy) {
super(proxy);
}
public void write(int idx) throws IOException {
out.write(idx);
}
public void write(byte[] bts) throws IOException {
out.write(bts);
}
public void write(byte[] bts, int st, int end) throws IOException {
out.write(bts, st, end);
}
public void flush() throws IOException {
out.flush();
}
public void close() throws IOException {
out.close();
}
} // CONSIDER import this class (and risk more Jar File Hell)
class ProgressiveOutputStream extends ProxyOutputStream {
public ProgressiveOutputStream(OutputStream proxy) {
super(proxy);
}
public void write(byte[] bts, int st, int end) throws IOException {
// FIXME Put your progress bar stuff here!
out.write(bts, st, end);
}
}
yourEntity.writeTo(new ProgressiveOutputStream(outstream));
}
};
ProgressiveEntity myEntity = new ProgressiveEntity();
post.setEntity(myEntity);
HttpResponse response = client.execute(post);
return getContent(response);
}
public static String getContent(HttpResponse response) throws IOException {
BufferedReader rd = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
String body = "";
String content = "";
while ((body = rd.readLine()) != null)
{
content += body + "
";
}
return content.trim();
}
# NOTE ADDED LATER: as this blasterpiece gets copied into various code lineages,
# The management reminds the peanut gallery that "Java-Heresy" crack was there
# for a reason, and (as commented) most of that stuff can be farmed out to off-
# the-shelf jar files and what-not. That's for the java lifers to tool up. This
# pristine hack shall remain obviousized for education, and for use in a pinch.
# What are the odds??
这篇关于通过带有进度条的 MultipartEntityBuilder 通过 HTTP 表单上传文件的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
