java 如何在 Http POST 请求中发送图像文件？（爪哇）
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How do I send an image file in a Http POST request? (java)
提问by Nige
So I'm writing a small app to dump a directory of images into the user's tumblr blog, using their provided API: http://www.tumblr.com/docs/en/api
所以我正在编写一个小应用程序，使用他们提供的 API 将图像目录转储到用户的 tumblr 博客中：http: //www.tumblr.com/docs/en/api
I've gotten plaintext posting to work, but now I need to find out how to send an image file in the POST instead of UTF-8 encoded text, and I'm lost. My code at the moment is returning a 403 forbidden error, as if the username and password were incorrect (they're not), and everything else I try gives me a bad request error. I'd rather not have to use external libraries for this if I can. This is my ImagePost class:
我已经开始使用纯文本发布，但现在我需要找出如何在 POST 中发送图像文件而不是 UTF-8 编码文本，但我迷路了。我的代码目前返回 403 禁止错误，好像用户名和密码不正确（它们不是），而我尝试的所有其他操作都给我一个错误的请求错误。如果可以，我宁愿不必为此使用外部库。这是我的 ImagePost 类：
public class ImagePost {
String data = null;
String enc = "UTF-8";
String type;
File img;
public ImagePost(String imgPath, String caption, String tags) throws IOException {
//Construct data
type = "photo";
img = new File(imgPath);
data = URLEncoder.encode("email", enc) + "=" + URLEncoder.encode(Main.getEmail(), enc);
data += "&" + URLEncoder.encode("password", enc) + "=" + URLEncoder.encode(Main.getPassword(), enc);
data += "&" + URLEncoder.encode("type", enc) + "=" + URLEncoder.encode(type, enc);
data += "&" + URLEncoder.encode("data", enc) + "=" + img;
data += "&" + URLEncoder.encode("caption", enc) + "=" + URLEncoder.encode(caption, enc);
data += "&" + URLEncoder.encode("generator", "UTF-8") + "=" + URLEncoder.encode(Main.getVersion(), "UTF-8");
data += "&" + URLEncoder.encode("tags", "UTF-8") + "=" + URLEncoder.encode(tags, "UTF-8");
}
public void send() throws IOException {
// Set up connection
URL tumblrWrite = new URL("http://www.tumblr.com/api/write");
HttpURLConnection http = (HttpURLConnection) tumblrWrite.openConnection();
http.setDoOutput(true);
http.setRequestMethod("POST");
http.setRequestProperty("Content-Type", "image/png");
DataOutputStream dout = new DataOutputStream(http.getOutputStream());
//OutputStreamWriter out = new OutputStreamWriter(http.getOutputStream());
// Send data
http.connect();
dout.writeBytes(data);
//out.write(data);
dout.flush();
System.out.println(http.getResponseCode());
System.out.println(http.getResponseMessage());
dout.close();
}
}
回答by thomelicious
I suggest you use MultipartRequestEntity(successor of deprecated MultipartPostMethod) of the Apache httpclientpackage. With MultipartRequestEntityyou can send a multipart POST request including a file. An example is below:
我建议您使用Apache包MultipartRequestEntity（已弃用的后继者MultipartPostMethod）httpclient。随着MultipartRequestEntity您可以发送一个多POST请求包括文件。一个例子如下：
public static void postData(String urlString, String filePath) {
log.info("postData");
try {
File f = new File(filePath);
PostMethod postMessage = new PostMethod(urlString);
Part[] parts = {
new StringPart("param_name", "value"),
new FilePart(f.getName(), f)
};
postMessage.setRequestEntity(new MultipartRequestEntity(parts, postMessage.getParams()));
HttpClient client = new HttpClient();
int status = client.executeMethod(postMessage);
} catch (HttpException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
