How to encode space as %20 in UrlEncodedFormEntity while executing apache HttpPost?

问题

The web serive i am hitting requires the parameters as URLEncodedFormEntity. I am unable to change space to %20 as per requirement of the web service, instead space is converted to +.

My code is :

HttpClient client = new DefaultHttpClient()
HttpPost post = new HttpPost(url);
UrlEncodedFormEntity entity = new UrlEncodedFormEntity(parameters,
            HTTP.UTF_8);
post.setEntity(entity);
HttpResponse resp = client.execute(post);

where parameters is List<NameValuePair> parameters.

I read through many posts and all suggest manuall change space to %20 after emcoding. Here, how do i access the entity and change it manually? Any help will be appreciated.

回答1:

The UrlEncodedFormEntity is basically a StringEntity with a custom constructor, you don't actually have to use it in order to create a usuable entity.

String entityValue = URLEncodedUtils.format(parameters, HTTP.UTF_8);
// Do your replacement here in entityValue
StringEntity entity = new StringEntity(entityValue, HTTP.UTF_8);
entity.setContentType(URLEncodedUtils.CONTENT_TYPE);
// And now do your posting of this entity

回答2:

Jens' answer works like a charm!. To complete his example this what I was using to post a parameter:

String label = "A label";

List<NameValuePair> nvps = new ArrayList<NameValuePair>();

nvps.add(new BasicNameValuePair("label", label));
httpget.setEntity(new UrlEncodedFormEntity(nvps, HTTP.UTF_8));

But it always posts the "+" string, I mean, "label=A+label". Using Jens' suggestion I changed my code to:

String label = "A label";

List<NameValuePair> nvps = new ArrayList<NameValuePair>();

nvps.add(new BasicNameValuePair("label", label));

String entityValue = URLEncodedUtils.format(nvps, HTTP.UTF_8);
entityValue = entityValue.replaceAll("\\+", "%20");

StringEntity stringEntity = new StringEntity(entityValue, HTTP.UTF_8);
stringEntity.setContentType(URLEncodedUtils.CONTENT_TYPE);

httpget.setEntity(stringEntity);

Now it posts "label=A%20label"

来源：https://stackoverflow.com/questions/7915029/how-to-encode-space-as-20-in-urlencodedformentity-while-executing-apache-httppo