MultipartEntity與UrlEncodedFormEntity

html中的form 表單有兩種：除了傳統的application/x-www-form-urlencoded表單，咱們另外一個常常用到的是上傳文件用的表單，這種表單的類型爲multipart/form-data。  後者主要是用來上傳文件所用，因此通常狀況下，在使用webservice 時，使用UrlEncodedFormEntity 比較多，UrlEncodedFormEntity 能夠模擬傳統的HTML表單傳送POST請求中的參數，

如：html表單以下：

<form action=」http://localhost/index.html」 method=」POST」>
<input type=」text」 name=」param1″ value=」李三」/>
<input type=」text」 name=」param2″ value=」男」/>
<inupt type=」submit」 value=」submit」/>
</form>

 

代碼以下：

List<NameValuePair> formParams = new ArrayList<NameValuePair>();
formParams.add(new BasicNameValuePair(「param1″, 「李三」));
formParams.add(new BasicNameValuePair(「param2″, 「男」));
UrlEncodedFormEntity entity = new UrlEncodedFormEntity(formParams, 「UTF-8″);

MultipartEntity  則與form類型爲multipart/form-data 對應，如 html from 以下：

 

<form action=」http://localhost/index.html」 method=」POST」
enctype=」multipart/form-data」>
<input type=」text」 name=」param1″ value=」李三」/>
<input type=」text」 name=」param2″ value=」男」/>
<input type=」file」 name=」param3″/>
<inupt type=」submit」 value=」submit」/>
</form>

代碼以下：

MultipartEntity entity = new MultipartEntity();
entity.addPart(「param1″, new StringBody(「李三」, Charset.forName(「UTF-8″)));
entity.addPart(「param2″, new StringBody(「男」, Charset.forName(「UTF-8″)));
entity.addPart(「param3″, new FileBody(new File(「C:\\pic.gif」)));

/*
   org.apache.http.entity.mime.content.FileBody.FileBody
   org.apache.http.client.methods.HttpPost.HttpPost
   org.apache.http.entity.mime.MultipartEntityBuilder
   org.apache.http.client.methods.CloseableHttpResponse
   org.apache.http.HttpEntity
*/
CloseableHttpResponse response = null;
HttpEntity entity = null;
String result = null;
try {
	FileBody bin = new FileBody(uploadImgRequest.getFile());
	HttpPost httpPost = new HttpPost(uploadImgRequest.getUrl());
	HttpEntity reqEntity = MultipartEntityBuilder.create()
	.addPart("buffer", bin)
	.addTextBody("access_token", uploadImgRequest.getAccess_token())
	.build();
	httpPost.setEntity(reqEntity);
	response = httpClient.execute(httpPost);
	entity = response.getEntity();
	if (entity != null) {
		result = EntityUtils.toString(entity, "utf-8");
	}
	int statusCode = response.getStatusLine().getStatusCode();
	if (statusCode != 200) {
		httpPost.abort();
		throw new RuntimeException("HttpClient,error status code :"
				+ statusCode+",result:"+result);
	}
}