MultipartEntity与UrlEncodedFormEntity

html中的form 表单有两种：除了传统的application/x-www-form-urlencoded表单，咱们另外一个常常用到的是上传文件用的表单，这种表单的类型为multipart/form-data。  后者主要是用来上传文件所用，因此通常状况下，在使用webservice 时，使用UrlEncodedFormEntity 比较多，UrlEncodedFormEntity 能够模拟传统的HTML表单传送POST请求中的参数，

如：html表单以下：

<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>

 

代码以下：

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  则与form类型为multipart/form-data 对应，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>

代码以下：

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);
	}
}