java请求POST发送json格式请求

public static String upload(String url){
try {
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost(url);
MultipartEntity reqEntity = new MultipartEntity();
ArrayList<HashMap<String,String>> enclosureList = new ArrayList<HashMap<String, String>>();
for (int i = 0; i <10 ; i++) {
HashMap<String,String> tmpHash = new HashMap<String, String>();
tmpHash.put("name","testfile"+i+".jpg");
tmpHash.put("url","CgAE3FdNSROAVQqrAAD8dT1kf6k929"+i+".jpg");
enclosureList.add(tmpHash);
}

JSONArray enclosure = JSONArray.fromObject(enclosureList);
StringBody enclosure_str = new StringBody(enclosure.toString());
//json格式的请求数据封装
　　　　　　　JSONObject param = new JSONObject();
param.put("bidId","1027228");
param.put("datumId","102");
param.put("enclosure",enclosure.toString());
System.out.println(param.toString());
StringEntity se = new StringEntity(param.toString());
httppost.setEntity(se);
HttpResponse response = httpclient.execute(httppost);
int statusCode = response.getStatusLine().getStatusCode();
if(statusCode == HttpStatus.SC_OK){
System.out.println("服务器正常响应.....");
HttpEntity resEntity = response.getEntity();
　　　　　　　　　　//解析json格式的返回结果
JSONObject json = JSONObject.fromObject(EntityUtils.toString(resEntity).toString());
System.out.println(json.toString());
EntityUtils.consume(resEntity);
}
} catch (Exception e) {
e.printStackTrace();
}
return "";
}