主要思路：

通過

MultipartEntityBuilder multipartEntityBuilder = MultipartEntityBuilder.create();

生成HttpEntity，然后再設置到HttpPost中。具體實現如下

代碼展示

httpPostForm

    /**
     * 模擬from表單提交
     *
     * @param url         url地址
     * @param paramList       參數
     * @param headers     請求頭
     * @return
     */
    public static JSONObject httpPostForm(String url, HttpEntity httpEntity , Map<String, String> headers) {
        // post請求返回結果
        CloseableHttpClient httpClient = HttpClients.createDefault();
        JSONObject jsonResult = null;
        HttpPost httpPost = new HttpPost(url);
        // 設置請求和傳輸超時時間
        RequestConfig requestConfig = RequestConfig.custom()
                .setSocketTimeout(10000).setConnectTimeout(10000).build();
        httpPost.setConfig(requestConfig);
        if (!headers.isEmpty()) {
            for (Map.Entry<String, String> entry : headers.entrySet()) {
                httpPost.setHeader(entry.getKey(), entry.getValue());
            }
        }
        try {
            if (null != paramList ) {
                // 解決中文亂碼問題
                httpPost.setEntity(paramList);
            }
            CloseableHttpResponse result = httpClient.execute(httpPost);
            String resultString = EntityUtils.toString(result.getEntity(), "utf-8");
            logger.info(result);
            //請求發送成功，并得到響應
                try {
                    //把json字符串轉換成json對象
                    jsonResult = JSONObject.parseObject(resultString);
                } catch (Exception e) {
                    logger.error("post請求提交失敗:" + url, e);
                }
        } catch (IOException e) {
            logger.error("post請求提交失敗:" + url, e);
        } finally {
            httpPost.releaseConnection();
        }
        return jsonResult;
    }

參數調用方式

        MultipartEntityBuilder multipartEntityBuilder = MultipartEntityBuilder.create();
        //當需要傳入list結構的表單數據的時候直接重名即可，如下面的“to”
        multipartEntityBuilder.addPart("to", new StringBody("A", ContentType.TEXT_PLAIN));
        multipartEntityBuilder.addPart("to", new StringBody("B", ContentType.TEXT_PLAIN));
        multipartEntityBuilder.addPart("cc", new StringBody("C", ContentType.TEXT_PLAIN)); 
        HttpEntity build = multipartEntityBuilder.build();
        JSONObject jsonObject = HttpUtil.httpPostForm( "www.baidu.com", build, header);