Java发application/x-www-form-urlencoded请求

[java]代码库

//依赖
<dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpmime</artifactId>
            <version>4.5.6</version>
</dependency>

public static String httpPost(String url, String contentType, Map<String, String> param) {
        CloseableHttpClient httpClient = HttpClients.createDefault();
        HttpPost httpPost = new HttpPost(url);
        try {
            httpPost.setHeader("Content-Type", contentType);

            List<NameValuePair> list = new ArrayList<>();
            for (String key : param.keySet()) {
                list.add(new NameValuePair() {
                    @Override
                    public String getName() {
                        return key;
                    }

                    @Override
                    public String getValue() {
                        return param.get(key);
                    }
                });
            }
            httpPost.setEntity(new UrlEncodedFormEntity(list, StandardCharsets.UTF_8));
            // 执行发送请求,并获取返回值
            CloseableHttpResponse response = httpClient.execute(httpPost);

            HttpEntity entity2 = response.getEntity();
            String result = "";
            if (entity2 != null) {
                result = EntityUtils.toString(entity2, Charset.defaultCharset());
                System.out.println("response_length: " + entity2.getContentLength());
                System.out.println("response: " + result);
            }
            return result;
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }