构造函数 UrlEncodedFormEntity(List<NameValuePair>, String) 在构建发布请求时出现未定义错误答案

【问题标题】：The constructor UrlEncodedFormEntity(List<NameValuePair>, String) is undefined error in building post request构造函数 UrlEncodedFormEntity(List<NameValuePair>, String) 在构建发布请求时出现未定义错误
【发布时间】：2017-04-11 05:15:19
【问题描述】：

当我在这一行设置我的实体时，我正在尝试使用Apache HTTP components 在 java 中发出 post 请求

httppost.setEntity(new UrlEncodedFormEntity(params, "UTF-8"));

上面写着

“构造函数 UrlEncodedFormEntity(List, String) 未定义”，我不知道为什么。

这是我的全部代码

@Component
public class ScheduledTasks {

@Scheduled(cron="0 9 1-7 * 1 *")    //first monday of each month, at 9am
public void dataLoaderTask() throws Exception   {
    HttpClient httpclient = HttpClients.createDefault();
    HttpPost httppost = new HttpPost("https://erudite-master-api-awsmaui.lab.expts.net/erudite/search");
        List<NameValuePair> params = new ArrayList<NameValuePair>(3);
            params.add(new NameValuePair("action", "count"));
            params.add(new NameValuePair("fields", "Status"));
            params.add(new NameValuePair("filters", ""));
        httppost.setEntity(new UrlEncodedFormEntity(params, "UTF-8"));

            //Execute and get the response.
            HttpResponse response = httpclient.execute(httppost);
            HttpEntity entity = response.getEntity();
            if (entity != null) {
                InputStream instream = entity.getContent();
                try {
                    // do something useful
                } finally {
                    instream.close();
                }
            }
    }

我搜索过的每个资源都表明这是这样做的正确方法，所以我不确定它为什么返回未定义。

【问题讨论】：

标签： java apache http post

【解决方案1】：

可能存在冲突的 Apache HTTP 组件 JAR 文件。我尝试了下面的代码，没有编译错误：这些是类路径中使用的两个 JAR 文件：http-client-4.5.3.jar、http-core-4.4.6.jar。使用 spring-boot 将确保您的存储库中的开源 JAR 文件是最新版本。

@Scheduled(cron = "0 9 1-7 * 1 *") // first monday of each month, at 9am
public void dataLoaderTask() throws Exception {
    CloseableHttpClient httpclient = HttpClients.createDefault();
    HttpPost httppost = new HttpPost("https://erudite-master-api-awsmaui.lab.expts.net/erudite/search");
    List<NameValuePair> params = new ArrayList<NameValuePair>(3);
    params.add(new BasicNameValuePair("action", "count"));
    params.add(new BasicNameValuePair("fields", "Status"));
    params.add(new BasicNameValuePair("filters", ""));
    httppost.setEntity(new UrlEncodedFormEntity(params, "UTF-8"));
    // Execute and get the response.
    CloseableHttpResponse response = httpclient.execute(httppost);
    HttpEntity entity = response.getEntity();
    if (entity != null) {
        InputStream instream = entity.getContent();
        try {
            // do something useful
        } finally {
            instream.close();
        }
    }
}

【讨论】：