java httpclient发送post请求 带参数

可以使用HttpClient类来发送带参数的POST请求。以下是一个简单的示例代码：

import org.apache.http.HttpEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

public class HttpClientExample {
  public static void main(String[] args) throws Exception {
    CloseableHttpClient httpClient = HttpClients.createDefault();
    HttpPost httpPost = new HttpPost("http://example.com/api/post");
    StringEntity entity = new StringEntity("param1=value1&param2=value2");
    httpPost.setEntity(entity);
    httpPost.setHeader("Accept", "application/json");
    httpPost.setHeader("Content-type", "application/x-www-form-urlencoded");
    CloseableHttpResponse response = httpClient.execute(httpPost);
    HttpEntity responseEntity = response.getEntity();
    System.out.println(EntityUtils.toString(responseEntity));
    response.close();
    httpClient.close();
  }
}

在上面的代码中，我们创建了一个`CloseableHttpClient`对象，并使用`HttpPost`类来发送POST请求，请求地址为`http://example.com/api/post`。我们使用`StringEntity`类来封装请求参数，并通过设置请求头来告诉服务器请求内容的类型。最后，我们使用`CloseableHttpResponse`对象获取服务器的响应，并通过`EntityUtils.toString`方法将响应内容转换为字符串。