Java HttpClient 发送 POST 请求示例代码

以下是 Java 中使用 HttpClient 库发送一个 POST 请求的示例代码：

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;

import java.io.IOException;

public class PostRequestExample {
    public static void main(String[] args) {
        String url = 'https://example.com/api/post';
        String requestBody = '{"name":"John", "age":30}';

        CloseableHttpClient httpClient = HttpClients.createDefault();
        HttpPost httpPost = new HttpPost(url);
        StringEntity requestEntity = new StringEntity(requestBody, 'UTF-8');
        httpPost.setEntity(requestEntity);

        try (CloseableHttpResponse response = httpClient.execute(httpPost)) {
            HttpEntity entity = response.getEntity();
            String responseString = EntityUtils.toString(entity, 'UTF-8');
            System.out.println(responseString);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

这个示例中，我们首先定义了要请求的 URL 和请求体。然后创建一个 CloseableHttpClient 对象，这个对象负责发送 HTTP 请求和接收 HTTP 响应。接着，我们创建一个 HttpPost 对象，并将请求体设置到请求中。最后，我们使用 httpClient 对象的 execute 方法发送 POST 请求，并使用 response 对象获取响应实体并解析响应内容。最后，我们关闭 httpClient 和 response。