java调用http接口

在Java中，你可以使用各种库来调用HTTP接口，例如Apache HttpClient，OkHttp，Java原生库等。下面是一个使用Apache HttpClient的简单示例：

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

public class Main {
    public static void main(String[] args) throws Exception {
        CloseableHttpClient httpClient = HttpClients.createDefault();
        try {
            HttpGet httpGet = new HttpGet("http://example.com");
            CloseableHttpResponse response = httpClient.execute(httpGet);
            try {
                System.out.println(response.getStatusLine());
                HttpEntity entity = response.getEntity();
                // do something useful with the response body
                // and ensure it is fully consumed
                EntityUtils.consume(entity);
            } finally {
                response.close();
            }
        } finally {
            httpClient.close();
        }
    }
}

这个例子会向 "<http://example.com>" 发送一个GET请求，并打印出返回的状态行。请将 "<http://example.com>" 替换为你想要请求的URL。注意，这是一个同步请求，如果你需要异步请求，你需要使用 AsyncHttpClient 和 Future<HttpResponse>。

如果你想使用OkHttp，你可以参考以下示例：

import okhttp3.*;

public class Main {
    public static void main(String[] args) throws Exception {
        OkHttpClient client = new OkHttpClient();
        Request request = new Request.Builder()
          .url("http://example.com")
          .build();
        try (Response response = client.newCall(request).execute()) {
            System.out.println(response.body().string());
        }
    }
}

在这个例子中，我们创建了一个OkHttpClient并发送了一个GET请求。与Apache HttpClient相比，OkHttp的API更简洁，易用。