每天认识几个maven依赖（HTTPClient+abbot）-优快云博客

本文链接：https://blog.youkuaiyun.com/m0_63783672/article/details/141683425

Maven

中心仓库网站：Central Repository: (apache.org)

一、HTTPClient

1、是什么？

HttpClient 是Apache Jakarta Common 下的子项目，可以用来提供高效的、最新的、功能丰富的支持 HTTP 协议的客户端编程工具包，并且它支持 HTTP 协议最新的版本和建议。

2、有什么用？

发送 HTTP 请求和接收 HTTP 响应的类

3、怎么学？

创建对象。
创建请求方法的实例，并指定请求URL。（HttpGet/HttpPost）
如果需要发送请求参数，可调用HttpGet、HttpPost共同的setParams(HttpParams params)方法来添加请求参数；对于HttpPost对象而言，也可调用setEntity(HttpEntity entity)方法来设置请求参数。
调用HttpClient对象的execute(HttpUriRequest request)发送请求，该方法返回一个HttpResponse。
调用HttpResponse的getAllHeaders()、getHeaders(String name)等方法可获取服务器的响应头。
调用HttpResponse的getEntity()方法可获取HttpEntity对象，该对象包装了服务器的响应内容。程序可通过该对象获取服务器的响应内容。
释放连接。无论执行方法是否成功，都必须释放连接

实例

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;

import java.io.IOException;

public class HttpClientExample {
    public static void main(String[] args) {
        // 创建 HttpClient 实例
        try (CloseableHttpClient httpClient = HttpClients.createDefault()) {
            // 创建 HttpGet 请求实例
            HttpGet httpGet = new HttpGet("https://www.baidu.com");

            // 发送请求并获取响应
            try (CloseableHttpResponse response = httpClient.execute(httpGet)) {
                // 获取响应体
                String responseBody = EntityUtils.toString(response.getEntity());

                // 打印响应体
                System.out.println(responseBody);
            } catch (IOException e) {
                e.printStackTrace();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

HTTPClientUtils

public class HttpClientUtils {
    // 静态常量和变量声明
    private static final int MAX_TOTAL_CONN = 600;
    private static final int MAX_CONN_PER_HOST = 300;
    private static final int SOCKET_TIMEOUT = 5000;
    private static final int CONNECTION_TIMEOUT = 200;
    private static final int CONNECTION_MANAGER_TIMEOUT = 100;

    private static CloseableHttpClient httpclient;
    private static PoolingHttpClientConnectionManager connMrg;
    private static String encoding = StandardCharsets.UTF_8.name();
    private static Logger log = LoggerFactory.getLogger(HttpClientUtils.class);
    private static final ScheduledExecutorService scheduledService = Executors.newScheduledThreadPool(2);

    // 静态代码块，用于初始化 HttpClient 和连接管理器，并设置 JVM 退出时关闭 HttpClient
    static {
        init();
        destroyByJvmExit();
    }

    // 初始化连接管理器和 HttpClient
    private static void init() {
        connMrg = new PoolingHttpClientConnectionManager();
        connMrg.setMaxTotal(MAX_TOTAL_CONN);
        connMrg.setDefaultMaxPerRoute(MAX_CONN_PER_HOST);

        httpclient = HttpClients.custom()
                .setConnectionManager(connMrg)
                .setDefaultRequestConfig(HttpClientUtils.defaultRequestConfig())
                .build();

        // 定时任务，定期清理过期和空闲连接
        scheduledService.scheduleAtFixedRate(() -> {
            connMrg.closeExpiredConnections();
            connMrg.closeIdleConnections(CONNECTION_MANAGER_TIMEOUT, TimeUnit.MILLISECONDS);
        }, 0, CONNECTION_MANAGER_TIMEOUT, TimeUnit.MILLISECONDS);
    }

    // JVM 退出时关闭 HttpClient
    private static void destroyByJvmExit() {
        Runtime.getRuntime().addShutdownHook(new Thread(() -> {
            try {
                httpclient.close();
            } catch (IOException e) {
                log.error("Error closing HttpClient: {}", e.getMessage());
            }
        }));
    }

    // 创建 HttpClientContext
    private static HttpClientContext createContext() {
        return HttpClientContext.create();
    }

    // 创建默认的 RequestConfig
    private static RequestConfig defaultRequestConfig() {
        return RequestConfig.custom()
                .setConnectTimeout(CONNECTION_TIMEOUT)
                .setSocketTimeout(SOCKET_TIMEOUT)
                .setConnectionRequestTimeout(CONNECTION_MANAGER_TIMEOUT)
                .build();
    }

    // 发起带参数的 POST 表单请求，返回字符串结果
    public static String postWithParamsForString(String url, List<NameValuePair> params) {
        HttpPost httpPost = new HttpPost();
        try {
            URI uri = new URIBuilder(url).build();
            httpPost.setURI(uri);
            httpPost.setEntity(new UrlEncodedFormEntity(params, StandardCharsets.UTF_8));

            return executeRequest(httpPost);
        } catch (URISyntaxException | IOException e) {
            log.error("Error executing POST request: {}", e.getMessage());
        } finally {
            httpPost.releaseConnection();
        }
        return null;
    }
    
    // 发起 GET 请求，返回字符串结果
    public static String get(String url, List<NameValuePair> params) {
        HttpGet httpGet = new HttpGet();
        try {
            URI uri = new URIBuilder(url).setParameters(params).build();
            httpGet.setURI(uri);

            return executeRequest(httpGet);
        } catch (URISyntaxException | IOException e) {
            log.error("HTTP GET request failed", e);
        } finally {
            httpGet.releaseConnection();
        }
        return null;
    }

    // 发起 Post 请求，返回字符串结果
    public static String post(String url, String json) {
        HttpPost httpPost = new HttpPost();
        try {
            httpPost.setURI(new URI(url));
            httpPost.setHeader("Content-Type", "application/json");
            httpPost.setEntity(new StringEntity(json));
            return executeRequest(httpPost);
        } catch (UnsupportedEncodingException e) {
            log.error("Unsupported encoding for JSON entity", e);
        } catch (URISyntaxException | IOException e) {
            log.error("HTTP POST request failed", e);
        } finally {
            httpPost.releaseConnection();
        }
        return null;
    }

    // 执行 HTTP 请求并处理响应
    private static String executeRequest(HttpUriRequest request) throws IOException {
        try (CloseableHttpResponse response = httpclient.execute(request, createContext())) {
            int statusCode = response.getStatusLine().getStatusCode();
            if (statusCode == HttpStatus.SC_OK) {
                HttpEntity entity = response.getEntity();
                if (entity != null) {
                    return EntityUtils.toString(entity, encoding);
                } else {
                    log.warn("Empty response entity");
                }
            } else {
                log.error("HTTP request failed with status code: {}", statusCode);
            }
        } catch (IOException e) {
            log.error("HTTP request execution failed: {}", e.getMessage());
            throw e;
        }
        return null;
    }
}