Java原生HttpClient的使用详解

提到Java发送HTTP请求，大家首先想到的是用apache的HttpClient，或者squareup的OkHttp。而在Java11之前，原生Java对此的支持还是比较差的，虽然可以HttpURLConnection、URLConnection、Socket等自带的类发送请求，但是操作比较复杂。直到Java11发布，Java本身也自带了HttpClient。自2020年初，我就在开发中广泛使用了这一新特性，感觉使用体验也还可以。现总结成博客，供大家参考。

1.信任证书管理类

package cn.wja.component;
import javax.net.ssl.TrustManager;
import javax.net.ssl.X509TrustManager;
import java.security.cert.X509Certificate;

class MyX509TrustManager implements X509TrustManager {
   @Override
   public void checkClientTrusted(X509Certificate[] x509Certificates, String s)  {
   }

@Override
   public void checkServerTrusted(X509Certificate[] x509Certificates, String s)  {
   }

@Override
   public X509Certificate[] getAcceptedIssuers() {
       return null;
   }

public static TrustManager[] getTrustManagers() {
       TrustManager[] trustAllCertificates = {new MyX509TrustManager()};
       return trustAllCertificates;
   }
}

2.HttpClient类

package cn.wja.component;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLParameters;
import javax.net.ssl.TrustManager;
import java.net.http.HttpClient;
import java.security.KeyManagementException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.time.Duration;

public class MyHttpClient {
   static public HttpClient getClient() throws NoSuchAlgorithmException, KeyManagementException {
       TrustManager[] trustManagers = MyX509TrustManager.getTrustManagers();
       var timeoutInSeconds = 60;
       SSLParameters sslParams = new SSLParameters();
       sslParams.setEndpointIdentificationAlgorithm("");
       SSLContext sc = SSLContext.getInstance("SSL");
       //取消主机名验证
       System.setProperty("jdk.internal.httpclient.disableHostnameVerification", "true");
       sc.init(null, trustManagers, new SecureRandom());
       return HttpClient.newBuilder()
               .connectTimeout(Duration.ofMillis(timeoutInSeconds * 1000))
               .sslContext(sc)
               .sslParameters(sslParams)
               .followRedirects(HttpClient.Redirect.NEVER)
               .version(HttpClient.Version.HTTP_2)
               .build();
   }
}

3.发送请求工具类

package cn.wja.util;

import cn.wja.component.MyHttpClient;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;

import static java.nio.charset.StandardCharsets.UTF_8;

public class HttpUtils {

public static HttpResponse<String> sendGet(String urlStr, String cookieStr) throws Exception {
       HashMap<String, String> hashMap = new HashMap<>();
       hashMap.put("Cookie",cookieStr);
       return sendGet(urlStr,hashMap);
   }

public static HttpResponse<String> sendGet(String urlStr, Map<String,String> headers) throws KeyManagementException, NoSuchAlgorithmException, IOException, InterruptedException {
       HttpClient client = MyHttpClient.getClient();
       HttpRequest.Builder reqBuilder = getReqBuilder(urlStr);
       reqBuilder.GET();
       for (String key:headers.keySet()){
           reqBuilder.header(key, headers.get(key));
       }
       HttpRequest request = reqBuilder.build();
       HttpResponse<String> result = client.send(request, HttpResponse.BodyHandlers.ofString(UTF_8));
       return result;
   }

private static HttpResponse<String> sendPost(String contentType, String urlStr, String bodyStr, String cookieStr) throws Exception {
       HttpClient client = MyHttpClient.getClient();
       HttpRequest.Builder reqBuilder = getReqBuilder(urlStr);
       HttpRequest.BodyPublisher bodyPublisher = HttpRequest.BodyPublishers.ofString(bodyStr);
       reqBuilder.header("Content-Type", contentType)
               .POST(bodyPublisher)
               .header("Cookie", cookieStr);
       HttpRequest request = reqBuilder.build();
       HttpResponse<String> result = client.send(request, HttpResponse.BodyHandlers.ofString(UTF_8));
       return result;
   }

public static HttpResponse<String> sendFormPost(String urlStr, String formStr, String cookieStr) throws Exception {
       return sendPost("application/x-www-form-urlencoded;charset=utf-8", urlStr, formStr, cookieStr);
   }

public static HttpResponse<String> sendJsonPost(String urlStr, String jsonStr, String cookieStr) throws Exception {
       return sendPost("application/json;charset=utf-8", urlStr, jsonStr, cookieStr);
   }

public static HttpRequest.Builder getReqBuilder(String urlStr) {
       return HttpRequest.newBuilder()
               .uri(URI.create(urlStr))
               .header("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:96.0) Gecko/20100101 Firefox/96.0");
   }
}

4.测试

测试表明，通过调用工具类方法，可以直接发送GET请求和带Form表单/Json的POST请求。如果您要发送其他形式的HTTP请求，也可以参照上述代码自行实现。

来源：https://tomcat.blog.csdn.net/article/details/123157836