【Java - 框架 - HttpClient 5】(01) HttpClient 5 使用详细教程，代码示例 - 快速上手

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HttpClient 5 使用详细教程，代码示例 - 快速上手

依赖

【Maven依赖】

<!-- https://mvnrepository.com/artifact/org.apache.httpcomponents.client5/httpclient5 -->
<dependency>
    <groupId>org.apache.httpcomponents.client5</groupId>
    <artifactId>httpclient5</artifactId>
    <version>5.1.3</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.httpcomponents.client5/httpclient5-fluent -->
<dependency>
    <groupId>org.apache.httpcomponents.client5</groupId>
    <artifactId>httpclient5-fluent</artifactId>
    <version>5.1.3</version>
</dependency>

示例

GET请求

【代码】

01

说明

• 类名；

HttpClient5Get.java

02

import java.io.IOException;

import org.apache.hc.client5.http.classic.methods.HttpGet;
import org.apache.hc.client5.http.impl.classic.CloseableHttpClient;
import org.apache.hc.client5.http.impl.classic.CloseableHttpResponse;
import org.apache.hc.client5.http.impl.classic.HttpClients;
import org.apache.hc.core5.http.HttpEntity;
import org.apache.hc.core5.http.ParseException;
import org.apache.hc.core5.http.io.entity.EntityUtils;

public class HttpClient5Get {

    public static void main(String[] args) {
        String result = get("http://httpbin.org/get");
        System.out.println(result);
    }

    public static String get(String url) {
        String resultContent = null;
        HttpGet httpGet = new HttpGet(url);
        try (CloseableHttpClient httpclient = HttpClients.createDefault()) {
            try (CloseableHttpResponse response = httpclient.execute(httpGet)) {
                // 获取状态码
                System.out.println(response.getVersion()); // HTTP/1.1
                System.out.println(response.getCode()); // 200
                System.out.println(response.getReasonPhrase()); // OK
                HttpEntity entity = response.getEntity();
                // 获取响应信息
                resultContent = EntityUtils.toString(entity);
            }
        } catch (IOException | ParseException e) {
            e.printStackTrace();
        }
        return resultContent;
    }

}

【结果】

01

Fluent GET

【说明】

• 使用"Apache HttpClient 5"提供的"Fluent API"可以更便捷的发起"GET"请求，但是可操作的地方较少；
• 只需要"<artifactId>httpclient5-fluent</artifactId>"依赖即可运行；

【代码】

01

说明

• 类名；

HttpClient5GetFluent.java

02

import java.io.IOException;

import org.apache.hc.client5.http.fluent.Request;
import org.apache.hc.client5.http.fluent.Response;


public class HttpClient5GetFluent {

    public static void main(String[] args) {
        System.out.println(get("http://httpbin.org/get"));
    }

    public static String get(String url) {
        String result = null;
        try {
            Response response = Request.get(url).execute();
            result = response.returnContent().asString();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return result;
    }

}

【结果】

GET 请求参数

【说明】

• 使用 URIBuilder 的 addParameters() 方法来构建"GET"请求的参数；

【代码】

01

说明

• 类名；

HttpClient5GetParams.java

02

import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.ArrayList;
import java.util.List;

import org.apache.hc.client5.http.classic.methods.HttpGet;
import org.apache.hc.client5.http.impl.classic.CloseableHttpClient;
import org.apache.hc.client5.http.impl.classic.CloseableHttpResponse;
import org.apache.hc.client5.http.impl.classic.HttpClients;
import org.apache.hc.core5.http.HttpEntity;
import org.apache.hc.core5.http.NameValuePair;
import org.apache.hc.core5.http.ParseException;
import org.apache.hc.core5.http.io.entity.EntityUtils;
import org.apache.hc.core5.http.message.BasicNameValuePair;
import org.apache.hc.core5.net.URIBuilder;

public class HttpClient5GetParams {

    public static void main(String[] args) {
        String result = get("http://httpbin.org/get");
        System.out.println(result);
    }

    public static String get(String url) {
        String resultContent = null;
        HttpGet httpGet = new HttpGet(url);
        // 表单参数
        List<NameValuePair> nvps = new ArrayList<>();
        // GET 请求参数
        nvps.add(new BasicNameValuePair("username", "SUNxRUN"));
        nvps.add(new BasicNameValuePair("password", "12345678"));
        // 增加到请求 URL 中
        try {
            URI uri = new URIBuilder(new URI(url))
                    .addParameters(nvps)
                    .build();
            httpGet.setUri(uri);
        } catch (URISyntaxException e) {
            throw new RuntimeException(e);
        }

        try (CloseableHttpClient httpclient = HttpClients.createDefault()) {
            try (CloseableHttpResponse response = httpclient.execute(httpGet)) {
                // 获取状态码
                System.out.println(response.getVersion()); // HTTP/1.1
                System.out.println(response.getCode()); // 200
                System.out.println(response.getReasonPhrase()); // OK
                HttpEntity entity = response.getEntity();
                // 获取响应信息
                resultContent = EntityUtils.toString(entity);
            }
        } catch (IOException | ParseException e) {
            e.printStackTrace();
        }
        return resultContent;
    }
}

【结果】

POST 请求

【说明】

• 参数：“username=SUNxRUN&password=12345678”；

【代码】

01

说明

• 类名；

HttpClient5Post.java

02

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import org.apache.hc.client5.http.classic.methods.HttpPost;
import org.apache.hc.client5.http.entity.UrlEncodedFormEntity;
import org.apache.hc.client5.http.impl.classic.CloseableHttpClient;
import org.apache.hc.client5.http.impl.classic.CloseableHttpResponse;
import org.apache.hc.client5.http.impl.classic.HttpClients;
import org.apache.hc.core5.http.HttpEntity;
import org.apache.hc.core5.http.NameValuePair;
import org.apache.hc.core5.http.ParseException;
import org.apache.hc.core5.http.io.entity.EntityUtils;
import org.apache.hc.core5.http.message.BasicNameValuePair;

public class HttpClient5Post {

    public static void main(String[] args) {
        String result = post("http://httpbin.org/post");
        System.out.println(result);
    }

    public static String post(String url) {
        String result = null;
        HttpPost httpPost = new HttpPost(url);
        // 表单参数
        List<NameValuePair> nvps = new ArrayList<>();
        // POST 请求参数
        nvps.add(new BasicNameValuePair("username", "SUNxRUN"));
        nvps.add(new BasicNameValuePair("password", "12345678"));
        httpPost.setEntity(new UrlEncodedFormEntity(nvps));
        try (CloseableHttpClient httpclient = HttpClients.createDefault()) {
            try (CloseableHttpResponse response = httpclient.execute(httpPost)) {
                System.out.println(response.getVersion()); // HTTP/1.1
                System.out.println(response.getCode()); // 200
                System.out.println(response.getReasonPhrase()); // OK

                HttpEntity entity = response.getEntity();
                // 获取响应信息
                result = EntityUtils.toString(entity);
                // 确保流被完全消费
                EntityUtils.consume(entity);
            }
        } catch (IOException | ParseException e) {
            e.printStackTrace();
        }
        return result;
    }

}

【结果】

Fluent POST

【说明】

• 使用"Apache HttpClient 5"提供的"Fluent API"可以更便捷的发起"POST"请求，但是可操作的地方较少；
• 参数：“username=SUNxRUN&password=12345678”；

【代码】

01

说明

• 类名；

HttpClient5PostFluent.java

02

import java.io.IOException;

import org.apache.hc.client5.http.fluent.Request;
import org.apache.hc.core5.http.message.BasicNameValuePair;

public class HttpClient5PostFluent {

    public static void main(String[] args) {
        String result = post("http://httpbin.org/post");
        System.out.println(result);
    }

    public static String post(String url) {
        String result = null;
        Request request = Request.post(url);
        // POST 请求参数
        request.bodyForm(
                new BasicNameValuePair("username", "SUNxRun"),
                new BasicNameValuePair("password", "12345678"));
        try {
            result = request.execute().returnContent().asString();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return result;
    }
}

【结果】

POST JSON 参数

【说明】

• 使用 StringEntity 类存入 JSON 参数；

【代码】

01

说明

• 类名；

HttpClient5PostWithJson.java

02

import java.io.IOException;

import org.apache.hc.client5.http.classic.methods.HttpPost;
import org.apache.hc.client5.http.impl.classic.CloseableHttpClient;
import org.apache.hc.client5.http.impl.classic.CloseableHttpResponse;
import org.apache.hc.client5.http.impl.classic.HttpClients;
import org.apache.hc.core5.http.ContentType;
import org.apache.hc.core5.http.ParseException;
import org.apache.hc.core5.http.io.entity.EntityUtils;
import org.apache.hc.core5.http.io.entity.StringEntity;

public class HttpClient5PostWithJson {

    public static void main(String[] args) {
        String json = "{"
                + "    \"password\": \"121345678\","
                + "    \"username\": \"SUNxRUN\""
                + "}";
        String result = post("http://httpbin.org/post", json);
        System.out.println(result);
    }

    public static String post(String url, String jsonBody) {
        String result = null;
        HttpPost httpPost = new HttpPost(url);
        httpPost.setEntity(new StringEntity(jsonBody, ContentType.APPLICATION_JSON));

        try (CloseableHttpClient httpclient = HttpClients.createDefault()) {
            try (CloseableHttpResponse response = httpclient.execute(httpPost)) {
                // 获取响应信息
                result = EntityUtils.toString(response.getEntity());
            }
        } catch (IOException | ParseException e) {
            e.printStackTrace();
        }
        return result;
    }

}

【结果】

设置超时

【说明】

• 使用 RequestConfig 对象来配置超时时间；

【代码】

01

说明

• 类名；

HttpClient5GetWithTimeout.java

02

import java.io.IOException;

import org.apache.hc.client5.http.classic.methods.HttpGet;
import org.apache.hc.client5.http.config.RequestConfig;
import org.apache.hc.client5.http.impl.classic.CloseableHttpClient;
import org.apache.hc.client5.http.impl.classic.CloseableHttpResponse;
import org.apache.hc.client5.http.impl.classic.HttpClients;
import org.apache.hc.core5.http.HttpEntity;
import org.apache.hc.core5.http.ParseException;
import org.apache.hc.core5.http.io.entity.EntityUtils;
import org.apache.hc.core5.util.Timeout;

public class HttpClient5GetWithTimeout {

    public static void main(String[] args) {
        String result = get("http://httpbin.org/get");
        System.out.println(result);
    }

    public static String get(String url) {
        String resultContent = null;
        // 设置超时时间
        RequestConfig config = RequestConfig.custom()
                .setConnectTimeout(Timeout.ofMilliseconds(5000L))
                .setConnectionRequestTimeout(Timeout.ofMilliseconds(5000L))
                .setResponseTimeout(Timeout.ofMilliseconds(5000L))
                .build();
        // 请求级别的超时
        HttpGet httpGet = new HttpGet(url);
        //httpGet.setConfig(config);
        //try (CloseableHttpClient httpclient = HttpClients.createDefault()) {
        // 客户端级别的超时
        try (CloseableHttpClient httpclient = HttpClients.custom().setDefaultRequestConfig(config).build()) {
            try (CloseableHttpResponse response = httpclient.execute(httpGet)) {
                // 获取状态码
                System.out.println(response.getVersion()); // HTTP/1.1
                System.out.println(response.getCode()); // 200
                System.out.println(response.getReasonPhrase()); // OK
                HttpEntity entity = response.getEntity();
                // 获取响应信息
                resultContent = EntityUtils.toString(entity);
            }
        } catch (IOException | ParseException e) {
            e.printStackTrace();
        }
        return resultContent;
    }

}

异步请求

【代码】

01

说明

• 类名；

HttpClient5Async.java

02

【说明】

• 下面演示三种"HttpClient 5"异步请求方式；

import java.io.IOException;
import java.nio.CharBuffer;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;

import org.apache.hc.client5.http.async.methods.AbstractCharResponseConsumer;
import org.apache.hc.client5.http.async.methods.SimpleHttpRequest;
import org.apache.hc.client5.http.async.methods.SimpleHttpRequests;
import org.apache.hc.client5.http.async.methods.SimpleHttpResponse;
import org.apache.hc.client5.http.impl.async.CloseableHttpAsyncClient;
import org.apache.hc.client5.http.impl.async.HttpAsyncClients;
import org.apache.hc.core5.concurrent.FutureCallback;
import org.apache.hc.core5.http.ContentType;
import org.apache.hc.core5.http.HttpException;
import org.apache.hc.core5.http.HttpResponse;
import org.apache.hc.core5.http.nio.AsyncRequestProducer;
import org.apache.hc.core5.http.nio.support.AsyncRequestBuilder;

public class HttpClient5Async {

    public static void main(String[] args) {
        getAsync1("http://httpbin.org/get");
        getAsync2("http://httpbin.org/get");
        getAsync3("http://httpbin.org/get");
    }

    /**
     * 异步请求
     *
     * @param url
     * @return
     */
    public static String getAsync1(String url) {
        try (CloseableHttpAsyncClient httpclient = HttpAsyncClients.createDefault()) {
            // 开始 http client
            httpclient.start();
            // 执行请求
            SimpleHttpRequest request1 = SimpleHttpRequests.get(url);
            Future<SimpleHttpResponse> future = httpclient.execute(request1, null);
            // 等待直到返回完毕
            SimpleHttpResponse response1 = future.get();
            System.out.println("getAsync1:" + request1.getRequestUri() + "->" + response1.getCode());
        } catch (IOException | ExecutionException | InterruptedException e) {
            throw new RuntimeException(e);
        }
        return null;
    }

    /**
     * 异步请求，根据响应情况回调
     *
     * @param url
     * @return
     */
    public static String getAsync2(String url) {
        try (CloseableHttpAsyncClient httpclient = HttpAsyncClients.createDefault()) {
            // 开始 http client
            httpclient.start();
            // 根据请求响应情况进行回调操作
            CountDownLatch latch = new CountDownLatch(1);
            SimpleHttpRequest request = SimpleHttpRequests.get(url);
            httpclient.execute(request, new FutureCallback<SimpleHttpResponse>() {
                @Override
                public void completed(SimpleHttpResponse response2) {
                    latch.countDown();
                    System.out.println("getAsync2:" + request.getRequestUri() + "->" + response2.getCode());
                }

                @Override
                public void failed(Exception ex) {
                    latch.countDown();
                    System.out.println("getAsync2:" + request.getRequestUri() + "->" + ex);
                }

                @Override
                public void cancelled() {
                    latch.countDown();
                    System.out.println("getAsync2:" + request.getRequestUri() + " cancelled");
                }

            });
            latch.await();
        } catch (IOException | InterruptedException e) {
            throw new RuntimeException(e);
        }
        return null;
    }

    /**
     * 异步请求，对响应流做点什么
     *
     * @param url
     * @return
     */
    public static String getAsync3(String url) {
        try (CloseableHttpAsyncClient httpclient = HttpAsyncClients.createDefault()) {
            // 开始 http client
            httpclient.start();
            // 根据请求响应情况进行回调操作
            SimpleHttpRequest request = SimpleHttpRequests.get(url);

            CountDownLatch latch = new CountDownLatch(1);
            AsyncRequestProducer producer = AsyncRequestBuilder.get("http://httpbin.org/get").build();
            AbstractCharResponseConsumer<HttpResponse> consumer3 = new AbstractCharResponseConsumer<HttpResponse>() {

                HttpResponse response;

                @Override
                protected void start(HttpResponse response, ContentType contentType) throws HttpException, IOException {
                    System.out.println("getAsync3: 开始响应....");
                    this.response = response;
                }

                @Override
                protected int capacityIncrement() {
                    return Integer.MAX_VALUE;
                }

                @Override
                protected void data(CharBuffer data, boolean endOfStream) throws IOException {
                    System.out.println("getAsync3: 收到数据....");
                    // Do something useful
                }

                @Override
                protected HttpResponse buildResult() throws IOException {
                    System.out.println("getAsync3: 接收完毕...");
                    return response;
                }

                @Override
                public void releaseResources() {
                }

            };
            httpclient.execute(producer, consumer3, new FutureCallback<HttpResponse>() {

                @Override
                public void completed(HttpResponse response) {
                    latch.countDown();
                    System.out.println("getAsync3: " + request.getRequestUri() + "->" + response.getCode());
                }

                @Override
                public void failed(Exception ex) {
                    latch.countDown();
                    System.out.println("getAsync3: " + request.getRequestUri() + "->" + ex);
                }

                @Override
                public void cancelled() {
                    latch.countDown();
                    System.out.println("getAsync3: " + request.getRequestUri() + " cancelled");
                }

            });
            latch.await();
        } catch (IOException | InterruptedException e) {
            throw new RuntimeException(e);
        }
        return null;

    }
}

【结果】

获取 Cookie

读取文件内容请求

表单登录

Basic Authorization

Digest Authorization

拦截器

【说明】

• "HttpClient 5"中的拦截器可以对请求过程的各个阶段进行拦截处理；
• 通过 HttpClientBuilder 中的关于 Interceptor 的方法可以看到可以进行拦截的节点；

【代码】

01

说明

• 类名；

HttpClient5Interceptors.java

02

说明

• 下面编写一个示例，发起三次请求，每次请求都在请求头"herader"中增加一个 request-id 参数，然后对 request-id 值为 2 的请求直接响应"404"结束；

import java.io.IOException;
import java.util.concurrent.atomic.AtomicLong;

import org.apache.hc.client5.http.classic.ExecChain;
import org.apache.hc.client5.http.classic.ExecChain.Scope;
import org.apache.hc.client5.http.classic.ExecChainHandler;
import org.apache.hc.client5.http.classic.methods.HttpGet;
import org.apache.hc.client5.http.impl.ChainElement;
import org.apache.hc.client5.http.impl.classic.CloseableHttpClient;
import org.apache.hc.client5.http.impl.classic.CloseableHttpResponse;
import org.apache.hc.client5.http.impl.classic.HttpClients;
import org.apache.hc.core5.http.ClassicHttpRequest;
import org.apache.hc.core5.http.ClassicHttpResponse;
import org.apache.hc.core5.http.ContentType;
import org.apache.hc.core5.http.EntityDetails;
import org.apache.hc.core5.http.Header;
import org.apache.hc.core5.http.HttpException;
import org.apache.hc.core5.http.HttpRequest;
import org.apache.hc.core5.http.HttpRequestInterceptor;
import org.apache.hc.core5.http.HttpStatus;
import org.apache.hc.core5.http.io.entity.EntityUtils;
import org.apache.hc.core5.http.io.entity.StringEntity;
import org.apache.hc.core5.http.message.BasicClassicHttpResponse;
import org.apache.hc.core5.http.protocol.HttpContext;

/**
 * 展示如何在请求和响应时进行拦截进行自定义处理。
 */
public class HttpClient5Interceptors {

    public static void main(final String[] args) throws Exception {
        try (final CloseableHttpClient httpclient = HttpClients.custom()
                // 添加一个请求 id 到请求 header
                .addRequestInterceptorFirst(new HttpRequestInterceptor() {
                    private final AtomicLong count = new AtomicLong(0);

                    @Override
                    public void process(
                            final HttpRequest request,
                            final EntityDetails entity,
                            final HttpContext context) throws HttpException, IOException {
                        request.setHeader("request-id", Long.toString(count.incrementAndGet()));
                    }
                })
                .addExecInterceptorAfter(ChainElement.PROTOCOL.name(), "custom", new ExecChainHandler() {
                    // 请求 id 为 2 的，模拟 404 响应，并自定义响应的内容。
                    @Override
                    public ClassicHttpResponse execute(
                            final ClassicHttpRequest request,
                            final Scope scope,
                            final ExecChain chain) throws IOException, HttpException {

                        final Header idHeader = request.getFirstHeader("request-id");
                        if (idHeader != null && "2".equalsIgnoreCase(idHeader.getValue())) {
                            final ClassicHttpResponse response = new BasicClassicHttpResponse(HttpStatus.SC_NOT_FOUND,
                                    "Oppsie");
                            response.setEntity(new StringEntity("bad luck", ContentType.TEXT_PLAIN));
                            return response;
                        } else {
                            return chain.proceed(request, scope);
                        }
                    }
                })
                .build()) {

            for (int i = 0; i < 3; i++) {
                final HttpGet httpget = new HttpGet("http://httpbin.org/get");

                try (final CloseableHttpResponse response = httpclient.execute(httpget)) {
                    System.out.println("----------------------------------------");
                    System.out.println("执行请求 " + httpget.getMethod() + " " + httpget.getUri());
                    System.out.println(response.getCode() + " " + response.getReasonPhrase());
                    System.out.println(EntityUtils.toString(response.getEntity()));
                }
            }
        }
    }

}

【结果】

未完待续…

文章来源:https://blog.csdn.net/HIGK_365/article/details/136985075
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