HTTP协议客户端之HttpClient的基本使用

作者: 分布式与微服务 | 来源:发表于2023-03-14 09:15 被阅读0次

HttpClient的基本使用

概述

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。

HttpClient相比JDK自带的URLConnection，增加了易用性和灵活性，使客户端发送Http请求变得更加容易，而且也方便开发测试接口，大大提高开发的效率。

常用HTTP协议客户端包括有：httpclient、restTemplate、okHttp

官网：https://hc.apache.org/index.html

添加依赖

 <dependency>
     <groupId>org.apache.httpcomponents</groupId>
     <artifactId>httpclient</artifactId>
     <version>4.5.13</version>
 </dependency>

Get请求

1.无参数的GET请求

    @Test
    public void get() throws IOException {
        // 创建HttpClient对象
        CloseableHttpClient httpClient = HttpClients.createDefault();
        // 创建HttpGet请求
        HttpGet httpGet = new HttpGet("https://www.baidu.com");
        // 响应对象
        CloseableHttpResponse response = null;
        try {
            // 使用HttpClient发起请求
            response = httpClient.execute(httpGet);
            // 判断响应状态码是否为200
            if (response.getStatusLine().getStatusCode() == 200) {
                // 获取返回数据
                HttpEntity httpEntity = response.getEntity();
                String content = EntityUtils.toString(httpEntity, "UTF-8");
                // 打印数据长度
                log.info("content:{}", content);
            }
        } finally {
            // 释放连接
            if (response != null) {
                response.close();
            }
            httpClient.close();
        }
    }

2.带参数的GET请求

HttpGet httpGet = new HttpGet("https://www.baidu.com/s?wd=java");

POST请求

1.无参数的POST请求

    @Test
    public void post() throws IOException {
        // 创建HttpClient对象
        CloseableHttpClient httpClient = HttpClients.createDefault();
        // 创建HttpGet请求
        HttpPost httpPost = new HttpPost("http://www.baidu.com");
        // 响应对象
        CloseableHttpResponse response = null;
        try {
            // 使用HttpClient发起请求
            response = httpClient.execute(httpPost);
            // 判断响应状态码是否为200
            if (response.getStatusLine().getStatusCode() == 200) {
                // 获取返回数据
                HttpEntity httpEntity = response.getEntity();
                String content = EntityUtils.toString(httpEntity, "UTF-8");
                // 打印数据长度
                log.info("content:{}", content);
            }
        } finally {
            // 释放连接
            if (response != null) {
                response.close();
            }
            httpClient.close();
        }
    }

2.带参数的POST请求

    public static void main(String[] args) throws Exception {
        // 创建HttpClient对象
        CloseableHttpClient httpClient = HttpClients.createDefault();
        // 创建HttpPost对象，设置url访问地址
        HttpPost httpPost = new HttpPost("https://fanyi.baidu.com/langdetect");

        // 声明List集合，封装表单中的参数
        List<NameValuePair> params = new ArrayList<NameValuePair>();
        // 实际请求地址：https://fanyi.baidu.com/langdetect?query=Java
        params.add(new BasicNameValuePair("query", "Java"));

        // 创建表单的Entity对象,第一个参数是封装好的表单数据，第二个参数是编码
        UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(params, "utf8");
        //设置表单的Entity对象到Post请求中
        httpPost.setEntity(formEntity);

        CloseableHttpResponse response = null;
        try {
            // 使用HttpClient发起请求，获取response
            response = httpClient.execute(httpPost);
            // 解析响应
            if (response.getStatusLine().getStatusCode() == 200) {
                String content = EntityUtils.toString(response.getEntity(), "utf8");
                log.info("content={}", content);
            }
        } finally {
            // 关闭资源
            response.close();
            httpClient.close();
        }
    }

连接池

每次请求都要创建HttpClient，会有频繁创建和销毁的问题，可以使用连接池来解决这个问题。

public class HttpClientPool {

    public static PoolingHttpClientConnectionManager getHttpClientPool(){
        // 创建连接池管理器
        PoolingHttpClientConnectionManager poolingHttpClientConnectionManager = new PoolingHttpClientConnectionManager();
        // 设置最大连接数
        poolingHttpClientConnectionManager.setMaxTotal(100);
        // 设置每个主机的最大连接数
        poolingHttpClientConnectionManager.setDefaultMaxPerRoute(10);
        return poolingHttpClientConnectionManager;
    }

    public static void main(String[] args) {
        // 使用连接池管理器发起请求
        PoolingHttpClientConnectionManager httpClientPool = HttpClientPool.getHttpClientPool();
        // 从连接池中获取HttpClient对象
        CloseableHttpClient httpClient = HttpClients.custom().setConnectionManager(httpClientPool).build();
    }
}

请求参数配置

对请求进行参数配置，如cookie设置，代理设置，以及常用的请求超时时间设置。

public class HttpClientPool {

    public static PoolingHttpClientConnectionManager getHttpClientPool() {
        // 创建连接池管理器
        PoolingHttpClientConnectionManager poolingHttpClientConnectionManager = new PoolingHttpClientConnectionManager();
        // 设置最大连接数
        poolingHttpClientConnectionManager.setMaxTotal(100);
        // 设置每个主机的最大连接数
        poolingHttpClientConnectionManager.setDefaultMaxPerRoute(10);
        return poolingHttpClientConnectionManager;
    }

    public static void main(String[] args) throws IOException {
        // 使用连接池管理器发起请求
        PoolingHttpClientConnectionManager httpClientPool = HttpClientPool.getHttpClientPool();
        // 从连接池中获取HttpClient对象
        CloseableHttpClient httpClient = HttpClients.custom().setConnectionManager(httpClientPool).build();

        HttpGet httpGet = new HttpGet("http://www.baidu.com");
        // 配置请求信息
        RequestConfig config = RequestConfig.custom()
                // 创建连接的最长时间，单位是毫秒
                .setConnectTimeout(1000)
                // 设置获取连接的最长时间，单位是毫秒
                .setConnectionRequestTimeout(500)
                // 设置数据传输的最长时间，单位是毫秒
                .setSocketTimeout(10 * 1000)
                .build();
        // 给请求设置请求信息
        httpGet.setConfig(config);

        // 使用HttpClient发起请求，获取response
        CloseableHttpResponse execute = httpClient.execute(httpGet);
    }
}

工具类封装

HttpClientResult

/**
 * Description: 封装httpClient响应结果
 */

@Data
@AllArgsConstructor
@NoArgsConstructor
public class HttpClientResult implements Serializable {

    /**
     * 响应状态码
     */
    private int code;

    /**
     * 响应数据
     */
    private String content;
}

HttpClientUtils

import org.apache.http.HttpStatus;
import org.apache.http.NameValuePair;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.*;
import org.apache.http.client.utils.URIBuilder;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.*;

/**
 * Description: httpClient工具类
 */
public class HttpClientUtils {

    // 编码格式。发送编码格式统一用UTF-8
    private static final String ENCODING = "UTF-8";

    // 设置连接超时时间，单位毫秒。
    private static final int CONNECT_TIMEOUT = 6000;

    // 请求获取数据的超时时间(即响应时间)，单位毫秒。
    private static final int SOCKET_TIMEOUT = 6000;

    /**
     * 发送get请求；不带请求头和请求参数
     *
     * @param url 请求地址
     */
    public static HttpClientResult doGet(String url) throws Exception {
        return doGet(url, null, null);
    }

    /**
     * 发送get请求；带请求参数
     *
     * @param url    请求地址
     * @param params 请求参数集合
     */
    public static HttpClientResult doGet(String url, Map<String, String> params) throws Exception {
        return doGet(url, null, params);
    }

    /**
     * 发送get请求；带请求头和请求参数
     *
     * @param url     请求地址
     * @param headers 请求头集合
     * @param params  请求参数集合
     */
    public static HttpClientResult doGet(String url, Map<String, String> headers, Map<String, String> params) throws Exception {
        // 创建httpClient对象
        CloseableHttpClient httpClient = HttpClients.createDefault();

        // 创建访问的地址
        URIBuilder uriBuilder = new URIBuilder(url);
        if (params != null) {
            Set<Map.Entry<String, String>> entrySet = params.entrySet();
            for (Map.Entry<String, String> entry : entrySet) {
                uriBuilder.setParameter(entry.getKey(), entry.getValue());
            }
        }

        // 创建http对象
        HttpGet httpGet = new HttpGet(uriBuilder.build());
        /**
         * setConnectTimeout：设置连接超时时间，单位毫秒。
         * setConnectionRequestTimeout：设置从connect Manager(连接池)获取Connection
         * 超时时间，单位毫秒。这个属性是新加的属性，因为目前版本是可以共享连接池的。
         * setSocketTimeout：请求获取数据的超时时间(即响应时间)，单位毫秒。 如果访问一个接口，多少时间内无法返回数据，就直接放弃此次调用。
         */
        RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(CONNECT_TIMEOUT).setSocketTimeout(SOCKET_TIMEOUT).build();
        httpGet.setConfig(requestConfig);

        // 设置请求头
        packageHeader(headers, httpGet);

        try {
            // 执行请求并获得响应结果
            return getHttpClientResult(httpClient, httpGet);
        } finally {
            // 释放资源
            close(httpClient);
        }
    }

    /**
     * 发送post请求；不带请求头和请求参数
     *
     * @param url 请求地址
     */
    public static HttpClientResult doPost(String url) throws Exception {
        return doPost(url, null, null);
    }

    /**
     * 发送post请求；带请求参数
     *
     * @param url    请求地址
     * @param params 参数集合
     */
    public static HttpClientResult doPost(String url, Map<String, String> params) throws Exception {
        return doPost(url, null, params);
    }

    /**
     * 发送post请求；带请求头和请求参数
     *
     * @param url     请求地址
     * @param headers 请求头集合
     * @param params  请求参数集合
     */
    public static HttpClientResult doPost(String url, Map<String, String> headers, Map<String, String> params) throws Exception {
        // 创建httpClient对象
        CloseableHttpClient httpClient = HttpClients.createDefault();

        // 创建http对象
        HttpPost httpPost = new HttpPost(url);
        /**
         * setConnectTimeout：设置连接超时时间，单位毫秒。
         * setConnectionRequestTimeout：设置从connect Manager(连接池)获取Connection
         * 超时时间，单位毫秒。这个属性是新加的属性，因为目前版本是可以共享连接池的。
         * setSocketTimeout：请求获取数据的超时时间(即响应时间)，单位毫秒。 如果访问一个接口，多少时间内无法返回数据，就直接放弃此次调用。
         */
        RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(CONNECT_TIMEOUT).setSocketTimeout(SOCKET_TIMEOUT).build();
        httpPost.setConfig(requestConfig);
        // 设置请求头
        /*httpPost.setHeader("Cookie", "");
        httpPost.setHeader("Accept", "application/json");
        httpPost.setHeader("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/105.0.0.0 Safari/537.36");*/
        packageHeader(headers, httpPost);

        // 封装请求参数
        packageParam(params, httpPost);

        try {
            // 执行请求并获得响应结果
            return getHttpClientResult(httpClient, httpPost);
        } finally {
            // 释放资源
            close(httpClient);
        }
    }

    /**
     * 发送put请求；不带请求参数
     *
     * @param url 请求地址
     */
    public static HttpClientResult doPut(String url) throws Exception {
        return doPut(url, null);
    }

    /**
     * 发送put请求；带请求参数
     *
     * @param url    请求地址
     * @param params 参数集合
     */
    public static HttpClientResult doPut(String url, Map<String, String> params) throws Exception {
        CloseableHttpClient httpClient = HttpClients.createDefault();
        HttpPut httpPut = new HttpPut(url);
        RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(CONNECT_TIMEOUT).setSocketTimeout(SOCKET_TIMEOUT).build();
        httpPut.setConfig(requestConfig);

        packageParam(params, httpPut);

        try {
            return getHttpClientResult(httpClient, httpPut);
        } finally {
            close(httpClient);
        }
    }

    /**
     * 发送delete请求；不带请求参数
     *
     * @param url 请求地址
     */
    public static HttpClientResult doDelete(String url) throws Exception {
        CloseableHttpClient httpClient = HttpClients.createDefault();
        HttpDelete httpDelete = new HttpDelete(url);
        RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(CONNECT_TIMEOUT).setSocketTimeout(SOCKET_TIMEOUT).build();
        httpDelete.setConfig(requestConfig);

        try {
            return getHttpClientResult(httpClient, httpDelete);
        } finally {
            close(httpClient);
        }
    }

    /**
     * 发送delete请求；带请求参数
     *
     * @param url    请求地址
     * @param params 参数集合
     */
    public static HttpClientResult doDelete(String url, Map<String, String> params) throws Exception {
        if (params == null) {
            params = new HashMap<>();
        }

        params.put("_method", "delete");
        return doPost(url, params);
    }

    /**
     * Description: 封装请求头
     */
    public static void packageHeader(Map<String, String> params, HttpRequestBase httpMethod) {
        // 封装请求头
        if (params != null) {
            Set<Map.Entry<String, String>> entrySet = params.entrySet();
            for (Map.Entry<String, String> entry : entrySet) {
                // 设置到请求头到HttpRequestBase对象中
                httpMethod.setHeader(entry.getKey(), entry.getValue());
            }
        }
    }

    /**
     * Description: 封装请求参数
     */
    public static void packageParam(Map<String, String> params, HttpEntityEnclosingRequestBase httpMethod)
            throws UnsupportedEncodingException {
        // 封装请求参数
        if (params != null) {
            List<NameValuePair> nvps = new ArrayList<>();
            Set<Map.Entry<String, String>> entrySet = params.entrySet();
            for (Map.Entry<String, String> entry : entrySet) {
                nvps.add(new BasicNameValuePair(entry.getKey(), entry.getValue()));
            }

            // 设置到请求的http对象中
            httpMethod.setEntity(new UrlEncodedFormEntity(nvps, ENCODING));
        }
    }

    /**
     * Description: 获得响应结果
     */
    public static HttpClientResult getHttpClientResult(CloseableHttpClient httpClient, HttpRequestBase httpMethod) throws IOException {
        try (CloseableHttpResponse httpResponse = httpClient.execute(httpMethod)) {
            // 获取返回结果
            if (httpResponse != null && httpResponse.getStatusLine() != null) {
                String content = "";
                if (httpResponse.getEntity() != null) {
                    content = EntityUtils.toString(httpResponse.getEntity(), ENCODING);
                }
                return new HttpClientResult(httpResponse.getStatusLine().getStatusCode(), content);
            }
        }
        return new HttpClientResult(HttpStatus.SC_INTERNAL_SERVER_ERROR, null);
    }

    /**
     * Description: 释放资源
     */
    public static void close(CloseableHttpClient httpClient) throws IOException {
        if (httpClient != null) {
            httpClient.close();
        }
    }

}

测试

public class HttpClientUtilsTest {

    /**
     * Description: 测试get无参请求
     */
    @Test
    public void testGet() throws Exception {
        HttpClientResult result = HttpClientUtils.doGet("https://www.baidu.com");
        System.out.println(result);
    }

    /**
     * Description: 测试get带参请求
     */
    @Test
    public void testGetWithParam() throws Exception {
        Map<String, String> params = new HashMap<String, String>();
        params.put("word", "java");
        HttpClientResult result = HttpClientUtils.doGet("url", params);
        System.out.println(result);
    }

    /**
     * Description: 测试post带请求头不带请求参数
     */
    @Test
    public void testPost() throws Exception {
        Map<String, String> headers = new HashMap<String, String>();
        headers.put("Cookie", "cokie");
        headers.put("Accept", "application/json");
        headers.put("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/105.0.0.0 Safari/537.36");
        HttpClientResult result = HttpClientUtils.doPost("url", headers, null);
        System.out.println(result);
    }

    /**
     * Description: 测试post带参请求
     */
    @Test
    public void testPostWithParam() throws Exception {
        Map<String, String> params = new HashMap<String, String>();
        params.put("word", "java");
        HttpClientResult result = HttpClientUtils.doPost("url", params);
        System.out.println(result);
    }
}

HTTP协议客户端之HttpClient的基本使用

HttpClient的基本使用

概述

添加依赖

Get请求

POST请求

连接池

请求参数配置

工具类封装

HttpClientResult

HttpClientUtils

测试

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