HttpClient GET/POST

1、Maven项目依赖

<!-- httpclient -->
<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.5.10</version>
</dependency>

2、下面有三个案列

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
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.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.StringEntity;
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.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Objects;

/**
 * @Description: httpclient帮助类
 * @Date : 2019/12/30 17:26
 */
public class HttpClientUtils {


    /**
     * @Description: httpclient Post
     * @Date : 2019/12/30 18:11
     */
    public static String httpClientPost(String url, Map<String, Object> map) {
        // 返回值
        String result = "";

        // 通过HttpPost来发送post请求
        HttpPost httpPost = new HttpPost(url);

        // 响应
        CloseableHttpResponse response;

        // 获取默认的请求客户端
        try (CloseableHttpClient client = HttpClients.createDefault()) {
            // 第三步：构造list集合参数
            List<NameValuePair> list = new ArrayList<>();

            for (String m : map.keySet()) {
                BasicNameValuePair basicNameValuePair =
                        new BasicNameValuePair(m, map.get(m).toString());
                list.add(basicNameValuePair);
            }

            // 第二步：我们发现Entity是一个接口，所以只能找实现类，发现实现类又需要一个集合，集合的泛型是NameValuePair类型
            UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(list);
            // 第一步：通过setEntity 将我们的entity对象传递过去
            httpPost.setEntity(formEntity);

            // 是一个中间的桥梁，在httpClient里面，是连接我们的请求与响应的一个中间桥梁，所有的请求参数都是通过HttpEntity携带过去的
            // 通过client来执行请求，获取一个响应结果
            response = client.execute(httpPost);
            HttpEntity entity = response.getEntity();
            result = EntityUtils.toString(entity, "UTF-8");
        } catch (Exception e) {
            e.printStackTrace();
        }
        return result;
    }

    /**
     * @Description: httpclient post 封装
     * @RequestType: application/json
     * @Date : 2019/12/30 17:08
     */
    public static String httpClientPost(String url, String jsonParams) {
        // 返回值
        String result = "";

        // 定义请求方式
        HttpPost httpPost = new HttpPost(url);

        // 设置请求配置
        RequestConfig requestConfig = RequestConfig.custom().
                setConnectTimeout(180 * 1000).setConnectionRequestTimeout(180 * 1000)
                .setSocketTimeout(180 * 1000).setRedirectsEnabled(true).build();
        httpPost.setConfig(requestConfig);

        // 设置请求类型
        httpPost.setHeader("Content-Type", "application/json");

        // 创建httpclient客户端
        try (CloseableHttpClient httpClient = HttpClients.createDefault()) {

            httpPost.setEntity(new StringEntity(jsonParams, ContentType.create("application/json", "utf-8")));
            HttpResponse response = httpClient.execute(httpPost);
            if (response != null && response.getStatusLine().getStatusCode() == 200) {
                result = EntityUtils.toString(response.getEntity());
            }

        } catch (Exception e) {
            e.printStackTrace();
        }
        return result;
    }

    /**
     * @Description: httpclient get封装
     * @Date : 2019/12/30 17:12
     */
    public static String httpClientGet(String url, Map<String, Object> map) {
        // 参数
        String params = "";

        StringBuffer sb = new StringBuffer();
        // 准备拼接参数
        if (Objects.nonNull(map)) {
            params = url + "?";
            for (Object m : map.keySet()) {
                sb = sb.append("&").append(m).append(map.get(m));
            }
            params += sb.substring(1, sb.length());
        }

        // 接受返回值
        String result = "";

        // 创建http客户端
        try (CloseableHttpClient client = HttpClients.createDefault()) {
            // 采用get请求
            HttpGet httpGet = new HttpGet(params);
            // 通过client调用execute方法，得到我们的执行结果就是一个response，所有的数据都封装在response里面了
            CloseableHttpResponse Response = client.execute(httpGet);
            // HttpEntity
            // 是一个中间的桥梁，在httpClient里面，是连接我们的请求与响应的一个中间桥梁，所有的请求参数都是通过HttpEntity携带过去的
            // 所有的响应的数据，也全部都是封装在HttpEntity里面
            HttpEntity entity = Response.getEntity();
            // 通过EntityUtils 来将我们的数据转换成字符串
            result = EntityUtils.toString(entity, "UTF-8");
        } catch (Exception e) {
            e.printStackTrace();
        }
        return result;
    }

}