Java實現HttpClient發送GET、POST請求(https、http)

1、引入相關依賴包

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

2、主要類HttpClientsHelper

package com.ruoyi.common.utils.http;

import org.apache.http.HttpEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpPost;
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.BasicHeader;
import org.apache.http.util.EntityUtils;

import java.io.IOException;

/**
 * 作者：葉長種
 * 創建日期：2021/11/20 15:29
 * 描述：HttpClients輔助類
 */
public class HttpClientsHelper {

    /**
     * 向指定 URL 發送POST方法的請求
     * @param url 發送請求的 URL
     * @param jsonString 請求參數，請求參數應該是json字符串的形式。
     * @return 所代表遠程資源的響應結果，對應的也是json字符串
     */
    public static String sendPost(String url, String jsonString){
        String body = "";
        try {
            //創建httpclient對象
            CloseableHttpClient client = HttpClients.createDefault();
            //創建post方式請求對象
            HttpPost httpPost = new HttpPost(url);

            //裝填參數
            StringEntity s = new StringEntity(jsonString, "utf-8");
            s.setContentEncoding(new BasicHeader("contentType",
                    "application/json"));
            //設置參數到請求對象中
            httpPost.setEntity(s);
            //System.out.println("請求地址：" + url);

            //設置header信息
            //指定報文頭【Content-type】、【User-Agent】
            //httpPost.setHeader("Content-type", "application/x-www-form-urlencoded");
            httpPost.setHeader("Content-type", "application/json");
            httpPost.setHeader("User-Agent", "Mozilla/4.0 (compatible; MSIE 5.0; Windows NT; DigExt)");

            //執行請求操作，並拿到結果（同步阻塞）
            CloseableHttpResponse response = client.execute(httpPost);
            //獲取結果實體
            HttpEntity entity = response.getEntity();
            if (entity != null) {
                //按指定編碼轉換結果實體為String類型
                body = EntityUtils.toString(entity, "UTF-8");
            }
            EntityUtils.consume(entity);
            //釋放鏈接
            response.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return body;
    }
}