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1. HttpClient 介绍

HttpClient 是 Apache Jakarta Common下的子项目，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 已经应用在很多的项目中，比如 Apache Jakarta上很著名的另外两个开源项目 Cactus 和HTMLUnit 都使用了 HttpClient。

核心 API：

• HttpClient
• HttpClients
• CloseableHttpClient
• HttpGet
• HttpPost

发送请求步骤：

• 创建 HttpClient 对象
• 创建 Http 请求对象
• 调用 HttpClient 的 execute 方法发送请求

2. 导入坐标

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

3. 使用 HttpClient 发送 Get 请求

package com.sky.test;import org.apache.http.HttpEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;
import org.junit.jupiter.api.Test;
import org.springframework.boot.test.context.SpringBootTest;import java.io.IOException;@SpringBootTest
public class HttpClientTest {/*** 测试httpclient GET*/@Testpublic void testGet() throws IOException {// 创建httpclient对象CloseableHttpClient httpClient = HttpClients.createDefault();// 创建请求对象HttpGet httpGet = new HttpGet("http://localhost:8080/user/shop/status");// 发送请求，接收响应CloseableHttpResponse response = httpClient.execute(httpGet);// 获取状态码int statusCode = response.getStatusLine().getStatusCode();System.out.println("获取服务器返回的状态码" + statusCode);// 获取响应数据HttpEntity entity = response.getEntity();String body = EntityUtils.toString(entity);System.out.println("响应数据" + body);// 关闭资源response.close();httpClient.close();}
}

4. 使用 HttpClient 发送 Post 请求

package com.sky.test;import com.alibaba.fastjson.JSONObject;
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.util.EntityUtils;
import org.junit.jupiter.api.Test;
import org.springframework.boot.test.context.SpringBootTest;import java.io.IOException;@SpringBootTest
public class HttpClientTest {/*** 测试httpclient POST*/@Testpublic void testPost() throws IOException {// 创建httpclient对象CloseableHttpClient httpClient = HttpClients.createDefault();// 创建请求对象HttpPost httpPost = new HttpPost("http://localhost:8080/admin/employee/login");// 封装post请求JSONObject jsonObject = new JSONObject();jsonObject.put("username", "admin");jsonObject.put("password", "123456");StringEntity entity = new StringEntity(jsonObject.toString());// 指定请求编码方式entity.setContentEncoding("utf-8");// 数据格式entity.setContentType("application/json");httpPost.setEntity(entity);// 发送请求，接收响应CloseableHttpResponse response = httpClient.execute(httpPost);// 获取状态码int statusCode = response.getStatusLine().getStatusCode();System.out.println("响应码为: " + statusCode);// 获取响应数据HttpEntity entity1 = response.getEntity();String body = EntityUtils.toString(entity1);System.out.println("响应数据" + body);// 关闭资源response.close();httpClient.close();}}