1. 引入 maven 依赖

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

2. 发送 GET 方式的请求

package com.zxe;

import org.apache.http.HttpEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
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;

@SpringBootTest
public class HttpClient {

    @Test
    public void test() throws Exception {

        //1.创建httpclient对象
        CloseableHttpClient httpClient = HttpClients.createDefault();
        //2.创建请求对象
        HttpGet httpGet = new HttpGet("http://localhost:8080/user/status");
        //3.发送请求，接收响应结果
        CloseableHttpResponse response = httpClient.execute(httpGet);

        //4.获取服务端返回的状态码
        int statusCode = response.getStatusLine().getStatusCode();
        System.out.println("服务端返回的状态码为：" + statusCode);
        //5.解析响应体
        HttpEntity entity = response.getEntity();
        String body = EntityUtils.toString(entity);
        System.out.println("服务端返回的数据为：" + body);

        //6.关闭资源
        response.close();
        httpClient.close();

    }

}

3. 发送 POST 方式的请求

package com.zxe;

import org.apache.http.HttpEntity;
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.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;
import org.json.JSONObject;
import org.junit.jupiter.api.Test;
import org.springframework.boot.test.context.SpringBootTest;

@SpringBootTest
public class HttpClient {

    @Test
    public void test() throws Exception {

        //1.创建httpclient对象
        CloseableHttpClient httpClient = HttpClients.createDefault();
        //2.创建请求对象
        HttpPost httpPost = new HttpPost("http://localhost:8080/admin/employee/login");
        //3.设置请求体参数
        JSONObject jsonObject = new JSONObject();
        jsonObject.put("username", "admin");
        jsonObject.put("password", "123456");
        StringEntity entity = new StringEntity(jsonObject.toString());
        entity.setContentEncoding("utf-8");
        //4.数据格式
        entity.setContentType("application/json");
        httpPost.setEntity(entity);
        //5.发送请求，接收响应结果
        CloseableHttpResponse response = httpClient.execute(httpPost);

        //4.获取服务端返回的状态码
        int statusCode = response.getStatusLine().getStatusCode();
        System.out.println("服务端返回的状态码为：" + statusCode);
        //5.解析响应体
        HttpEntity entity1 = response.getEntity();
        String body = EntityUtils.toString(entity1);
        System.out.println("服务端返回的数据为：" + body);

        //6.关闭资源
        response.close();
        httpClient.close();

    }

}