SpringBoot中HttpClient的使用

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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.httpcomponentsgroupId>
    <artifactId>httpclientartifactId>
dependency>
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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
     */
    @Test
    public 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();
    }
}
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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
     */
    @Test
    public 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();
    }

}
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