HTTP协议客户端之HttpClient的基本使用

心已赠人 2023-09-27 15:59 127阅读 0赞

## HttpClient的基本使用 ##

### 概述 ###

> HttpClient 是Apache Jakarta Common 下的子项目，可以用来提供高效的、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相比JDK自带的URLConnection，增加了易用性和灵活性，使客户端发送Http请求变得更加容易，而且也方便开发测试接口，大大提高开发的效率。

> 常用HTTP协议客户端包括有：httpclient、restTemplate、okHttp

官网：`https://hc.apache.org/index.html`

![5f3d7d6a953121b7046755801fb9e2c8.png][]

### 添加依赖 ###

<dependency>
         <groupId>org.apache.httpcomponents</groupId>
         <artifactId>httpclient</artifactId>
         <version>4.5.13</version>
     </dependency>

### Get请求 ###

**1.无参数的GET请求**

@Test
        public void get() throws IOException {
            // 创建HttpClient对象
            CloseableHttpClient httpClient = HttpClients.createDefault();
            // 创建HttpGet请求
            HttpGet httpGet = new HttpGet("https://www.baidu.com");
            // 响应对象
            CloseableHttpResponse response = null;
            try {
                // 使用HttpClient发起请求
                response = httpClient.execute(httpGet);
                // 判断响应状态码是否为200
                if (response.getStatusLine().getStatusCode() == 200) {
                    // 获取返回数据
                    HttpEntity httpEntity = response.getEntity();
                    String content = EntityUtils.toString(httpEntity, "UTF-8");
                    // 打印数据长度
                    log.info("content:{}", content);
                }
            } finally {
                // 释放连接
                if (response != null) {
                    response.close();
                }
                httpClient.close();
            }
        }

**2.带参数的GET请求**

HttpGet httpGet = new HttpGet("https://www.baidu.com/s?wd=java");

### POST请求 ###

**1.无参数的POST请求**

@Test
        public void post() throws IOException {
            // 创建HttpClient对象
            CloseableHttpClient httpClient = HttpClients.createDefault();
            // 创建HttpGet请求
            HttpPost httpPost = new HttpPost("http://www.baidu.com");
            // 响应对象
            CloseableHttpResponse response = null;
            try {
                // 使用HttpClient发起请求
                response = httpClient.execute(httpPost);
                // 判断响应状态码是否为200
                if (response.getStatusLine().getStatusCode() == 200) {
                    // 获取返回数据
                    HttpEntity httpEntity = response.getEntity();
                    String content = EntityUtils.toString(httpEntity, "UTF-8");
                    // 打印数据长度
                    log.info("content:{}", content);
                }
            } finally {
                // 释放连接
                if (response != null) {
                    response.close();
                }
                httpClient.close();
            }
        }

**2.带参数的POST请求**

public static void main(String[] args) throws Exception {
            // 创建HttpClient对象
            CloseableHttpClient httpClient = HttpClients.createDefault();
            // 创建HttpPost对象，设置url访问地址
            HttpPost httpPost = new HttpPost("https://fanyi.baidu.com/langdetect");
    
            // 声明List集合，封装表单中的参数
            List<NameValuePair> params = new ArrayList<NameValuePair>();
            // 实际请求地址：https://fanyi.baidu.com/langdetect?query=Jav

[5f3d7d6a953121b7046755801fb9e2c8.png]: https://img-blog.csdnimg.cn/img_convert/5f3d7d6a953121b7046755801fb9e2c8.png