介绍

HTTP客户端是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。

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

核心AP1:

• 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

入门案例

导入坐标

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

创建测试类 HttpClientTest

@SpringBootTest
public class HttpClientTest {
        
}

创建测试通过httpclient发送GET请求

• // 1.创建HttpClient对象
CloseableHttpClient httpClient = HttpClients.createDefault();
• // 2.创建HttpGet对象，设置请求地址
HttpGet httpGet = new HttpGet("http://localhost:8080/user/shop/status");
• // 3.使用HttpClient对象发送请求，并获取响应
CloseableHttpResponse response = httpClient.execute(httpGet);
• // 4.打印响应状态码
System.out.println("状态码为：" + response.getStatusLine().getStatusCode());
HttpEntity entity = response.getEntity();
String boby = EntityUtils.toString(entity);
// 打印响应内容
System.out.println("响应内容为：" + boby);
• // 最后关闭HttpClient和HttpResponse对象
response.close();
httpClient.close();

完整代码

/**
     * 测试通过httpclient发送GET请求
     */
    @Test
    public void testGet() throws Exception {
        // 创建HttpClient对象
        CloseableHttpClient httpClient = HttpClients.createDefault();

        // 创建HttpGet对象，设置请求地址
        HttpGet httpGet = new HttpGet("http://localhost:8080/user/shop/status");
        // 使用HttpClient对象发送请求，并获取响应
        CloseableHttpResponse response = httpClient.execute(httpGet);
        // 打印响应状态码
        System.out.println("状态码为：" + response.getStatusLine().getStatusCode());
        HttpEntity entity = response.getEntity();
        String boby = EntityUtils.toString(entity);
        // 打印响应内容
        System.out.println("响应内容为：" + boby);

        // 关闭HttpClient和HttpResponse对象
        response.close();
        httpClient.close();
    }

运行测试结果

前提项目已经启动

创建测试通过httpclient发送POST请求

• // 1.创建HttpClient对象
CloseableHttpClient httpClient = HttpClients.createDefault();
• // 2.创建HttpPost对象，设置请求地址和请求参数
HttpPost httpPOST = new HttpPost("http://localhost:8080/admin/employee/login");
• // 3.设置请求参数JSON
JSONObject json = new JSONObject();
json.put("username", "admin");
json.put("password", "123456");
StringEntity entity = new StringEntity(json.toString());
• //4.指定请求内容类型为json
entity.setContentType("application/json");
• //5.指定请求参数编码格式
entity.setContentEncoding("UTF-8");
• //6.设置请求参数
httpPOST.setEntity(entity);
• // 7.使用HttpClient对象发送请求，并获取响应
CloseableHttpResponse response = httpClient.execute(httpPOST);
• // 8.打印响应状态码
System.out.println("状态码为：" + response.getStatusLine().getStatusCode());
HttpEntity responseEntity = response.getEntity();
String responseBody = EntityUtils.toString(responseEntity);
• // 9.打印响应内容
System.out.println("响应内容为：" + responseBody);
• // 10.关闭HttpClient和HttpResponse对象
response.close();
httpClient.close();

完整代码

/**
 * 测试通过httpclient发送POST请求
 */
@Test
public void testPOST() throws Exception {
    // 1.创建HttpClient对象
    CloseableHttpClient httpClient = HttpClients.createDefault();
    // 2.创建HttpPost对象，设置请求地址和请求参数
    HttpPost httpPOST = new HttpPost("http://localhost:8080/admin/employee/login");
    // 3.设置请求参数
    JSONObject json = new JSONObject();
    json.put("username", "admin");
    json.put("password", "123456");
    StringEntity entity = new StringEntity(json.toString());
    //4.指定请求内容类型为json
    entity.setContentType("application/json");
    //5.指定请求参数编码格式
    entity.setContentEncoding("UTF-8");
    //6.设置请求参数
    httpPOST.setEntity(entity);
    // 7.使用HttpClient对象发送请求，并获取响应
    CloseableHttpResponse response = httpClient.execute(httpPOST);
    // 8.打印响应状态码
    System.out.println("状态码为：" + response.getStatusLine().getStatusCode());
    HttpEntity responseEntity = response.getEntity();
    String responseBody = EntityUtils.toString(responseEntity);
    // 9.打印响应内容
    System.out.println("响应内容为：" + responseBody);
    // 10.关闭HttpClient和HttpResponse对象
    response.close();
    httpClient.close();

}

运行测试结果

前提项目已经启动