模拟客户端请求 Httpclients—— GET/POST

系统管理员 2022-10-26 03:51 207阅读 0赞

# 一、get，这里请求的是百度官网 #

import org.apache.http.HttpEntity;
    import org.apache.http.client.ClientProtocolException;
    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 java.io.IOException;
    
    public class HttpClientUtils2 {
    
        public static void main(String[] args) throws ClientProtocolException, IOException {
            get("https://www.baidu.com/?tn=49055317_11_hao_pg");
        }
    
        public static void get(String URL) throws IOException {
            //创建一个默认链接
            CloseableHttpClient httpClient = HttpClients.createDefault();
    
            HttpGet httpGet = new HttpGet(URL);
    
           CloseableHttpResponse response = httpClient.execute(httpGet);
           //获取状态码
           int statusCode = response.getStatusLine().getStatusCode();
           if(statusCode == 200){
                HttpEntity entity = response.getEntity();
                String result = EntityUtils.toString(entity,"UTF-8");
               System.out.println("result:"+result);
           }
        }
    }

## 请求结果,返回了百度页面的脚本 ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1N1bl9vZl9SYWlueQ_size_16_color_FFFFFF_t_70][]

# 二、post ,这里请求的是本地的一个简单服务 #

## web服务如下： ##

import javax.servlet.ServletException;
    import javax.servlet.annotation.WebServlet;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.io.IOException;
    
    @WebServlet("/formServlet2")
    public class UserFormServlet extends HttpServlet {
        @Override
        protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
            String username= req.getParameter("username");
            String password = req.getParameter("password");
            String token = req.getHeader("token");
            System.out.println("username"+username );
            System.out.println("password"+password );
            System.out.println("token"+token);
            resp.getWriter().println(username +"---"+password + "---"+token);
        }
    }

## 模拟请求： ##

import org.apache.http.HttpEntity;
    import org.apache.http.NameValuePair;
    import org.apache.http.client.ClientProtocolException;
    import org.apache.http.client.entity.UrlEncodedFormEntity;
    import org.apache.http.client.methods.CloseableHttpResponse;
    import org.apache.http.client.methods.HttpPost;
    import org.apache.http.impl.client.CloseableHttpClient;
    import org.apache.http.impl.client.HttpClients;
    import org.apache.http.message.BasicNameValuePair;
    import org.apache.http.util.EntityUtils;
    
    import java.io.IOException;
    import java.util.ArrayList;
    
    public class HttpClientUtils {
    
        public static void main(String[] args) throws ClientProtocolException, IOException {
            post("http://localhost:8080/formServlet2");
        }
    
        public static void post(String URL) throws IOException {
            //创建一个默认链接
            CloseableHttpClient httpClient = HttpClients.createDefault();
            HttpPost httpPost = new HttpPost(URL);
            httpPost.setHeader("token","my123");
            ArrayList<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
            nameValuePairs.add(new BasicNameValuePair("username","123456"));
            nameValuePairs.add(new BasicNameValuePair("password","000000"));
            UrlEncodedFormEntity urlEncodedFormEntity = new UrlEncodedFormEntity(nameValuePairs,"UTF-8");
            httpPost.setEntity(urlEncodedFormEntity);
            CloseableHttpResponse response = httpClient.execute(httpPost);
            //获取状态码
            int statusCode = response.getStatusLine().getStatusCode();
            if(statusCode == 200){
                HttpEntity entity = response.getEntity();
                String result = EntityUtils.toString(entity, "UTF-8");
                System.out.println(result);
            }
    
        }
    }

## 请求结果 ##

![2021020118131114.png][]

# 说明：该例可模拟访问api，我们开发时经常用postman去模拟请求，测试api #

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1N1bl9vZl9SYWlueQ_size_16_color_FFFFFF_t_70]: /images/20221024/9c646dea79c74897a9c1a20730e1bf97.png
[2021020118131114.png]: /images/20221024/aaae56ea129e4bd3befc4704ec2ba64c.png