HTTP請求(HttpClient和PostMan)

在沒有頁面的情況下來獲取接口返回的數據(一般都是為JSON),我們可以通過一些工具模擬HTTP請求

服務端模擬HTTP請求

通過JAVA代碼進行HTTP請求的發送

1.准備依賴

    <!-- https://mvnrepository.com/artifact/org.apache.httpcomponents/httpclient -->
    <dependency>
      <groupId>org.apache.httpcomponents</groupId>
      <artifactId>httpclient</artifactId>
      <version>4.5.6</version>
    </dependency>

2.創建post和get方式請求的方法

package com.ty.http;


import org.apache.http.HttpEntity;
import org.apache.http.NameValuePair;
import org.apache.http.client.entity.UrlEncodedFormEntity;
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.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;
import java.util.List;

public class MyHttpClient {
    private static void myPost() throws IOException {
        //建立連接請求
        CloseableHttpClient httpClient = HttpClients.createDefault();
        //創建post請求
        HttpPost httpPost = new HttpPost("http://eureka7002.com:6061/myServlet");
        //創建參數隊列
        List<NameValuePair> nameValuePairList=new ArrayList<>();
        //准備請求參數隊列
        nameValuePairList.add(new BasicNameValuePair("userName","天雁"));
        //
        UrlEncodedFormEntity urlEncodedFormEntity=new UrlEncodedFormEntity(nameValuePairList,"UTF-8");
        //講實體封裝到請求當中
        httpPost.setEntity(urlEncodedFormEntity);
        //發送請求
        CloseableHttpResponse response = httpClient.execute(httpPost);
        HttpEntity entity = response.getEntity();
        if (entity!=null){
            System.out.println("接收到的響應信息:--------"+EntityUtils.toString(entity,"UTF-8"));
        }
        //資源釋放
        response.close();
        httpClient.close();

    }

    private static void myGet() throws IOException {

        //建立連接請求
        CloseableHttpClient httpClient = HttpClients.createDefault();
        //創建get請求
        HttpGet get=new HttpGet("https://www.baidu.com/");
        CloseableHttpResponse response = httpClient.execute(get);
        int statusCode = response.getStatusLine().getStatusCode();
        //響應成功在操作
        if (statusCode==200) {
            //獲取響應實體
            HttpEntity entity = response.getEntity();

            //打印響應內容長度
            System.out.println("響應文本長度:"+entity.getContentLength());
            //打印響應內容
            System.out.println("響應內容如下:\n"+EntityUtils.toString(entity,"UTF-8"));
        }
        System.out.println("--------------------------響應內容打印完畢");
        //釋放資源
        response.close();
        httpClient.close();
    }

    public static void main(String[] args) {
        try {
          //  myGet();
            myPost();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

4.get測試百度返回結果

 

 5.post測試本機的另一個服務

5.1給項目准備依賴

    <!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>3.1.0</version>
      <scope>provided</scope>
    </dependency>
    <dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>fastjson</artifactId>
      <version>1.2.58</version>
    </dependency>

5.2創建一個Servlet,接收一個參數,返回json串

package com.ty.servlet;

import com.alibaba.fastjson.JSON;

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("/myServlet")
public class MyServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    doPost(req,resp);
    }
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("UTF-8");
        String userName = req.getParameter("userName");
        resp.setHeader("Content-type", "text/html;charset=UTF-8");
        System.out.println("接受到的數據:"+userName);
        String json="成功響應";
        resp.getWriter().write(JSON.toJSONString(json));
    }
}

5.3啟動服務,發送post請求,結果如下

 

 

 

 

客戶端工具模擬HTTP請求

PostMan發送get請求百度

 

 發送post請求