HttpClient POST/GET方法

前言：

網絡API接口：https://api.apiopen.top/searchMusic

此API接口返回類型為JSON格式類型

GET：從指定資源請求數據

POST：向指定資源提交要被處理的數據

GET與POST的區別：

①GET在瀏覽器回退時是無害的，而POST會再次提交請求。

②GET只支持URL編碼。

③GET參數通過URL傳遞，參數直接暴露在URL中會泄露信息，POST通過Request body傳遞不會有這樣的問題。

④GET請求在URL中傳遞參數有長度限制，POST沒有長度限制。

⑤對POST請求會險發送Header，服務器相應成功，在發送Date，服務器再次響應，需響應兩次。GET會把Header與Date一起發送到服務端，服務器只響應一次。

一、POST方法

創建POST方法類

package com.HttpClient.Test;

import java.io.IOException;
import java.util.ArrayList;

import org.apache.http.HttpEntity;
import org.apache.http.HttpHost;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.config.RequestConfig;
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.HttpClientBuilder;
import org.apache.http.util.EntityUtils;

import com.HttpClient.jiexi.HttpClient_jiexi;

public class HttpClient_post {
    
    private String entityStr;
    HttpClient_jiexi JSONTOOL = new HttpClient_jiexi();
    
    //封裝POST方法
    public String post(String POST_URL,ArrayList<NameValuePair> list) {
        
        try {
            //把參數放入請求體中
            UrlEncodedFormEntity entityParam = new UrlEncodedFormEntity(list, "UTF-8");
            CloseableHttpClient httpClient = HttpClientBuilder.create().build();
            HttpPost httpPost = new HttpPost(POST_URL);
            httpPost.setEntity(entityParam);
            //發起請求
            CloseableHttpResponse response = httpClient.execute(httpPost);
            //獲取返回狀態，並判斷是否連接成功。
            if (response.getStatusLine().getStatusCode()==200) {
                System.out.println("連接成功");
            } else {
                System.out.println("連接異常");
            }
            // 獲得響應的實體對象
            HttpEntity entity = response.getEntity();
            
            //轉換成字符串
            entityStr = EntityUtils.toString(entity, "UTF-8");
            //關閉請求
            httpClient.close();
            
        } catch (ClientProtocolException e) {
            System.err.println("Http協議異常");
            e.printStackTrace();
        } catch (IOException e) {
            System.err.println("IO異常");
            e.printStackTrace();
        }
        return entityStr;
    }

}

調用POST方法類

package com.HttpClient.Test;

import java.util.ArrayList;
import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONException;
import org.testng.annotations.Test;

public class HttpClient_case1 {
    
    HttpClient_post post = new HttpClient_post();
    private String POST_URL = "https://api.apiopen.top/searchMusic";
    private String entity;
    private ArrayList<NameValuePair> list;
    
    @Test
    public void test1() {   
            // 構造list集合，並添加參數
            BasicNameValuePair basicNameValuePair = new BasicNameValuePair("name", "十年");
            list = new ArrayList<>();
            list.add(basicNameValuePair);
            // 執行請求,需要傳入URL與參數
            entity = post.post(POST_URL,list);
            System.out.println(entity);
    }

}

二、GET方法

創建GET方法類

package com.HttpClient.Test;

import java.io.IOException;
import java.net.URISyntaxException;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;

import org.apache.http.HttpEntity;
import org.apache.http.HttpHost;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.config.RequestConfig;
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.client.utils.URIBuilder;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;

public class HttpClient_get {
    
    public String entityStr ;
    public CloseableHttpResponse response ;

    
    public String get(String GET_URL,ArrayList<NameValuePair> list) throws URISyntaxException{try {
            CloseableHttpClient httpClient = HttpClients.createDefault();
            URIBuilder uriBuilder = new URIBuilder(GET_URL);
            uriBuilder.setParameters(list);
            //根據帶參數的URI對象構建GET請求對象
            HttpGet httpGet = new HttpGet(uriBuilder.build());
            //執行請求
            response = httpClient.execute(httpGet);
            //獲得響應的實體對象
            HttpEntity entity = response.getEntity();
            //轉換成字符串
            entityStr = EntityUtils.toString(entity, "UTF-8");

            //關閉請求
            httpClient.close();
        } catch (ClientProtocolException e) {
            System.err.println("Http協議異常");
            e.printStackTrace();
        } catch (IOException e) {
            System.err.println("IO異常");
            e.printStackTrace();
        }
        return entityStr;
        
    }

}

調用GET方法類

package com.HttpClient.Test;

import java.net.URISyntaxException;
import java.util.ArrayList;
import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONException;
import org.testng.annotations.Test;

public class HttpClient_case1 {
    
    HttpClient_get get = new HttpClient_get();
    private String URL = "https://api.apiopen.top/searchMusic";
    private String entity;
    private ArrayList<NameValuePair> list;
    
    @Test
    public void test1() throws URISyntaxException {   
            // 構造list集合
            BasicNameValuePair basicNameValuePair = new BasicNameValuePair("name", "十年");
            list = new ArrayList<>();
            list.add(basicNameValuePair);
            // 執行請求,需要傳入URL與參數
            entity = get.get(URL, list);
            System.out.println(entity);
            
    }

}