參考資料：https://blog.csdn.net/wrongyao/article/details/80250418

1.獲取access_token

public static String getAccessToken(String appId,String appAecret) {
        String url = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid="+appId+"&secret="+appAecret;
        Object result = HttpContenUtil.getURLGetContent(url);
        @SuppressWarnings("unchecked")
        Map<String, Object> openid  = (Map<String, Object>) JSONObject.parse(result.toString());
        
        return ObjectUtil.isEmpty(openid)?null:openid.containsKey("access_token")?openid.get("access_token").toString():null;
    }

2.獲取ticket

3.獲取二維碼

工具類

package com.ry.finance.util;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.nio.charset.StandardCharsets;
import java.security.KeyStore;

import javax.net.ssl.SSLContext;

import com.ry.finance.util.WXUtile.WXUtil;

import org.apache.http.HttpEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.conn.ssl.SSLConnectionSocketFactory;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.message.BasicHeader;
import org.apache.http.protocol.HTTP;
import org.apache.http.ssl.SSLContexts;
import org.apache.http.util.EntityUtils;
import org.springframework.util.ResourceUtils;
import org.springframework.web.multipart.MultipartFile;

public class HttpContenUtil {
    /**
     * get方法訪問
     *
     * @param urlStr
     * @return程序中訪問http數(shù)據(jù)接口
     */
    public static Object getURLGetContent(String urlStr) {
        /** 網(wǎng)絡(luò)的url地址 */
        URL url = null;
        /** http連接 */
        // HttpURLConnection httpConn = null;
        /**//** 輸入流 */
        BufferedReader in = null;
        StringBuffer sb = new StringBuffer();
        try {
            url = new URL(urlStr);
            in = new BufferedReader(new InputStreamReader(url.openStream(), StandardCharsets.UTF_8));
            String str = null;
            while ((str = in.readLine()) != null) {
                sb.append(str);
            }
        } catch (Exception ex) {
            System.out.println("輸入異常！");
        } finally {
            try {
                if (in != null) {
                    in.close();
                }
            } catch (IOException ex) {
                System.out.println("輸出異常！");
            }
        }
//        String result = sb.toString();
//        JSONObject results = JSONObject.fromObject(result);
        // System.out.println(result);
//        return results;
        return sb;
    }
    
    /**
     * post 方法訪問
     * 
     * @param urls
     * @param paraem
     * @return
     * @throws MalformedURLException
     */
    public static String getURLPostContent(String urls, String paraem) {

        String result = null;// 接收輸出流

        // 要訪問的url地址
        try {
            URL url = new URL(urls);

            // 連接訪問地址
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();// 因?yàn)槭莗ost，所以用httpUrl接收
            // 設(shè)置參數(shù) 注意連接上后要先設(shè)置參數(shù)在做其他操作
            connection.setDoInput(true);// 向互聯(lián)網(wǎng)讀取數(shù)據(jù)，設(shè)置為true
            connection.setDoOutput(true);// 向互聯(lián)網(wǎng)傳遞數(shù)據(jù)，設(shè)置為true
            connection.setUseCaches(false);
            connection.addRequestProperty("encoding", "UTF-8");
//             connection.addRequestProperty("Content-Type",
//             "application/www-form-urlencoded;charset=utf-8");
            // 設(shè)定使用方法 必須先設(shè)置參數(shù)在做其他
            connection.setRequestMethod("POST");
            // 輸出流 將條件輸入到請求地址 注意在請求的時(shí)候一定是先寫入在寫出
            OutputStream os = connection.getOutputStream();
            OutputStreamWriter osw = new OutputStreamWriter(os,"utf-8");

            BufferedWriter bw = new BufferedWriter(osw);

            bw.write(paraem);// 對服務(wù)器輸出
            bw.flush();
            bw.close();
            osw.close();
            os.close();

            // 獲取到輸入輸出流 包裝
            InputStream is = connection.getInputStream();
            InputStreamReader isr = new InputStreamReader(is);
            BufferedReader br = new BufferedReader(isr);

            // 輸入
            String line;
            StringBuilder builder = new StringBuilder();
            while ((line = br.readLine()) != null) {
                // 填充
                builder.append(line);
            }
            // 關(guān)閉流
            br.close();
            isr.close();
            is.close();
            result = builder.toString();
            System.out.println(result);
        } catch (MalformedURLException e) {
            System.out.println("連接失敗！");
            e.printStackTrace();
        } catch (IOException e) {
            System.out.println("數(shù)據(jù)導(dǎo)入異常");
            e.printStackTrace();
        }
        // 轉(zhuǎn)換成json格式 返回回去
        return result;
    }
    
    /**
     * 帶證書請求
     */
    public static String doRefundPost(String url,String xmlData) throws Exception {
        KeyStore keyStore = KeyStore.getInstance("PKCS12");
//        URL save = Thread.currentThread().getContextClassLoader().getResource("ftl/apiclient_cert.p12");
//        String str = save.toString();
        File file = ResourceUtils.getFile("classpath:ftl/apiclient_cert.p12");
        FileInputStream instream = new FileInputStream(file);//P12文件目錄  寫證書的項(xiàng)目路徑
        try {
            keyStore.load(instream, WXUtil.MCHID.toCharArray());//這里寫密碼..默認(rèn)是你的MCHID 證書密碼
        } finally {
            instream.close();
        }
 
 
        SSLContext sslcontext = SSLContexts.custom()
                .loadKeyMaterial(keyStore, WXUtil.MCHID.toCharArray())//這里也是寫密碼的
                .build();
 
        SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(sslcontext);
        CloseableHttpClient httpclient = HttpClients.custom()
                .setSSLSocketFactory(sslsf)
                .build();
        try {
            HttpPost httpost = new HttpPost(url); // 設(shè)置響應(yīng)頭信息
            httpost.addHeader("Connection", "keep-alive");
            httpost.addHeader("Accept", "*/*");
            httpost.addHeader("Content-Type", "application/x-www-form-urlencoded; charset=UTF-8");
            httpost.addHeader("Host", "api.mch.weixin.qq.com");
            httpost.addHeader("X-Requested-With", "XMLHttpRequest");
            httpost.addHeader("Cache-Control", "max-age=0");
            httpost.addHeader("User-Agent", "Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.0) ");
            httpost.setEntity(new StringEntity(xmlData, "UTF-8"));
            CloseableHttpResponse response = httpclient.execute(httpost);
            try {
                HttpEntity entity = response.getEntity();
 
                String returnMessage = EntityUtils.toString(response.getEntity(), "UTF-8");
                EntityUtils.consume(entity);
                return returnMessage; //返回后自己解析結(jié)果
            } finally {
                response.close();
            }
        } finally {
            httpclient.close();
        }
    }
    
    /**
     * 上傳二進(jìn)制文件
     * @param graphurl 接口地址
     * @param file 圖片文件
     * @return
     */
    public static String uploadFile(String graphurl,MultipartFile file) {
        String line = null;//接口返回的結(jié)果
        try {
            // 換行符
            final String newLine = "\r\n";
            final String boundaryPrefix = "--";
            // 定義數(shù)據(jù)分隔線
            String BOUNDARY = "========7d4a6d158c9";
            // 服務(wù)器的域名
            URL url = new URL(graphurl);
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            // 設(shè)置為POST情
            conn.setRequestMethod("POST");
            // 發(fā)送POST請求必須設(shè)置如下兩行
            conn.setDoOutput(true);
            conn.setDoInput(true);
            conn.setUseCaches(false);
            // 設(shè)置請求頭參數(shù)
            conn.setRequestProperty("connection", "Keep-Alive");
            conn.setRequestProperty("Charsert", "UTF-8");
            conn.setRequestProperty("Content-Type","multipart/form-data; boundary=" + BOUNDARY);
            conn.setRequestProperty("User-Agent","Mozilla/5.0 (iPhone; CPU iPhone OS 11_0 like Mac OS X) AppleWebKit/604.1.38 (KHTML, like Gecko) Version/11.0 Mobile/15A372 Safari/604.1");
            OutputStream out = new DataOutputStream(conn.getOutputStream());
 
            // 上傳文件
            StringBuilder sb = new StringBuilder();
            sb.append(boundaryPrefix);
            sb.append(BOUNDARY);
            sb.append(newLine);
            // 文件參數(shù),photo參數(shù)名可以隨意修改
            sb.append("Content-Disposition: form-data;name=\"image\";filename=\""
                    + "https://api.weixin.qq.com" + "\"" + newLine);
            sb.append("Content-Type:application/octet-stream");
            // 參數(shù)頭設(shè)置完以后需要兩個(gè)換行，然后才是參數(shù)內(nèi)容
            sb.append(newLine);
            sb.append(newLine);
 
            // 將參數(shù)頭的數(shù)據(jù)寫入到輸出流中
            out.write(sb.toString().getBytes());
 
            // 讀取文件數(shù)據(jù)
            out.write(file.getBytes());
            // 最后添加換行
            out.write(newLine.getBytes());
 
            // 定義最后數(shù)據(jù)分隔線，即--加上BOUNDARY再加上--。
            byte[] end_data = (newLine + boundaryPrefix + BOUNDARY
                    + boundaryPrefix + newLine).getBytes();
            // 寫上結(jié)尾標(biāo)識
            out.write(end_data);
            out.flush();
            out.close();
            // 定義BufferedReader輸入流來讀取URL的響應(yīng)
            BufferedReader reader = new BufferedReader(new InputStreamReader(
                    conn.getInputStream()));
            while ((line = reader.readLine()) != null) {
                return line;
            }
        } catch (Exception e) {
            System.out.println("發(fā)送POST請求出現(xiàn)異常！" + e);
        }
        return line;
    }
    
    /**
     * 傳遞jsonhttp請求
     * @param url
     * @param json
     * @param fileName
     * @param targetPath
     * @return
     */
    public String httpPostWithJSON(String url, String json) {
        String result = "";
        CloseableHttpResponse response = null;
        CloseableHttpClient httpClient = null;

        try {
            httpClient = HttpClients.createDefault();
            HttpPost httpPost = new HttpPost(url);
            httpPost.addHeader(HTTP.CONTENT_TYPE, "application/json");
            StringEntity se = new StringEntity(json);
            se.setContentType("application/json");
            se.setContentEncoding(new BasicHeader(HTTP.CONTENT_TYPE, "UTF-8"));
            httpPost.setEntity(se);

            response = httpClient.execute(httpPost);
            if (response != null) {
                HttpEntity resEntity = response.getEntity();
                if (resEntity != null) {
                    InputStream instreams = resEntity.getContent();

                }
            }
            return result;
        } catch (Exception e) {
            e.printStackTrace();
            return e.getMessage();
        } finally {
            if (null != response) {
                try {
                    response.close();
                } catch (Exception e1) {
                    e1.printStackTrace();
                }
            }
        }
    }
}