JAVA-HTTP-生成微信小程序二维码，5种实现方式

package com.tiangang.service; import com.alibaba.fastjson.JSONObject; import kong.unirest.Unirest; import okhttp3.OkHttpClient; import okhttp3.Request; import okhttp3.RequestBody; import okhttp3.Response; import org.apache.http.HttpResponse; import org.apache.http.client.methods.HttpPost; import org.apache.http.entity.StringEntity; import org.apache.http.impl.client.CloseableHttpClient; import org.apache.http.impl.client.HttpClientBuilder; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.core.ParameterizedTypeReference; import org.springframework.http.HttpEntity; import org.springframework.http.HttpMethod; import org.springframework.stereotype.Service; import org.springframework.web.client.RestTemplate; import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.PrintWriter; import java.net.HttpURLConnection; import java.net.URL; import java.util.HashMap; import java.util.Map; /** * 作者：天罡gg * 作者博客主页：https://blog.csdn.net/scm_2008 * 博文地址：https://blog.csdn.net/scm_2008/article/details/128764936 * 有任何问题，欢迎大家私信联系或微信联系. */ @Service public class WechatService { @Autowired private RestTemplate restTemplate; private String wechatQrcodeUrl = "https://api.weixin.qq.com/wxa/getwxacodeunlimit?access_token="; private String wechatAccessTokenUrl = "https://api.weixin.qq.com/cgi-bin/token?appid=%s&secret=%s&grant_type=client_credential"; private String appid = "替换成你的appid"; private String secret = "替换成你的secret"; private String accessTokenCache; // 自行配置：正式版为 "release"，体验版为 "trial"，开发版为 "develop"。默认是正式版。 private String envVersion = "trial"; public String generateWechatRrCode(Integer mode) { // 当前登录账号 String accountId = "123456"; if (accessTokenCache == null) { accessTokenCache = getAccessToken(); } String url = wechatQrcodeUrl + accessTokenCache; Map<String, Object> body = new HashMap<>(); // 场景码，请根据业务场景与【前端】约定 body.put("scene", String.format("a=%s", accountId)); body.put("env_version", envVersion); // 透明 body.put("is_hyaline", true); byte[] bytes = null; switch (mode) { case 1: bytes = getWechatQrcodeByHttpURL(url, body); break; case 2: bytes = getWechatQrcodeByHttpClient(url, body); break; case 3: bytes = getWechatQrcodeByOkhttp3(url, body); break; case 4: bytes = getWechatQrcodeByUnirest(url, body); break; case 5: bytes = getWechatQrcodeByRestTemplate(url, body); break; } if (bytes == null) { return "null"; } String error = new String(bytes); if (error.contains("errcode")) { return error; } // 保存到本地 saveQrCodeToLocal(bytes,mode); return "ok"; } // 获取access_token public String getAccessToken() { String url = String.format(wechatAccessTokenUrl, appid, secret); Map<String, String> responseBody = restTemplate.exchange(url, HttpMethod.GET, null, new ParameterizedTypeReference<Map<String, String>>() {}).getBody(); if (responseBody == null || responseBody.get("errcode") != null) { // 获取失败 System.out.println("getAccessToken失败：" + (responseBody == null ? "null" : responseBody.toString())); return null; } return responseBody.get("access_token"); } // 一、原生HttpURLConnection方式 public byte[] getWechatQrcodeByHttpURL(String url, Map<String, Object> body) { HttpURLConnection httpURLConnection = null; try { httpURLConnection = (HttpURLConnection) new URL(url).openConnection(); httpURLConnection.setRequestMethod("POST"); // 发送POST请求必须设置如下两行 httpURLConnection.setDoOutput(true); httpURLConnection.setDoInput(true); // 获取URLConnection对象对应的输出流 PrintWriter printWriter = new PrintWriter(httpURLConnection.getOutputStream()); // 发送请求参数 printWriter.write(JSONObject.toJSONString(body)); // flush输出流的缓冲 printWriter.flush(); //开始获取数据 try (InputStream inputStream = httpURLConnection.getInputStream(); ByteArrayOutputStream out = new ByteArrayOutputStream()) { byte[] buffer = new byte[1024]; int len = -1; while ((len = inputStream.read(buffer)) != -1) { out.write(buffer, 0, len); } return out.toByteArray(); } } catch (Exception e) { e.printStackTrace(); } finally { if (httpURLConnection != null) { httpURLConnection.disconnect(); } } return null; } // 二、apache.httpclient方式 public byte[] getWechatQrcodeByHttpClient(String url, Map<String, Object> body) { CloseableHttpClient httpClient = HttpClientBuilder.create().build(); HttpPost httpPost = new HttpPost(url); try { StringEntity entity = new StringEntity(JSONObject.toJSONString(body)); entity.setContentType("image/png"); httpPost.setEntity(entity); HttpResponse response = httpClient.execute(httpPost); try (InputStream inputStream = response.getEntity().getContent(); ByteArrayOutputStream out = new ByteArrayOutputStream()) { byte[] buffer = new byte[1024]; int len = -1; while ((len = inputStream.read(buffer)) != -1) { out.write(buffer, 0, len); } return out.toByteArray(); } } catch (Exception e) { e.printStackTrace(); } return null; } // 三、okhttp3方式 public byte[] getWechatQrcodeByOkhttp3(String url, Map<String, Object> body) { OkHttpClient client = new OkHttpClient().newBuilder().build(); okhttp3.MediaType mediaType = okhttp3.MediaType.parse("application/json"); RequestBody requestBody = RequestBody.create(mediaType, JSONObject.toJSONString(body)); Request request = new Request.Builder().url(url).method("POST", requestBody).build(); try { Response response = client.newCall(request).execute(); if (response.isSuccessful()) { return response.body().bytes(); } } catch (IOException e) { e.printStackTrace(); } return null; } // 四、Unirest方式 public byte[] getWechatQrcodeByUnirest(String url, Map<String, Object> body) { return Unirest.post(url).body(JSONObject.toJSONString(body)).asBytes().getBody(); } // 五、restTemplate方式 public byte[] getWechatQrcodeByRestTemplate(String url, Map<String, Object> body) { return restTemplate.exchange(url, HttpMethod.POST, new HttpEntity<>(body, null), byte[].class).getBody(); } // 保存到本地 private void saveQrCodeToLocal(byte[] bytes, Integer mode) { try { InputStream inputStream = new