一、微信小程序创建
先要去微信公众平台注册一个小程序，每个小程序都有相应的AppID(小程序ID)和AppSecret(小程序密钥)，它们是获取ACCESS_TOKEN所需要的。微信公众平台地址：
注册添加小程序后会取得AppID(小程序ID)和AppSecret(小程序密钥)：
二、依赖引入
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.41</version>
</dependency>
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpclient</artifactId>
</dependency>
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpmime</artifactId>
</dependency>
<dependency>
<groupId>com.google.code.gson</groupId>
<artifactId>gson</artifactId>
</dependency>三、核心代码
@RequestMapping("/QR")
@RestController
public class QRCodeController {
@RequestMapping("/getCode")
public void createQRCode(String param, String page, HttpServletResponse response) {
OutputStream stream = null;
try {
//获取AccessToken
String accessToken = getAccessToken();
//设置响应类型
response.setContentType("image/png");
String url = "https://api.weixin.qq.com/wxa/getwxacodeunlimit?access_token=" + accessToken;
//组装参数
Map<String, Object> paraMap = new HashMap<>();
//二维码携带参数 不超过32位 参数类型必须是字符串
paraMap.put("scene", param);
//二维码跳转页面
paraMap.put("page", page);
//二维码的宽度
paraMap.put("width", 450);
//自动配置线条颜色，如果颜色依然是黑色，则说明不建议配置主色调
paraMap.put("auto_color", false);
//是否需要透明底色， is_hyaline 为true时，生成透明底色的小程序码
paraMap.put("is_hyaline", false);
//执行post 获取数据流
byte[] result = HttpClientUtils.doImgPost(url, paraMap);
//输出图片到页面
response.setContentType("image/jpg");
stream = response.getOutputStream();
stream.write(result);
stream.flush();
stream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
/**
* 获取ACCESS_TOKEN
* 官方文档地址:https://developers.weixin.qq.com/miniprogram/dev/api-backend/open-api/access-token/auth.getAccessToken.html
* <p>
* 需要正确的 appid 和 secret 查看自己的微信开放平台
*/
public String getAccessToken() {
//这里需要换成你d的小程序appid
String appid = "wx141ac029d803ce4c";
//这里需要换成你的小程序secret
String appSecret = "bb245ef5f0add972bccd718087b7dd50";
//获取微信ACCESS_TOKEN 的Url
String accent_token_url = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=APPID&secret=APPSECRET";
String url = accent_token_url.replace("APPID", appid).replace("APPSECRET", appSecret);
//发送请求
String result = HttpClientUtils.doGet(url);
Map<String, Object> resultMap = (Map<String, Object>) JsonUtil.jsonToMap(result);
System.out.println("access_token------>" + resultMap.get("access_token").toString());
return resultMap.get("access_token").toString();
}
}public class HttpClientUtils {
private static final Logger LOGGER = LoggerFactory.getLogger(HttpClientUtils.class);
private static ConnectionSocketFactory plainsf = null;
private static LayeredConnectionSocketFactory sslsf = null;
private static Registry<ConnectionSocketFactory> registry = null;
private static PoolingHttpClientConnectionManager cm = null;
private static HttpRequestRetryHandler httpRequestRetryHandler = null;
private static RequestConfig requestConfig = null;
private static CloseableHttpClient httpClient = null;
static {
plainsf = PlainConnectionSocketFactory.getSocketFactory();
sslsf = SSLConnectionSocketFactory.getSocketFactory();
registry = RegistryBuilder.<ConnectionSocketFactory>create()
.register("http", plainsf)
.register("https", sslsf)
.build();
cm = new PoolingHttpClientConnectionManager(registry);
// 最大连接数
cm.setMaxTotal(30);
// 每个路由基础的连接
cm.setDefaultMaxPerRoute(10);
//请求重试处理
httpRequestRetryHandler = new HttpRequestRetryHandler() {
@Override
public boolean retryRequest(IOException exception, int executionCount, HttpContext context) {
if (executionCount >= 5) {// 如果已经重试了5次，就放弃
return false;
}
if (exception instanceof NoHttpResponseException) {// 如果服务器丢掉了连接，那么就重试
return true;
}
if (exception instanceof SSLHandshakeException) {// 不要重试SSL握手异常
return false;
}
if (exception instanceof InterruptedIOException) {// 超时
return false;
}
if (exception instanceof UnknownHostException) {// 目标服务器不可达
return false;
}
if (exception instanceof ConnectTimeoutException) {// 连接被拒绝
return false;
}
if (exception instanceof SSLException) {// ssl握手异常
return false;
}
HttpClientContext clientContext = HttpClientContext.adapt(context);
HttpRequest request = clientContext.getRequest();
// 如果请求是幂等的，就再次尝试
if (!(request instanceof HttpEntityEnclosingRequest)) {
return true;
}
return false;
}
};
requestConfig = RequestConfig.custom()
.setConnectionRequestTimeout(5000)
.setConnectTimeout(5000)
.setSocketTimeout(5000)
.build();
httpClient = HttpClients.custom()
.setConnectionManager(cm)
.setRetryHandler(httpRequestRetryHandler)
.build();
}
/**
* get请求
*
* @param url 访问ur
* @return
*/
public static String doGet(String url) {
String result = null;
CloseableHttpResponse response = null;
HttpGet httpget = new HttpGet(url);
try {
String resultEnc = "UTF-8";
httpget.setConfig(requestConfig);
response = httpClient.execute(httpget, HttpClientContext.create());
result = EntityUtils.toString(response.getEntity(), resultEnc);
} catch (Exception e) {
LOGGER.error("get请求 doPost", e);
return result;
} finally {
if (null != response) {
try {
response.close();
} catch (IOException e) {
LOGGER.error("get请求 doPost IOException", e);
}
}
httpget.abort();
}
return result;
}
/**
* 获取数据流
*
* @param url
* @param paraMap
* @return
*/
public static byte[] doImgPost(String url, Map<String, Object> paraMap) {
byte[] result = null;
HttpPost httpPost = new HttpPost(url);
httpPost.addHeader("Content-Type", "application/json");
try {
// 设置请求的参数
JSONObject postData = new JSONObject();
for (Map.Entry<String, Object> entry : paraMap.entrySet()) {
postData.put(entry.getKey(), entry.getValue());
}
httpPost.setEntity(new StringEntity(postData.toString(), "UTF-8"));
HttpClient httpClient = HttpClientBuilder.create().build();
HttpResponse response = httpClient.execute(httpPost);
HttpEntity entity = response.getEntity();
result = EntityUtils.toByteArray(entity);
} catch (ConnectionPoolTimeoutException e) {
e.printStackTrace();
} catch (ConnectTimeoutException e) {
e.printStackTrace();
} catch (SocketTimeoutException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
} finally {
httpPost.releaseConnection();
}
return result;
}
}public class JsonUtil {
private static Gson gson = new Gson();
public static Map<?, ?> jsonToMap(String jsonStr) {
Map<?, ?> objMap = null;
if (gson != null) {
Type type = new com.google.gson.reflect.TypeToken<Map<?, ?>>() {
}.getType();
objMap = gson.fromJson(jsonStr, type);
}
return objMap;
}
}四、效果展示
