Java 获取微信小程序二维码（指定启动页面和动态传入参数）

摘要：
Java 获取微信小程序二维码（指定启动页面和动态传入参数），Java 获取微信小程序二维码（指定启动页面和动态传入参数），Java 获取微信小程序二维码（指定启动页面和动态传入参数）
代码案例：

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Base64;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
 
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpGet;
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.HttpClients;
import org.apache.http.protocol.HTTP;
import org.apache.http.util.EntityUtils;
import org.apache.log4j.Logger;
 
import com.alibaba.fastjson.JSON;
import com.what21.server.common.integrate.wechat.WeChat;
 
public class WeChatApplet extends WeChat {
 
    static Logger logger = Logger.getLogger(WeChatApplet.class);
 
    /**
     * @return
     */
    public static Map<String, Object> getToken() {
        Map<String, Object> data = new HashMap<String, Object>();
        try {
            // ======================================================================//
            // 拼接调用微信的URL
            // grant_type：client_credential
            // appid：小程序
            // secret：小程序
            // ======================================================================//
            StringBuilder urlSb = new StringBuilder();
            urlSb.append("https://api.weixin.qq.com/cgi-bin/token");
            urlSb.append("?");
            urlSb.append("grant_type=%s&appid=%s&secret=%s");
            String tokenUrl = String.format(urlSb.toString(), "client_credential", MIN_APPID, MIN_APPSECRET);
            // ======================================================================//
            // 执行URL Get调用
            // ======================================================================//
            CloseableHttpClient httpClient = HttpClients.createDefault();
            HttpGet httpGet = new HttpGet(tokenUrl);
            HttpResponse httpResponse = httpClient.execute(httpGet);
            HttpEntity httpEntity = httpResponse.getEntity();
            String resultText = EntityUtils.toString(httpEntity, "utf-8");
            // ======================================================================//
            // 处理HTTP返回结果
            // ======================================================================//
            @SuppressWarnings("unchecked")
            Map<Object, Object> resultMap = JSON.parseObject(resultText, Map.class);
            if (resultMap != null) {
                if (resultMap != null && resultMap.size() > 0) {
                    // 合并2次调用结果
                    Set<Object> keySet = resultMap.keySet();
                    for (Object key : keySet) {
                        if (!data.containsKey(key)) {
                            data.put((String) key, resultMap.get(key));
                        }
                    }
                }
            }
        } catch (Exception e) {
            logger.error("fail to request wechat access token. [error={}]", e);
        }
        return data;
    }
 
    /**
     * @param accessToken
     * @param page
     * @param scene
     * @param width
     * @return
     */
    public static Map<String, Object> getMiniQrCode(String accessToken, String page, String scene, int width) {
        Map<String, Object> data = new HashMap<String, Object>();
        try {
            // ======================================================================//
            // 拼接调用微信的URL
            // ======================================================================//
            String url = "https://api.weixin.qq.com/wxa/getwxacodeunlimit?access_token=" + accessToken;
            Map<String, Object> paramsMap = new HashMap<>();
            paramsMap.put("page", page);
            paramsMap.put("scene", scene);
            paramsMap.put("width", width <= 0 ? 430 : width);
            paramsMap.put("auto_color", false);
            Map<String, Object> line_color = new HashMap<String, Object>();
            line_color.put("r", 0);
            line_color.put("g", 0);
            line_color.put("b", 0);
            paramsMap.put("line_color", line_color);
            logger.info("调用生成微信URL接口传参：" + paramsMap);
            // ======================================================================//
            // 执行URL Post调用
            // ======================================================================//
            CloseableHttpClient httpClient = HttpClients.createDefault();
            HttpPost httpPost = new HttpPost(url);
            httpPost.addHeader(HTTP.CONTENT_TYPE, "application/json");
            // 必须是json模式的 post
            String body = JSON.toJSONString(paramsMap);
            StringEntity entity = new StringEntity(body);
            entity.setContentType("image/png");
            httpPost.setEntity(entity);
            HttpResponse httpResponse = httpClient.execute(httpPost);
            HttpEntity httpEntity = httpResponse.getEntity();
            // ======================================================================//
            // 处理HTTP返回结果
            // ======================================================================//
            InputStream contentStream = httpEntity.getContent();
            byte[] bytes = toByteArray(contentStream);
            contentStream.read(bytes);
            // 返回内容
            data.put("qrLength", bytes.length);
            data.put("qrBytes", bytes);
            data.put("qrBytesEncoder", Base64.getEncoder().encodeToString(bytes));
        } catch (Exception e) {
            e.printStackTrace();
            logger.error("调用生成微信小程序码URL接口异常", e);
        }
        return data;
    }
 
    /**
     * @param input
     * @return
     * @throws IOException
     */
    public static byte[] toByteArray(InputStream input) throws IOException {
        ByteArrayOutputStream output = new ByteArrayOutputStream();
        copy(input, output);
        return output.toByteArray();
    }
 
    /**
     * @param input
     * @param output
     * @return
     * @throws IOException
     */
    public static int copy(InputStream input, OutputStream output) throws IOException {
        long count = copyLarge(input, output);
        if (count > 2147483647L) {
            return -1;
        }
        return (int) count;
    }
 
    /**
     * @param input
     * @param output
     * @return
     * @throws IOException
     */
    public static long copyLarge(InputStream input, OutputStream output) throws IOException {
        byte[] buffer = new byte[4096];
        long count = 0L;
        int n = 0;
        while (-1 != (n = input.read(buffer))) {
            output.write(buffer, 0, n);
            count += n;
        }
        return count;
    }
 
}
测试方法：

import java.io.FileOutputStream;
import java.util.Map;
 
public class WeChatAppletTest {
 
    /**
     * @param args
     */
    public static void main(String[] args) {
        String access_token = (String) WeChatApplet.getToken().get("access_token");
        Map<String, Object> data = WeChatApplet.getMiniQrCode(access_token, "pages/index/index",
                "btype=1&border=xxx",60);
        String qrBytesEncoder = (String) data.get("qrBytesEncoder");
        Integer qrLength = (Integer) data.get("qrLength");
        System.out.println(qrBytesEncoder);
        System.out.println(qrLength);
        byte[] qrBytes = (byte[]) data.get("qrBytes");
        saveToImg("d://qrcode.png",qrBytes);
    }
 
    /**
     * @param imgPath
     * @param bytes
     * @return
     */
    public static int saveToImg(String imgPath, byte[] bytes) {
        int stateInt = 1;
        try {
            FileOutputStream fos = new FileOutputStream(imgPath);
            fos.write(bytes);
            fos.flush();
            fos.close();
        } catch (Exception e) {
            stateInt = 0;
            e.printStackTrace();
        } finally {
        }
        return stateInt;
    }
 
}

 

 

转载：http://www.what21.com/u/10004/6756200547748968305.htm