Java实现微信公众号消息推送

0. 测试准备工作

微信公众平台：https://mp.weixin.qq.com/debug/cgi-bin/sandboxinfo?action=showinfo&t=sandbox/index

1. 获取access_token

public String getAccessToken() {
    String url = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=" + appid + "&secret=" + secret;
    String response = restTemplate.getForObject(url, String.class);
    JSONObject object = JSONObject.parseObject(response);
    String accessToken = object.getString("access_token");
    return accessToken;
}

2. 通过微信接口获得微信公众号订阅者的openid

获取用户列表文档：https://developers.weixin.qq.com/doc/offiaccount/User_Management/Getting_a_User_List.html

public List<String> getOpenIdsFromWX(String accessToken) {
   // https://api.weixin.qq.com/cgi-bin/user/get?access_token=ACCESS_TOKEN&next_openid=NEXT_OPENID
    String url = "https://api.weixin.qq.com/cgi-bin/user/get?access_token=" + accessToken;
    ResponseEntity<String> response = restTemplate.postForEntity(url, null, String.class);
    JSONObject object = JSONObject.parseObject(response.getBody());
    List<String> openIds = JSONObject.parseArray(object.getJSONObject("data").getString("openid"), String.class);
    return openIds;
}

{
    "total": 2,
    "count": 2,
    "data": {
        "openid": [
            "oDoMF58rOTDxUCCiIjh3H0gkg0ek",
            "oDoMF51KUpL7WwPzdZZHYV5ChC_c"
        ]
    },
    "next_openid": "oDoMF51KUpL7WwPzdZZHYV5ChC_c"
}

3. 消息推送

模板消息文档：https://developers.weixin.qq.com/doc/offiaccount/Message_Management/Template_Message_Interface.html

public void sendMessage(String templateId, Map<String, WXMessage> data) {
    String accessToken = getAccessToken();
    List<String> openIds = getOpenIdsFromWX(accessToken);
    String url = "https://api.weixin.qq.com/cgi-bin/message/template/send?access_token=" + accessToken;
    Map<String, Object> body = new HashMap<>();
    body.put("template_id", templateId);
    body.put("data", data);
    for (String openId : openIds) {
        body.put("touser", openId);
        ResponseEntity<String> responseEntity = restTemplate.postForEntity(url, body, String.class);
        if (responseEntity.getStatusCode() != HttpStatus.OK) {
            System.out.println("推送消息异常: " + openId);
        }
    }
}