【Java】企业微信机器人自动发送群消息

先在群里添加机器人，然后获取机器人的webhook地址：

假设webhook是：https://qyapi.weixin.qq.com/cgi-bin/webhook/send?key=693a91f6-7xxx-4bc4-97a0-0ec2sifa5aaa

2.有多种方式发送群消息，可以采用curl，也可以采用发送https请求的方式，我这里采用okhttp发送http请求，pom如下：

<!-- https://mvnrepository.com/artifact/com.squareup.okhttp3/okhttp -->
        <dependency>
            <groupId>com.squareup.okhttp3</groupId>
            <artifactId>okhttp</artifactId>
            <version>4.9.0</version>
        </dependency>

调用okhttp核心代码如下：

/**
*	@content：要发送的消息
*	WECHAT_GROUP：机器人的webhook
*/
public String callWeChatBot(String content) {
        OkHttpClient client = new OkHttpClient()
                .newBuilder()
                .build();
        MediaType mediaType = MediaType.parse("application/json");
        RequestBody body = RequestBody.create(content,mediaType);
        Request request = new Request.Builder()
                .url(WECHAT_GROUP)
                .method("POST", body)
                .addHeader("Content-Type", "application/json")
                .build();
        Response response = null;
        try {
            response = client.newCall(request).execute();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return response.message();
    }

3.生成核心方法的参数，如果发送markdown格式的消息：

 /**
     *  域账号+名字
     * @param jobNumber
     * @param applyType 数据投递 topic 支持
     * @return
     */
    public  String generalBotBodyInfo(String jobNumber,String applyType) {
        String content = "【采集-消息主题维护通知】\n \n" +
                ">告警名称：<font color=\\\"info\\\">" + "topic队列申请工单"+ "</font>\n " +
                ">项目：<font color=\\\"info\\\">" + "data-delivery" + "</font>\n" +
                ">任务描述：<font color=\\\"info\\\">" + jobNumber +"提交了"+applyType+"，请及时查看"+ "</font>\n " +
                ">任务状态：<font color=\\\"info\\\">" + "申请" + "</font>\n" +
                ">时间：<font color=\\\"info\\\">" + new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date()) + "</font>";

        String textTemplate = "{\n" +
                "    \"msgtype\": \"markdown\",\n" +
                "    \"markdown\": {\n" +
                "        \"content\": \"" + content + "\",\n" +
                "    }\n" +
                "}";
        return textTemplate;
    }

如果发送text格式的消息：

public static String generalBotBodyAT() {
        String textTemplate = "{\n" +
                "    \"msgtype\": \"text\",\n" +
                "    \"text\": {\n" +
                "        \"content\": \"今天下午大暴雨\",\n" +
                "        \"mentioned_list\":[\"@all\"],\n" +
                "    }\n" +
                "}";
        return textTemplate;
    }

如果发送图片，不能超过2M，支持的格式为JPG,PNG格式:

public static String generalBotBodyImage() {
        String base64 = "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";
        String md5 = "862715fb36992d6746641ff02ee85b8c";

        String textTemplate = "{\n" +
                "    \"msgtype\": \"image\",\n" +
                "    \"image\": {\n" +
                "        \"base64\": \"" + base64 + "\",\n" +
                "        \"md5\": \"" + md5 + "\"\n" +
                "    }\n" +
                "}";
        return textTemplate;
    }

发送图片需要对图片进行base64编码并计算图片的md5值，把计算的方法也一并献上，需要注意图片不要过大，不然base64编码的结果会超级长，甚至超过String的最大长度，java.util.Base64这个工具类有现成的，直接用就行

public static String getFileBase64(String path){
        try {
            FileInputStream inputStream = new FileInputStream(new File(path));
            byte [] bs = new byte[inputStream.available()];
            inputStream.read(bs);
            return Base64.getEncoder().encodeToString(bs);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }catch (IOException e){
            e.printStackTrace();
        }
        return null;
    }

计算md5值方法多种多样，如果你发送的图片是固定的，建议算好后直接用常量保存就行，比如我发送的是个表情包，就提前算好了。如果你是windows系统可以用好压之类的工具直接查看文件的md5，如果你是mac os系统，可以这样：

如果图片是动态的，可以用java现成的工具类直接计算它的md5，pom如下：

<!-- https://mvnrepository.com/artifact/commons-codec/commons-codec -->
        <dependency>
            <groupId>commons-codec</groupId>
            <artifactId>commons-codec</artifactId>
            <version>1.10</version>
        </dependency>

代码：

public static String getFileMD5(String path) {
        try {
            FileInputStream inputStream = new FileInputStream(new File(path));
            byte[] buf = new byte[inputStream.available()];
            inputStream.read(buf);
            return DigestUtils.md5Hex(buf);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }