我在使用JavaREST模板发送请求体中的原始数据时遇到了困难，所以我在这里添加了这段代码以供将来参考（我是java编码的新手）。
下面的代码为我发送消息到微软团队频道工作

public JSONObject sendMessage(String team_ID, String channel_ID){
        JSONObject res =null;        
        RestTemplate restTemplate = new RestTemplate();
        String url="https://graph.microsoft.com/beta/teams/"+team_ID+"/channels/"+channel_ID+"/messages";
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_JSON);                
        String token = "xxxxxxxxxx";
        headers.set("Authorization","Bearer "+token);

         // This  didn't worked 
        /*MultiValueMap<String, Object> map = new LinkedMultiValueMap<String, Object>();
        map.add("content", "Welcome to General channel message sent via intellij IDE");

        MultiValueMap<String, String> map1= new LinkedMultiValueMap<String, String>();
        map1.add("content", "Welcome to General channel message sent via intellij IDE");
        //map.add("body", "Welcome to General channel message sent via intellij IDE");*/

         // This one also didn't worked 
        //JSONObject jsonObject = new JSONObject();
        //jsonObject.put("body", "{ \"body\": {\"content\":\"Welcome to General channel message sent via intellij IDE  using java coding & http rest-Template\"}}");

        // This one also didn't worked 
        //JSONObject jsonObject = new JSONObject();
        //jsonObject.put("body", "{\"content\":\"Welcome to General channel message sent via intellij IDE  using java coding & http rest-Template\"}");

        // This one worked
        String requestJson = "{ \"body\": {\"content\":\"Welcome to General channel message sent via intellij IDE using java coding & http rest-Template\"}}";

        // HttpEntity<String> request = new HttpEntity<String>(jsonObject.toString(),headers);
        HttpEntity<String> request = new HttpEntity<String>(requestJson,headers);
        ResponseEntity<String> response=null;
        try {
            response = restTemplate.postForEntity(url, request, String.class);
            res= new JSONObject(response.getBody());
            System.out.println(res);
        }catch(Exception e){
            e.printStackTrace();
        }
        return  res;
    }