修复转移群主时可能报NPE的问题

core/src/main/java/com/wecloud/im/service/impl/ImGroupServiceImpl.java

@@ -366,15 +366,15 @@ public class ImGroupServiceImpl implements ImGroupService {
         ImConversationMembers oldGroupOwner =
                 conversationMembersService.getOne(Wrappers.<ImConversationMembers>lambdaQuery().eq(ImConversationMembers::getFkConversationId,
                         conversation.getId()).eq(ImConversationMembers::getRole, GroupRoleEnum.OWNER.getCode()));
-        ImClient oldGroupOwnerClient = clientService.getById(oldGroupOwner.getFkClientId());
+
         // 获取新群主
         ImConversationMembers newGroupOwner =
                 conversationMembersService.getOne(Wrappers.<ImConversationMembers>lambdaQuery().eq(ImConversationMembers::getFkConversationId,
                         conversation.getId()).eq(ImConversationMembers::getClientId, newGroupOwnerUserId));
-
         if (newGroupOwner == null) {
             throw new BusinessException("新群主不在该群中");
         }
+        ImClient newGroupOwnerClient = clientService.getById(newGroupOwner.getFkClientId());
 
         if (oldGroupOwner != null) {
             if (oldGroupOwner.getClientId().equals(newGroupOwner.getClientId())) {
@@ -393,13 +393,13 @@ public class ImGroupServiceImpl implements ImGroupService {
         // 操作的client ID
         Map<String, Object> content = new HashMap<>();
         content.put("operator", newGroupOwner.getClientId());
-        ImMessage imMessage = MessageBuilder.buildEventMessage(MsgTypeEnum.CONVERSATION_NEW_CREATOR, imApplication, oldGroupOwnerClient, conversation, JsonUtils.encodeJson(content));
+        ImMessage imMessage = MessageBuilder.buildEventMessage(MsgTypeEnum.CONVERSATION_NEW_CREATOR, imApplication, newGroupOwnerClient, conversation, JsonUtils.encodeJson(content));
         imMessageService.save(imMessage);
         // 发送给在群内的成员
         List<ImConversationMembers> existMemberList =
                 conversationMembersService.list(Wrappers.<ImConversationMembers>lambdaQuery()
                         .eq(ImConversationMembers::getFkConversationId, conversation.getId()));
-        conversationService.sendMsgToMembers(conversation, existMemberList, oldGroupOwnerClient, imMessage, content);
+        conversationService.sendMsgToMembers(conversation, existMemberList, newGroupOwnerClient, imMessage, content);
 
         return true;
     }