update 优化代码小优化项

- ex.getMessage() 判空后再 contains，避免异常处理器自身 NPE
- 抄送历史任务为空时改为明确的 ServiceException；当前任务办理人查询改为 ID 去重后批量远程查
- 流程图提示里用户 ID 去重，部门名称从循环内逐条Dubbo 调用改为一次批量查询

ruoyi-gateway/src/main/java/org/dromara/gateway/handler/GatewayExceptionHandler.java

@@ -34,8 +34,9 @@ public class GatewayExceptionHandler {
     public void handle(HttpServletRequest request, HttpServletResponse response, Throwable ex) throws IOException {
         int code;
         String msg;
+        String exceptionMessage = ex.getMessage();
         if ("NotFoundException".equals(ex.getClass().getSimpleName())
-            || ex.getMessage().contains("Unable to find instance")) {
+            || (exceptionMessage != null && exceptionMessage.contains("Unable to find instance"))) {
             code = HttpStatus.NOT_FOUND;
             msg = "服务未找到";
         } else if (ex instanceof ResponseStatusException responseStatusException) {
@@ -46,7 +47,7 @@ public class GatewayExceptionHandler {
             msg = "内部服务器错误";
         }
 
-        log.error("[网关异常处理]请求路径:{},异常信息:{}", request.getRequestURI(), ex.getMessage(), ex);
+        log.error("[网关异常处理]请求路径:{},异常信息:{}", request.getRequestURI(), exceptionMessage, ex);
         writeJson(response, code, msg);
     }