小修改

src/main/java/jty/expressdistributionsystem/DTO/SendMessageDTO.java

@@ -4,8 +4,10 @@ import com.fasterxml.jackson.databind.annotation.JsonSerialize;
 import com.fasterxml.jackson.databind.ser.std.ToStringSerializer;
 import lombok.Data;
 
+import java.io.Serializable;
+
 @Data
-public class SendMessageDTO {
+public class SendMessageDTO implements Serializable {
     @JsonSerialize(using = ToStringSerializer.class)
     private Long Id;
 

src/main/java/jty/expressdistributionsystem/controller/AdminController.java

@@ -77,12 +77,6 @@ public class AdminController {
     // 管理员发送消息
     @PostMapping("/sendMessage")
     public Result<String> sendMessage(@RequestBody @NotNull SendMessageDTO sendMessageDTO) {
-        LambdaQueryWrapper<User> userLambdaQueryWrapper = new LambdaQueryWrapper<>();
-        userLambdaQueryWrapper.eq(User::getId, sendMessageDTO.getId());
-        User user = userService.getOne(userLambdaQueryWrapper);
-        if(user == null) {
-            return new Result<>(404, "用户不存在", "");
-        }
         Message message = SendMessageUtil.sendMessage(sendMessageDTO);
         messageService.save(message);
         return new Result<>(200, "发送成功", "");