调试的时候发现有类似如下报错：

JSON parse error: Cannot construct instance of `xxx` (although at least one Creator exists): cannot deserialize from Object value (no delegate- or property-based Creator); nested exception is com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot construct instance of `xxx` (although at least one Creator exists): cannot deserialize from Object value (no delegate- or property-based Creator)
 at [Source: (PushbackInputStream); line: 1, column: 2]

controller参数传了一个实体类：CategoryEntity

	@RequestMapping("/save")
    public R save(@RequestBody CategoryEntity category){
		categoryService.save(category);

        return R.ok();
    }

原本该实体是：

@Data
@TableName("pms_category")
public class CategoryEntity implements Serializable {
	...
}

在该实体类上加上@NoArgsConstructor（无参构造），就可以了：

@Data
@NoArgsConstructor
@TableName("pms_category")
public class CategoryEntity implements Serializable {
	...
}