用于某些特殊的参数校验

1.自定义注解

@Documented
@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
public @interface NotNull {
   //字段名称 
   String name() default "字段";
   //提示信息
   String message() default "不能为空";
}

 

2.被校验的实体

public class User {
    @NotNull(name="学号" message = "不能为空")
    public String id;
    @NotNull(name="姓名" message = "不能为空")
    public String name;
}

 

3.校验逻辑示例

public class ParamValid {
    public static check(Object obj) throws Throwable {
        Field[] fields = obj.getClass().getDeclaredFields();
        for (Field field : fields) {
            boolean note = field.isAnnotationPresent(NotNull.class);
            if (note) {
                NotNull notNull = field.getAnnotation(NotNull.class);
                 String annoName = notNull.name();
                 String annomessage = notNull.message();
                String fieldName = field.getName();
                ObjectMapper mapper=new ObjectMapper();
                String json = mapper.writeValueAsString(body);
                Object fileValue = new Gson().fromJson(json, Map.class).get(fieldName);
                if(StringUtils.isEmpty(fileValue ))){
                    throw new RuntimeException(annoName +annomessage);
                }
            }

        }
    }
}

  4.在需要处进行校验

ParamValid.check(obj);