springboot~自定義valid及DefaultGroupSequenceProvider的作用

spring一切都可以基于注解來實例，像緩存，校驗，字段映射，動態代理等等，今天主要說一下自定義的校驗及校驗的組關聯。

• 自定義注解，判斷name需要以"管理員"結尾

@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
@Constraint(validatedBy = PrefixAdminValidator.class)
@Documented
public @interface PrefixAdmin {
    String message() default "必須以'角色'結尾";
    //這兩個屬性必須有
    Class<?>[] groups() default {};
    Class<? extends Payload>[] payload() default {};
}
@Component
public class PrefixAdminValidator implements ConstraintValidator<PrefixAdmin, String> {

    @Override
    public void initialize(PrefixAdmin constraintAnnotation) {
    }

    @Override
    public boolean isValid(String value, ConstraintValidatorContext context) {
        return value.endsWith("角色");
    }
}

• 然后有個需求，只有字段manager為true時，才進行PrefixAdminValidator的校驗，這時我們可以通過DefaultGroupSequenceProvider組依賴來實現

/**
 * 校驗的依賴，當isManager為true為，PrefixAdmin注解才有效.
 */
public class RoleProvider implements DefaultGroupSequenceProvider<RoleDTO> {
    @Override
    public List<Class<?>> getValidationGroups(RoleDTO object) {
        List<Class<?>> defaultGroupSequence = new ArrayList<>();

        defaultGroupSequence.add(RoleDTO.class); //注意這里不要寫錯
        if (object != null && object.isManager()) {
            defaultGroupSequence.add(RoleDTO.CheckManagerGroup.class);
        }
        return defaultGroupSequence;
    }
}

• 實體在字段上添加對接的注解

@Data
@GroupSequenceProvider(RoleProvider.class)
@ApiModel("角色DTO")
public class RoleDTO {
    private String id;

    @PrefixAdmin(groups = CheckManagerGroup.class)
    private String name;

    private boolean manager;

    public interface CheckManagerGroup {
    }
}

• 控制器請求體添加@Valid

    @ApiOperation("新增")
	@PostMapping("add")
	@Transactional(rollbackFor = Exception.class)
	public CommonResult add(@Valid @RequestBody RoleDTO roleDTO) {
		if (roleDao.selectOne(new QueryWrapper<Role>().lambda().eq(Role::getName, roleDTO.getName())) != null) {
			return CommonResult.clientFailure(String.format("%s已經存在", roleDTO.getName()));
		}
		Role role = new Role();
		CopyUtils.copyProperties(roleDTO, role);
		roleDao.insert(role);
		updateRolePermissions(roleDTO.getPermissionIdList(), role);
		return CommonResult.ok();
	}

• 測試數據
  
• 結果響應

{
    "code": 400,
    "message": "name必須以'角色'結尾",
    "data": null
}