Optional在SpringBoot中的实际应用

左手的ㄟ右手 2022-09-05 04:18 297阅读 0赞

## 第一步：实体类 ##

@Data
    @ToString
    public class User { 
        private Integer id;
    
        @NotBlank(message = "用户名不能为空")
        @Length(min = 6, max = 32, message = "用户名的长度需要在6~32之间")
        private String name;
    
        @Past(message = "出生日期必须早于当前日期")
        @DateTimeFormat(pattern = "yyyy-MM-dd")
        private LocalDate birth;
    
        @Email(
                regexp = "^[a-zA-Z0-9_.-]+@[a-zA-Z0-9-]+(\\.[a-zA-Z0-9-]+)*\\.[a-zA-Z0-9]{2,6}$",
                message = "邮件格式错误")
        private String email;
    
        @Size(min = 11, max = 11, message = "用户电话长度必须为11位")
        private String mobile;
    
        @NotNull(message = "用户等级不能为空")
        @Min(value = 1, message = "用户等级最小值为1")
        @Max(value = 6, message = "用户等级最大值为6")
        @Digits(integer = 1, fraction = 0, message = "用户等级必须为整数")
        private Integer level;
    
    }

## 第二步：定义BaseController ##

public class BaseController { 
        protected Optional<List<String>> valid(BindingResult result){ 
            if(result.hasErrors()){ 
                List<String> list = result.getAllErrors().stream()
                	.map(error -> error.getDefaultMessage())
                	.collect(Collectors.toList());
                return Optional.ofNullable(list);
            }
            return  Optional.empty();
        }
    }

## 第三步：定义控制器 ##

@RestController
    @RequestMapping("/user1")
    public class UserController extends BaseController{ 
    
        @PostMapping("/add")
        public void add(@Valid User user, BindingResult result) { 
            Optional<List<String>> op = valid(result);
            if(op.isPresent()){ 
                op.get().forEach(System.out::println);
            }
        }
    
    }

## 第四步：测试 ##

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