Springboot parameter verification that must be won

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In the actual project, not only the front-end needs to check the required items, but also the back-end needs to check the relevant parameters to prevent illegal parameters from affecting the business. Next, let’s learn how to check the parameters in the Springboot project. . The version of Springboot in this article is 2.6.8

Introduce dependencies

If Springbootthe version is less than 2.3.x, the dependency spring-boot-starter-webwill be imported automatically hibernate-validator. If the Springboot version is greater than that 2.3.x, you need to manually introduce dependencies: Reminder: Version 7.xx may not work

<!-- https://mvnrepository.com/artifact/org.hibernate/hibernate-validator -->
<dependency>
    <groupId>org.hibernate</groupId>
    <artifactId>hibernate-validator</artifactId>
    <version>6.2.0.Final</version>
</dependency>
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Or directly introduce the scene starter of springboot

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-validation</artifactId>
            <version>2.7.0</version>
        </dependency>
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The difference between @Validated and @Valid

** Secondary encapsulation @Validatedof@Valid ** has been carried out, but the two have the following differences:

• ** @ValidatedProvide the grouping function, and different verification mechanisms can be adopted according to different groups during parameter verification. @Valid**No grouping function
• ** @ValidatedUsed on types, methods, and method parameters. But it cannot be used for member attributes (field),@Valid ** can be used for methods, constructors, method parameters and member attributes (field)
• A pojo class to be verified, which also includes the object properties to be verified, needs to be annotated ** on the object to be verified @Valid, in order to verify the member properties in the object to be verified,@Validated ** cannot be used here

Unified exception handling

If the verification fails, it will report MethodArgumentNotValidException or ConstraintViolationException

@RestControllerAdvice
public class ParamException {

    @ExceptionHandler({MethodArgumentNotValidException.class})
    @ResponseStatus(HttpStatus.BAD_REQUEST)
    public ResultReturn handleMethodArgumentNotValidException(MethodArgumentNotValidException ex) {
        BindingResult bindingResult = ex.getBindingResult();
        StringBuilder sb = new StringBuilder("校验失败:");
        for (FieldError fieldError : bindingResult.getFieldErrors()) {
            sb.append(fieldError.getField()).append("：").append(fieldError.getDefaultMessage()).append(", ");
        }
        String msg = sb.toString();
        return ResultReturnUtil.fail(ErrorCodeEnum.PARAM_ERROR.getCode(),msg);
    }

    @ExceptionHandler({ConstraintViolationException.class})
    @ResponseStatus(HttpStatus.BAD_REQUEST)
    public ResultReturn handleConstraintViolationException(ConstraintViolationException ex) {
        return ResultReturnUtil.fail(ErrorCodeEnum.PARAM_ERROR.getCode(),ex.getMessage());
    }
}
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We can define the error information to be returned in the enumeration

@Getter
@ToString
public enum ErrorCodeEnum {

    PARAM_ERROR(10001,"参数错误");

    private Integer code;

    private String msg;

    ErrorCodeEnum(Integer code, String msg) {
        this.code = code;
        this.msg = msg;
    }
}
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Another unified return format

@Data
public class ResultReturn implements Serializable {

    private static final long serialVersionUID = 5805792987639183304L;
    private Integer code;

    private String msg;

    private Object data;

    public ResultReturn(){
        super();
    }

    public ResultReturn(Integer code, String msg){
        this.code = code;
        this.msg = msg;
    }

    public ResultReturn(Integer code, String msg, Object data){
        this.code = code;
        this.msg = msg;
        this.data = data;
    }
}
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public class ResultReturnUtil {

    /**
     * 成功 返回默认码值
     * @param msg
     * @return
     */
    public static ResultReturn success(String msg){
        return new ResultReturn(0,msg);
    }

    /**
     * 成功  返回自定义码值
     * @param code
     * @param msg
     * @return
     */
    public static ResultReturn success(Integer code, String msg){
        return new ResultReturn(code,msg);
    }

    public static ResultReturn success(String msg, Object data){
        return  new ResultReturn(0,msg,data);
    }

    public static ResultReturn fail(String msg){
        return new ResultReturn(-1,msg);
    }

    public static ResultReturn fail(Integer code, String msg){
        return new ResultReturn(code,msg);
    }
}
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RequestBody parameter verification

当我们使用POST、PUT请求时会使用 @RequestBody+实体类 来接收参数。此时只需要给实体类加上**@Validated**注解就能实现自动参数校验。

@RestController
public class TestController {

    @PostMapping("/addUser")
    public Boolean addUser(@RequestBody @Validated User user){
        //忽略service处理相关业务
        return true;
    }
}
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那么具体到每个参数的校验则需要在实体类中处理。

@Data
public class User {

    private Long id;

    @NotBlank(message = "用户账号不能为空")
    @Length(min = 4, max = 10,message = "账号长度为4-10位")
    private String userName;

    @NotBlank(message = "密码不能为空")
    @Length(min = 6,max = 12,message = "密码长度为6-12位")
    private String password;

    @NotNull(message = "邮箱不能为空")
    @Email(message = "邮箱格式错误")
    private String email;
    /**
     * 性别 1为男生  2为女生
     */
    @Min(value = 1,message = "最小值为1")
    @Max(value = 2,message = "最大值为2")
    private Integer sex;

}
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先请求一次试试

requestParam/PathVariable参数校验

这种方式下参数都较少，必须在Controller类上标注**@Validated**注解，并在入参上声明约束注解

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接下来请求试一下

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特殊情况

也是上文提到的，pojo参数中有对象属性，那么要对这个对象中的属性校验该怎么做？

比如我这里有个学生类

@Data
public class Student {
    @NotBlank(message = "用户名不能为空")
    private String name;
    @Min(value = 10, message = "年龄不能小于10岁")
    private Integer age;

    @Email(message = "邮箱格式错误")
    private String email;

    @NotBlank(message = "班级名不能为空")
    private String className;

    @NotEmpty(message = "任课老师不能为空")
    @Size(min = 1, message = "至少有一个老师")
    private List<Teacher> teachers;
}
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@Data
public class Teacher {
    @NotBlank(message = "老师姓名不能为空")
    private String teacherName;
    @Min(value = 1, message = "学科类型从1开始计算")
    private Integer type;
}
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测试一下

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很明显这个type的值并不符合要求， 需要在学生类的教师属性上加上**@Valid**注解

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参数校验注解大全

注解

作用类型

解释

null是否

能通过验证

@AssertFalse

Boolean、boolean

该字段值为false时，验证才能通过

YES

@AssertTrue

Boolean、boolean

该字段值为true时，验证才能通过

YES

@DecimalMax

数字类型（原子和包装）

验证小数的最大值

@DecimalMax(value = "12.35")
private double money;
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YES

@DecimalMin

数字类型（原子和包装）

验证小数的最小值

YES

@Digits

数字类型（原子和包装）

验证数字的整数位和小数位的位数是否超过指定的长度

@Digits(integer = 2, fraction = 2)
private double money;
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YES

@Email

String

该字段为Email格式，才能通过

YES

@Future

时期、时间

验证日期是否在当前时间之后，否则无法通过校验

@Future
private Date date;
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YES

@FutureOrPresent

时期、时间

时间在当前时间之后 或者等于此时

YES

@Max

数字类型（原子和包装）

//该字段的最大值为18，否则无法通过验证
@Max(value = 18)
private Integer age;
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YES

@Min

数字类型（原子和包装）

同上，不能低于某个值否则无法通过验证

YES

@Negative

数字<0

YES

@NegativeOrZero

数字=<0

YES

@NotBlank

String 该注解用来判断字符串或者字符，只用在String上面

字符串不能为null,字符串trim()后也不能等于“”

NO

@NotEmpty

String、集合、数组、Map、链表List

不能为null，不能是空字符，集合、数组、map等size()不能为0；字符串trim()后可以等于“”

NO

@NotNull

任何类型

The value of the field using this annotation cannot be null, otherwise the verification will fail

NO

@Null

The modified field must be null during validation, otherwise the validation will fail

YES

@Past

time, date

Verify whether the date is before the current time, otherwise it cannot pass the verification, it must be a past time or date

YES

@PastOrPresent

time, date

Verify if date is before or equal to current time

YES

@Pattern

Used to verify whether the field matches the given regular

@Pattern(regexp = "正则")
private String name;
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YES

@Positive

Number > 0

YES

@PositiveOrZero

number>=0

YES

@Size

String String, collection Set, array Array, Map, List

修饰的字段长度不能超过5或者低于1
@Size(min = 1, max = 5)
private String name;
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The size() value of collections, arrays, maps, etc. must be within the specified range

    //只能一个
    @Size(min = 1, max = 1)
    private List<String> names;
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YES

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