dependencies {
    implementation('org.springframework.boot:spring-boot-starter-validation')
    implementation('org.springframework.boot:spring-boot-starter-web')
}

public class User {
    @NotBlank
    @Size(max=10)
    private String name;
    private String password;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
}

// UserController.java，省略其他代碼
@RestController
public class UserController {
    @RequestMapping(value = "/validation/get", method = RequestMethod.GET)
    public ServiceResponse validateGet(@Validated User user) {
        ServiceResponse serviceResponse = new ServiceResponse();
        serviceResponse.setCode(0);
        serviceResponse.setMessage("test");
        return serviceResponse;
    }
}
// ServiceResponse.java，簡(jiǎn)單包含了code、message字段返回結(jié)果。
public class ServiceResponse {
    private int code;
    private String message;
    ... 省略getter、setter ...
}

// StartWithValidator.java
public class StartWithValidator implements ConstraintValidator<StartWithValidation, String> {
    private String start;
    @Override
    public void initialize(StartWithValidation constraintAnnotation) {
        start = constraintAnnotation.start();
    }
    @Override
    public boolean isValid(String value, ConstraintValidatorContext context) {
        if (!StringUtils.isEmpty(value)) {
            return value.startsWith(start);
        }
        return true;
    }
}
// StartWithValidation.java
@Documented
@Constraint(validatedBy = StartWithValidator.class)
@Target({METHOD, FIELD})
@Retention(RUNTIME)
public @interface StartWithValidation {
    String message() default "不是正確的性別取值范圍";
    String start() default "_";
    Class[] groups() default {};
    Class[] payload() default {};
    @Target({METHOD, FIELD, ANNOTATION_TYPE, CONSTRUCTOR, PARAMETER})
    @Retention(RUNTIME)
    @Documented
    @interface List {
        GenderValidation[] value();
    }
}

@StartWithValidation(message = "Param 'address' must be start with 'Beijing'.", start = "Beijing")
private String address;

package com.example.validation.demo;
import org.springframework.stereotype.Component;
import org.springframework.validation.Errors;
import org.springframework.validation.ValidationUtils;
import org.springframework.validation.Validator;
@Component
public class UserValidator implements Validator {
    @Override
    public boolean supports(Class clazz) {
        return User2.class.equals(clazz);
    }
    @Override
    public void validate(Object target, Errors errors) {
        ValidationUtils.rejectIfEmpty(errors, "name", "name.empty");
        User2 p = (User2) target;
        if (p.getId() == 0) {
            errors.rejectValue("id", "can not be zero");
        }
    }
}

@RestController
public class UserController {
    @Autowired
    UserValidator validator;
    @InitBinder
    public void initBinder(WebDataBinder binder) {
        binder.setValidator(validator);
    }
    @RequestMapping(value = "/user/post", method = RequestMethod.POST)
    public ServiceResponse handValidatePost(@Validated @RequestBody User user) {
        ServiceResponse serviceResponse = new ServiceResponse();
        serviceResponse.setCode(0);
        serviceResponse.setMessage("test");
        return serviceResponse;
    }
}

@RestController
public class UserController {
    ...
    @RequestMapping(value = "/validation/postStudent", method = RequestMethod.POST)
    public ServiceResponse validatePostStudent(@RequestBody User user) {
        // User參數(shù)前面沒有@Validated注解了，User類里面那些注解還是保留著即可。
        HibernateValidatorConfiguration configuration = Validation.byProvider(HibernateValidator.class).configure();
        ValidatorFactory factory = configuration.failFast(true).buildValidatorFactory(); // fastFail
        Validator validator = factory.getValidator();
        Set<constraintviolation> set = validator.validate(user);
        // 根據(jù)set的size，大于0時(shí)，拋異常。由于設(shè)置了failFast，這里set最多就一個(gè)元素
        ServiceResponse serviceResponse = new ServiceResponse();
        serviceResponse.setCode(0);
        serviceResponse.setMessage("test");
        return serviceResponse;
    }
}

// User.java
public class User {
    ... 省略其他屬性
    // 指明在groups={Student.class}時(shí)才需要校驗(yàn)studentId
    @NotNull(groups = {Student.class}, message = "Param 'studentId' must not be null.")
    private Long studentId;
    // 增加Student interface
    public interface Student {
    }
}
// UserController.java，增加了一個(gè)/getStudent接口
@RestController
public class UserController {
    @RequestMapping(value = "/validation/get", method = RequestMethod.GET)
    public ServiceResponse validateGet(@Validated User user) {
        ServiceResponse serviceResponse = new ServiceResponse();
        serviceResponse.setCode(200);
        serviceResponse.setMessage("test");
        return serviceResponse;
    }
    @RequestMapping(value = "/validation/getStudent", method = RequestMethod.GET)
    public ServiceResponse validateGetStudent(@Validated({User.Student.class}) User user) {
        ServiceResponse serviceResponse = new ServiceResponse();
        serviceResponse.setCode(0);
        serviceResponse.setMessage("test");
        return serviceResponse;
    }
}

{
    "code": 51000,
    "message": "Param 'name' must be less than 10 characters."
}

// ServiceExceptionHandler.java
package com.example.validation.demo;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.util.CollectionUtils;
import org.springframework.validation.BindException;
import org.springframework.validation.FieldError;
import org.springframework.web.bind.MethodArgumentNotValidException;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RestControllerAdvice;
import java.util.List;
@RestControllerAdvice
public class ServiceExceptionHandler {
    static final Logger LOG = LoggerFactory.getLogger(ServiceExceptionHandler.class);
    @ExceptionHandler(value = {Exception.class})
    public ServiceResponse handleBindException(Exception ex) {
        LOG.error("{}", ex);
        StringBuilder message = new StringBuilder();
        if (ex instanceof BindException) {
            List fieldErrorList = ((BindException) ex).getFieldErrors();
            if (!CollectionUtils.isEmpty(fieldErrorList)) {
                for (FieldError fieldError : fieldErrorList) {
                    if (fieldError != null && fieldError.getDefaultMessage() != null) {
                        message.append(fieldError.getDefaultMessage()).append(" ");
                    }
                }
            }
        } else if (ex instanceof MethodArgumentNotValidException) {
            List fieldErrorList = ((MethodArgumentNotValidException) ex).getBindingResult().getFieldErrors();
            if (!CollectionUtils.isEmpty(fieldErrorList)) {
                for (FieldError fieldError : fieldErrorList) {
                    if (fieldError != null && fieldError.getDefaultMessage() != null) {
                        message.append(fieldError.getDefaultMessage()).append(" ");
                    }
                }
            }
        }
        // 生成返回結(jié)果
        ServiceResponse errorResult = new ServiceResponse();
        errorResult.setCode(51000); // ErrorCode.PARAM_ERROR = 51000
        errorResult.setMessage(message.toString());
        return errorResult;
    }
}
// User.java，注解傳入指定Message
public class User {
    @NotBlank(message = "Param 'name' can't be blank.")
    @Size(max=10, message = "Param 'name' must be less than 10 characters.")
    private String name;
    ...
}

@NotBlank(message = "Param 'name' can't be blank.")
@Size(max=10,message = "Param 'name' must be less than 10 characters.")
private String name;

{
    "code": 51000,
    "message": "Param 'name' must be less than 10 characters."
}