<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>springboot-demo</artifactId>
        <groupId>com.et</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
    <artifactId>validtion</artifactId>
    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-autoconfigure</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
        <dependency>
            <groupId>cn.hutool</groupId>
            <artifactId>hutool-all</artifactId>
            <version>5.8.16</version>
        </dependency>
    </dependencies>
</project>

package com.et.validation.controller;
import cn.hutool.json.JSON;
import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import com.et.validation.entity.UserInfoReq;
import com.fasterxml.jackson.databind.util.JSONPObject;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.HashMap;
import java.util.Map;
@RestController
public class HelloWorldController {
    @RequestMapping("/hello")
    public Map<String, Object> showHelloWorld(@RequestBody @Validated UserInfoReq req){
        Map<String, Object> map = new HashMap<>();
        map.put("msg", JSONUtil.toJsonStr(req));
        return map;
    }
}

package com.et.validation.entity;
import com.et.validation.validate.IpAddress;
import lombok.Data;
import lombok.ToString;
import javax.validation.constraints.*;
@Data
@ToString
public class UserInfoReq {
    @NotNull(message = "id不能為null")
    private Long id;
    @NotBlank(message = "username不能為空")
    private String username;
    @NotNull(message = "age不能為null")
    @Min(value = 1, message = "年齡不符合要求")
    @Max(value = 200, message = "年齡不符合要求")
    private Integer age;
    @Email(message = "郵箱不符合規(guī)范")
    private String email;
    @IpAddress(message = "ip不符合規(guī)范")
    //@Pattern(regexp = "^[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}$") 
    private String ip;
}

package com.et.validation.error;
import org.springframework.http.HttpStatus;
import org.springframework.validation.FieldError;
import org.springframework.web.bind.MethodArgumentNotValidException;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.ResponseStatus;
import javax.validation.ConstraintViolation;
import javax.validation.ConstraintViolationException;
@ControllerAdvice
class ErrorHandlingControllerAdvice {
  @ExceptionHandler(ConstraintViolationException.class)
  @ResponseStatus(HttpStatus.BAD_REQUEST)
  @ResponseBody
  ValidationErrorResponse onConstraintValidationException(
      ConstraintViolationException e) {
    ValidationErrorResponse error = new ValidationErrorResponse();
    for (ConstraintViolation violation : e.getConstraintViolations()) {
      error.getViolations().add(
        new Violation(violation.getPropertyPath().toString(), violation.getMessage()));
    }
    return error;
  }
  @ExceptionHandler(MethodArgumentNotValidException.class)
  @ResponseStatus(HttpStatus.BAD_REQUEST)
  @ResponseBody
  ValidationErrorResponse onMethodArgumentNotValidException(
      MethodArgumentNotValidException e) {
    ValidationErrorResponse error = new ValidationErrorResponse();
    for (FieldError fieldError : e.getBindingResult().getFieldErrors()) {
      error.getViolations().add(
        new Violation(fieldError.getField(), fieldError.getDefaultMessage()));
    }
    return error;
  }
}

package com.et.validation.error;
import lombok.Data;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;
@Data
public class ValidationErrorResponse implements Serializable {
  private List<Violation> violations = new ArrayList<>();
}

package com.et.validation.error;
import lombok.Data;
import java.io.Serializable;
@Data
public class Violation implements Serializable {
  private final String fieldName;
  private final String message;
  public Violation(String fieldName, String message) {
    this.fieldName = fieldName;
    this.message = message;
  }
}

package com.et.validation.validate;
import javax.validation.Constraint;
import javax.validation.Payload;
import java.lang.annotation.Documented;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.RetentionPolicy.RUNTIME;
@Target({ FIELD })
@Retention(RUNTIME)
@Constraint(validatedBy = IpAddressValidator.class)
@Documented
public @interface IpAddress {
  String message() default "{IpAddress.invalid}";
  Class<?>[] groups() default { };
  Class<? extends Payload>[] payload() default { };
}

package com.et.validation.validate;
import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
class IpAddressValidator implements ConstraintValidator<IpAddress, String> {
  @Override
  public boolean isValid(String value, ConstraintValidatorContext context) {
    Pattern pattern =
      Pattern.compile("^([0-9]{1,3})\\.([0-9]{1,3})\\.([0-9]{1,3})\\.([0-9]{1,3})$");
    Matcher matcher = pattern.matcher(value);
    try {
      if (!matcher.matches()) {
        return false;
      } else {
        for (int i = 1; i <= 4; i++) {
          int octet = Integer.valueOf(matcher.group(i));
          if (octet > 255) {
            return false;
          }
        }
        return true;
      }
    } catch (Exception e) {
      return false;
    }
  }
}