利用javax.validation实现对bean属性校验
1.使用场景介绍
controller层对传入的bean的属性进行非空、属性长度等合法性的校验。
传统的方式是我们要自己写if…else…去判断,比较麻烦。
2.实现效果
3.代码介绍
代码结构:
pom.xml
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-validation</artifactId>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
3.1 工具类
/**
* @Description: 校验结果
* @Author laoxu
* @Date 2020/5/27 23:30
**/
@Data
public class ValidationResult {
// 校验结果是否有错
private boolean hasErrors;
// 校验错误信息
private Map<String, String> errorMsg;
}
public class ValidationUtils {
private static Validator validator = Validation.buildDefaultValidatorFactory().getValidator();
public static <T> ValidationResult validateEntity(T obj) {
ValidationResult result = new ValidationResult();
Set<ConstraintViolation<T>> set = validator.validate(obj, Default.class);
// if( CollectionUtils.isNotEmpty(set) ){
if (set != null && set.size() != 0) {
result.setHasErrors(true);
Map<String, String> errorMsg = new HashMap<String, String>();
for (ConstraintViolation<T> cv : set) {
errorMsg.put(cv.getPropertyPath().toString(), cv.getMessage());
}
result.setErrorMsg(errorMsg);
}
return result;
}
public static <T> ValidationResult validateProperty(T obj, String propertyName) {
ValidationResult result = new ValidationResult();
Set<ConstraintViolation<T>> set = validator.validateProperty(obj, propertyName, Default.class);
if (set != null && set.size() != 0) {
result.setHasErrors(true);
Map<String, String> errorMsg = new HashMap<String, String>();
for (ConstraintViolation<T> cv : set) {
errorMsg.put(propertyName, cv.getMessage());
}
result.setErrorMsg(errorMsg);
}
return result;
}
/**
* bean整体校验,把所有违规信息,输出String。
*/
public static String validate(Object o, Class<?>... groups){
Set<ConstraintViolation<Object>> resultSet=validator.validate(o, groups);
if(resultSet == null || resultSet.size() ==0){
return null;
}
StringBuilder sb = new StringBuilder();
for(ConstraintViolation<Object> constraintViolation : resultSet) {
sb.append(constraintViolation.getMessageTemplate()).append(",");
}
return sb.substring(0,sb.length()-1);
}
}
3.2 模型类
@Data
public class Student {
@Length(max=20,message="姓名长度不能大于20")
@NotEmpty(message="姓名不能为空")
private String name;
@Range(min = 0, max = 1, message = "性别只能输入只能输入0或1")
private Integer gender;
private Integer age;
@Email
private String email;
@NotBlank(message = "身份证号不能为空")
@PhoneNumber
private String phone;
}
3.3 注解类
/**
* 自定义验证
*/
@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.PARAMETER, ElementType.FIELD})
// 指定真正实现校验规则的类
@Constraint(validatedBy = PhoneValidator.class)
public @interface PhoneNumber {
String message() default "手机号不合法";
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
}
3.4 实现类
public class PhoneValidator implements ConstraintValidator<PhoneNumber,String> {
@Override
public boolean isValid(String s, ConstraintValidatorContext constraintValidatorContext)
{
return s.length()==11;
}
}
3.5 控制器
@RestController
@RequestMapping("/api/student")
public class StudentController {
private static final Logger log = LoggerFactory.getLogger(StudentController.class);
@PostMapping("add")
public String add(@RequestBody Student student){
ValidationResult validationResult = ValidationUtils.validateEntity(student);
if(validationResult.isHasErrors()){
return validationResult.getErrorMsg().toString();
}
return "添加成功";
}
}