如何使用spring注解验证@NotNull

public class User implements Serializable {
  /**
   * 主键
   */
  @NotNull(message = "primary is not null",groups = {GroupInterface1.class})
 private Long id;
 
 @Pattern(regexp = "[0123456789]",groups = {GroupInterface1.class,GroupInterface2.class},message = "hava a error Date")
 private Long maxDiscountAmount;
 

 @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
 private Date createTime;

 @Future(message = "expireTime is not less than now",groups = {GroupInterface1.class,GroupInterface2.class})
 @NotNull(message = "expireTime is not null",groups = {GroupInterface1.class,GroupInterface2.class})
 private Date expireTime;

}

import java.util.Date;

import javax.validation.constraints.DecimalMax;
import javax.validation.constraints.DecimalMin;
import javax.validation.constraints.Email;
import javax.validation.constraints.Future;
import javax.validation.constraints.Max;
import javax.validation.constraints.Min;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;

import org.hibernate.validator.constraints.Range;
import org.springframework.format.annotation.DateTimeFormat;

/**** imports ****/
public class ValidatorPojo {

 // 非空判断
 @NotNull(message = "id不能为空")
 private Long id;

 @Future(message = "需要一个将来日期") // 只能是将来的日期
 // @Past //只能去过去的日期
 @DateTimeFormat(pattern = "yyyy-MM-dd") // 日期格式化转换
 @NotNull // 不能为空
 private Date date;

 @NotNull // 不能为空
 @DecimalMin(value = "0.1") // 最小值0.1元
 @DecimalMax(value = "10000.00") // 最大值10000元
 private Double doubleValue = null;

 @Min(value = 1, message = "最小值为1") // 最小值为1
 @Max(value = 88, message = "最大值为88") // 最大值88
 @NotNull // 不能为空
 private Integer integer;

 @Range(min = 1, max = 888, message = "范围为1至888") // 限定范围
 private Long range;

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

 @Size(min = 20, max = 30, message = "字符串长度要求20到30之间。")
 private String size;

 public Long getId() {
 return id;
 }

 public void setId(Long id) {
 this.id = id;
 }

 public Date getDate() {
 return date;
 }

 public void setDate(Date date) {
 this.date = date;
 }

 public Double getDoubleValue() {
 return doubleValue;
 }

 public void setDoubleValue(Double doubleValue) {
 this.doubleValue = doubleValue;
 }

 public Integer getInteger() {
 return integer;
 }

 public void setInteger(Integer integer) {
 this.integer = integer;
 }

 public Long getRange() {
 return range;
 }

 public void setRange(Long range) {
 this.range = range;
 }

 public String getEmail() {
 return email;
 }

 public void setEmail(String email) {
 this.email = email;
 }

 public String getSize() {
 return size;
 }

 public void setSize(String size) {
 this.size = size;
 }

 /**** setter and getter ****/

}

 /***
 * 解析验证参数错误
 * @param vp —— 需要验证的POJO，使用注解@Valid 表示验证
 * @param errors 错误信息，它由Spring MVC通过验证POJO后自动填充
 * @return 错误信息Map
 */
 @RequestMapping(value = "/valid/validate")
 @ResponseBody
 public Map<String, Object> validate(
     @Valid @RequestBody ValidatorPojo vp, Errors errors) {
   Map<String, Object> errMap = new HashMap<>();
   // 获取错误列表
   List<ObjectError> oes = errors.getAllErrors();
   for (ObjectError oe : oes) {
     String key = null;
     String msg = null;
     // 字段错误
     if (oe instanceof FieldError) {
       FieldError fe = (FieldError) oe;
       key = fe.getField();// 获取错误验证字段名
     } else {
       // 非字段错误
       key = oe.getObjectName();// 获取验证对象名称
     }
     // 错误信息
     msg = oe.getDefaultMessage();
     errMap.put(key, msg);
   }
   return errMap;
 }