本篇文章主要介紹了java validation 後台參數驗證的使用詳解，小編覺得挺不錯的，現在分享給大家，也給大家做個參考。一起跟著小編過來看看吧
一、前言
在後台開發過程中，對參數的校驗成為開發環境不可缺少的一個環節。例如參數不能為null，email那麼必須符合email的格式，如果手動進行if判斷或寫正規表示式判斷無意開發效率太慢，在時間、成本、品質的賽局必然會落後。所以把校驗層抽象化是必然的結果，下面說下幾個解決方案。
二、幾個解決方案
1、struts2的valid可以透過設定xml，xml中描述規則和傳回的訊息，這種方式比較麻煩、開發效率低，不推薦
2、validation bean 是基於JSR-303標準開發出來的，使用註解方式實現，及其方便，但是這只是一個接口，沒有具體實現. Hibernate Validator是一個hibernate獨立的包，可以直接引用，他實現了validation bean同時有做了擴展，比較強大，實現圖如下：
三、bean validation 框架驗證介紹
bean validation 套件放在maven上維護,最新套件的座標如下：<dependency> <groupId>javax.validation</groupId> <artifactId>validation-api</artifactId> <version>1.1.0.Final</version> </dependency>
# 
package com.shishang;
import javax.validation.constraints.*;
import java.io.Serializable;
import java.math.BigDecimal;
import java.util.Date;
public class Student implements Serializable {
@NotNull(message = "名字不能为空")
private String name;
@Size(min = 6,max = 30,message = "地址应该在6-30字符之间")
private String address;
@DecimalMax(value = "100.00",message = "体重有些超标哦")
@DecimalMin(value = "60.00",message = "多吃点饭吧")
private BigDecimal weight;
private String friendName;
@AssertTrue
private Boolean isHaveFriend(){
return friendName != null?true:false;
}
@Future(message = "生日必须在当前实践之前")
private Date birthday;
@Pattern(regexp = "^(.+)@(.+)$",message = "邮箱的格式不合法")
private String email;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public BigDecimal getWeight() {
return weight;
}
public void setWeight(BigDecimal weight) {
this.weight = weight;
}
public String getFriendName() {
return friendName;
}
public void setFriendName(String friendName) {
this.friendName = friendName;
}
public Date getBirthday() {
return birthday;
}
public void setBirthday(Date birthday) {
this.birthday = birthday;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
}package com.use;
import javax.validation.ConstraintViolation;
import javax.validation.Validation;
import javax.validation.Validator;
import javax.validation.ValidatorFactory;
import java.io.Serializable;
import java.math.BigDecimal;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.Set;
public class StudentTest implements Serializable {
public static void main(String[] args) {
Student xiaoming = getBean();
List<String> validate = validate(xiaoming);
validate.forEach(row -> {
System.out.println(row.toString());
});
}
private static Student getBean() {
Student bean = new Student();
bean.setName(null);
bean.setAddress("北京");
bean.setBirthday(new Date());
bean.setFriendName(null);
bean.setWeight(new BigDecimal(30));
bean.setEmail("xiaogangfan163.com");
return bean;
}
private static ValidatorFactory factory = Validation.buildDefaultValidatorFactory();
public static <T> List<String> validate(T t) {
Validator validator = factory.getValidator();
Set<ConstraintViolation<T>> constraintViolations = validator.validate(t);
List<String> messageList = new ArrayList<>();
for (ConstraintViolation<T> constraintViolation : constraintViolations) {
messageList.add(constraintViolation.getMessage());
}
return messageList;
}
}四、自訂bean validation 註解驗證有時框架自帶的沒法滿足我們的需求，這時就需要自己動手豐衣足食了，恩恩，這個不難，下面說下。
這個範例驗證字串是大寫還是小寫約束標註，程式碼如下:
1、枚舉型別CaseMode, 來表示大寫或小寫模式
package com.defineconstrain;
/**
* created by xiaogangfan
* on 16/10/25.
*/
public enum CaseMode {
UPPER,
LOWER;
}#
package com.defineconstrain;
/**
* created by xiaogangfan
* on 16/10/25.
*/
import static java.lang.annotation.ElementType.*;
import static java.lang.annotation.RetentionPolicy.*;
import java.lang.annotation.Documented;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
import javax.validation.Constraint;
import javax.validation.Payload;
@Target( { METHOD, FIELD, ANNOTATION_TYPE })
@Retention(RUNTIME)
@Constraint(validatedBy = CheckCaseValidator.class)
@Documented
public @interface CheckCase {
String message() default "{com.mycompany.constraints.checkcase}";
Class<?>[] groups() default {};
Class<? extends Payload>[] payload() default {};
CaseMode value();
}#
package com.defineconstrain;
/**
* created by xiaogangfan
* on 16/10/25.
*/
import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;
public class CheckCaseValidator implements ConstraintValidator<CheckCase, String> {
private CaseMode caseMode;
public void initialize(CheckCase constraintAnnotation) {
this.caseMode = constraintAnnotation.value();
}
public boolean isValid(String object, ConstraintValidatorContext constraintContext) {
if (object == null)
return true;
if (caseMode == CaseMode.UPPER)
return object.equals(object.toUpperCase());
else
return object.equals(object.toLowerCase());
}
}#
@CheckCase(value = CaseMode.LOWER,message = "名字的拼音需要小写") private String spellName;
bean.setSpellName("XIAOGANGFAN");以上是Java中有關validation後台參數驗證的使用詳解的詳細內容。更多資訊請關注PHP中文網其他相關文章！
