怎么在springMVC中引入Validation
怎么在springMVC中引入Validation？针对这个问题，这篇文章详细介绍了相对应的分析和解答，希望可以帮助更多想解决这个问题的小伙伴找到更简单易行的方法。
基本配置
pom引入maven依赖
<!--validationbegin--> <dependency> <groupId>javax.validation</groupId> <artifactId>validation-api</artifactId> <version>1.1.0.Final</version> </dependency> <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-validator</artifactId> <version>5.4.0.Final</version> </dependency> <!--validationend-->
增加validation配置
在spring-mvc-servlet.xml中增加如下配置:
<mvc:annotation-drivenvalidator="validator"> <beanid="validator"class="org.springframework.validation.beanvalidation.LocalValidatorFactoryBean"> <propertyname="providerClass"value="org.hibernate.validator.HibernateValidator"/> <propertyname="validationMessageSource"ref="messageSource"/> </bean> //messageSource为i18n资源管理bean，见applicationContext.xml配置
自定义exceptionHandler
个性化处理validation错误信息,返回给调用方的信息更加友好， 在applicationContext.xml中增加如下配置:
<!--加载i18n消息资源文件--> <beanid="messageSource"class="org.springframework.context.support.ResourceBundleMessageSource"> <propertyname="basenames"> <list> <value>errormsg</value> <value>validation_error</value> </list> </property> </bean> <beanid="validationExceptionResolver"class="com.*.exception.ValidationExceptionResovler"/>
在项目类路径上增加：validation_error_zh_CN.properties资源文件：
#theerrormsgforinputvalidation
#common
field.can.not.be.null={field}不能为空
field.can.not.be.empty={field}不能为空或者空字符串
field.must.be.greater.than.min={field}不能小于{value}
field.must.be.letter.than.max={field}不能大于{value}ValidationExceptionResovler实现：
ValidationExceptionResovler.java
@Slf4j
publicclassValidationExceptionResovlerextendsAbstractHandlerExceptionResolver{
publicValidationExceptionResovler(){
//设置order，在DefaultHandlerExceptionResolver之前执行
this.setOrder(0);
}
/**
*Handlethecasewhereanargumentannotatedwith{@code@Valid}suchas
*an{@link}or{@link}argumentfailsvalidation.
*<p>
*自定义ValidationException异常处理器
*获取到具体的validation错误信息，并组装CommonResponse，返回给调用方。
*
*@paramrequestcurrentHTTPrequest
*@paramresponsecurrentHTTPresponse
*@paramhandlertheexecutedhandler
*@returnanemptyModelAndViewindicatingtheexceptionwashandled
*@throwsIOExceptionpotentiallythrownfromresponse.sendError()
*/
@ResponseBody
protectedModelAndViewhandleMethodArgumentNotValidException(BindingResultbindingResult,
HttpServletRequestrequest,
HttpServletResponseresponse,
Objecthandler)
throwsIOException{
List<ObjectError>errors=bindingResult.getAllErrors();
StringBuffererrmsgBF=newStringBuffer();
for(ObjectErrorerror:errors){
Stringmassage=error.getDefaultMessage();
errmsgBF.append(massage);
errmsgBF.append("||");
}
StringerrmsgString=errmsgBF.toString();
errmsgString=errmsgString.length()>2?errmsgString.substring(0,errmsgString.length()-2):errmsgString;
log.error("Validationfailed!{}",errmsgString);
Map<String,Object>map=newTreeMap<String,Object>();
map.put("success",false);
map.put("errorCode","9999");
map.put("errorMsg",errmsgString);
ModelAndViewmav=newModelAndView();
MappingJackson2JsonViewview=newMappingJackson2JsonView();
view.setAttributesMap(map);
mav.setView(view);
returnmav;
}
@Override
protectedModelAndViewdoResolveException(HttpServletRequestrequest,
HttpServletResponseresponse,Objecthandler,
Exceptionex){
BindingResultbindingResult=null;
if(exinstanceofMethodArgumentNotValidException){
bindingResult=((MethodArgumentNotValidException)ex).getBindingResult();
}elseif(exinstanceofBindException){
bindingResult=((BindException)ex).getBindingResult();
}else{
//otherexception,ignore
}
if(bindingResult!=null){
try{
returnhandleMethodArgumentNotValidException(bindingResult,request,response,handler);
}catch(IOExceptione){
log.error("doResolveException:",e);
}
}
returnnull;
}
}在controller中增加@Valid
@RequestMapping("/buy")
@ResponseBody
publicBaseResponsebuy(@RequestBody@ValidBuyFlowerRequestrequest)throwsException{
//......
}在request bean上为需要validation的属性增加validation注解
@Setter
@Getter
publicclassBuyFlowerRequest{
@NotEmpty(message="{name.can.not.be.null}")
privateStringname;
}二级对象的validation
上面的写法，只能对BuyFlowerRequest在基本类型属性上做校验,但是没有办法对对象属性的属性进行validation,如果需要对二级对象的属性进行validation,则需要在二级对象及二级对象属性上同时添加@Valid 和 具体的validation注解.
如下写法:
@Setter
@Getter
publicclassBuyFlowerRequest{
@NotEmpty(field="花名")
privateStringname;
@Min(field="价格",value=1)
privateintprice;
@NotNull
privateList<PayType>payTypeList;
}
@Setter
@Getter
publicclassPayType{
@Valid
@Min(value=1)
privateintpayType;
@Valid
@Min(value=1)
privateintpayAmount;
}进一步减少编码量
为了减少编码工作量,通过自定义Validation注解,尝试将validation作用的filed名称传递到 错误信息的资源文件中,从而避免为每个域编写不同的message模版.
下面以重写的@NotNull为例讲解:
1、定义Validation注解,注意相比原生注解增加了field(),用于传递被validated的filed名字
NotNull.java
@Target({ElementType.METHOD,ElementType.FIELD,ElementType.ANNOTATION_TYPE,ElementType.CONSTRUCTOR,ElementType.PARAMETER})
@Constraint(validatedBy={NotNullValidator.class})
@Retention(RetentionPolicy.RUNTIME)
public@interfaceNotNull{
Stringfield()default"";
Stringmessage()default"{field.can.not.be.null}";
Class<?>[]groups()default{};
Class<?extendsPayload>[]payload()default{};
}2、定义Validator,所有的Validator均实现ConstraintValidator接口:
NotNullValidator.java
publicclassNotNullValidatorimplementsConstraintValidator<NotNull,Object>{
@Override
publicvoidinitialize(NotNullannotation){
}
@Override
publicbooleanisValid(Objectstr,ConstraintValidatorContextconstraintValidatorContext){
returnstr!=null;
}
}3、在filed上加入Validation注解,注意指定filed值,message如果没有个性化需求，可以不用指明，validation组件会自行填充default message。
BuyFlowerRequest.java
@Setter
@Getter
publicclassBuyFlowerRequest{
@NotEmpty(field="花名")
privateStringname;
@Min(field="价格",value=1)
privateintprice;
}注：@NotNull注解已经支持对list的特殊校验，对于List类型节点，如果list==null || list.size() == 0都会返回false，validation失败。目前已按照此思路自定义实现了@NotNull、@NotEmpty、@Min、@Max注解,在goods工程中可以找到.
支持GET请求
上面的示例都是POST请求，@RequestBody可以 resolve POST请求，但是不支持GET请求，阅读spring的文档和源码，发现@ModelAttribute可以将GET请求resolve成Bean，且支持Validation。具体可以翻阅spring源码：ModelAttributeMethodProcessor.resolveArgument()方法。
使用示例：
@RequestMapping(value="/buy",method=RequestMethod.GET)
@ResponseBody
publicBaseResponsedetail(@Valid@ModelAttributeDetailFlowerRequestrequest)throwsException{
DetailFlowerResponseresponse=newDetailFlowerResponse();
response.setName(request.getName());
returnResultFactory.success(response,BaseResponse.class);
}TODO
1、根据业务场景扩展validation,如:日期格式、金额等
2、支持多个field关系校验的validation
附：spring validation实现关键代码
@RequestBody
实现类：RequestResponseBodyMethodProcessor.java
publicObjectresolveArgument(MethodParameterparameter,ModelAndViewContainermavContainer,NativeWebRequestwebRequest,WebDataBinderFactorybinderFactory)throwsException{
Objectarg=this.readWithMessageConverters(webRequest,parameter,parameter.getGenericParameterType());
Stringname=Conventions.getVariableNameForParameter(parameter);
WebDataBinderbinder=binderFactory.createBinder(webRequest,arg,name);
if(arg!=null){
this.validateIfApplicable(binder,parameter);
if(binder.getBindingResult().hasErrors()&&this.isBindExceptionRequired(binder,parameter)){
thrownewMethodArgumentNotValidException(parameter,binder.getBindingResult());
}
}
mavContainer.addAttribute(BindingResult.MODEL_KEY_PREFIX+name,binder.getBindingResult());
returnarg;
}@ModelAttibute
实现类：ModelAttributeMethodProcessor.java
publicfinalObjectresolveArgument(MethodParameterparameter,ModelAndViewContainermavContainer,NativeWebRequestwebRequest,WebDataBinderFactorybinderFactory)throwsException{
Stringname=ModelFactory.getNameForParameter(parameter);
Objectattribute=mavContainer.containsAttribute(name)?mavContainer.getModel().get(name):this.createAttribute(name,parameter,binderFactory,webRequest);
if(!mavContainer.isBindingDisabled(name)){
ModelAttributeann=(ModelAttribute)parameter.getParameterAnnotation(ModelAttribute.class);
if(ann!=null&&!ann.binding()){
mavContainer.setBindingDisabled(name);
}
}
WebDataBinderbinder=binderFactory.createBinder(webRequest,attribute,name);
if(binder.getTarget()!=null){
if(!mavContainer.isBindingDisabled(name)){
this.bindRequestParameters(binder,webRequest);
}
this.validateIfApplicable(binder,parameter);
if(binder.getBindingResult().hasErrors()&&this.isBindExceptionRequired(binder,parameter)){
thrownewBindException(binder.getBindingResult());
}
}
Map<String,Object>bindingResultModel=binder.getBindingResult().getModel();
mavContainer.removeAttributes(bindingResultModel);
mavContainer.addAllAttributes(bindingResultModel);
returnbinder.convertIfNecessary(binder.getTarget(),parameter.getParameterType(),parameter);
}关于怎么在springMVC中引入Validation问题的解答就分享到这里了，希望以上内容可以对大家有一定的帮助，如果你还有很多疑惑没有解开，可以关注恰卡编程网行业资讯频道了解更多相关知识。
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