org.springframework.validation

Class DataBinder

java.lang.Object
- org.springframework.validation.DataBinder

All Implemented Interfaces:
PropertyEditorRegistry, TypeConverter

Direct Known Subclasses:
WebDataBinder
```
public class DataBinder
extends Object
implements PropertyEditorRegistry, TypeConverter      
```
Binder that allows for setting property values onto a target object, including support for validation and binding result analysis. The binding process can be customized through specifying allowed fields, required fields, custom editors, etc.

Note that there are potential security implications in failing to set an array of allowed fields. In the case of HTTP form POST data for example, malicious clients can attempt to subvert an application by supplying values for fields or properties that do not exist on the form. In some cases this could lead to illegal data being set on command objects or their nested objects. For this reason, it is highly recommended to specify the
allowedFields
property on the DataBinder.

The binding results can be examined via the
BindingResult interface, extending the Errors interface: see the getBindingResult() method. Missing fields and property access exceptions will be converted to FieldErrors , collected in the Errors instance, using the following error codes:
- Missing field error: "required"
- Type mismatch error: "typeMismatch"
- Method invocation error: "methodInvocation"
By default, binding errors get resolved through the BindingErrorProcessor strategy, processing for missing fields and property access exceptions: see the setBindingErrorProcessor(org.springframework.validation.BindingErrorProcessor)
method. You can override the default strategy if needed, for example to generate different error codes.

Custom validation errors can be added afterwards. You will typically want to resolve such error codes into proper user-visible error messages; this can be achieved through resolving each error via a
MessageSource , which is able to resolve an ObjectError / FieldError through its MessageSource.getMessage(org.springframework.context.MessageSourceResolvable, java.util.Locale) method. The list of message codes can be customized through the MessageCodesResolver strategy: see the setMessageCodesResolver(org.springframework.validation.MessageCodesResolver) method. DefaultMessageCodesResolver
's javadoc states details on the default resolution rules.

This generic data binder can be used in any kind of environment. It is typically used by Spring web MVC controllers, via the web-specific subclasses
ServletRequestDataBinder and PortletRequestDataBinder .
Author:
Rod Johnson, Juergen Hoeller, Rob Harrop, Stephane Nicoll

at sun.reflect.NativeMethodAccessorImpl.invoke0(NativeMethodAccessorImpl.java:-1)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

at java.lang.reflect.Method.invoke(Method.java:497)

at org.springframework.beans.BeanWrapperImpl$BeanPropertyHandler.setValue(BeanWrapperImpl.java:344)

at org.springframework.beans.AbstractNestablePropertyAccessor.setPropertyValue(AbstractNestablePropertyAccessor.java:452)

at org.springframework.beans.AbstractNestablePropertyAccessor.setPropertyValue(AbstractNestablePropertyAccessor.java:278)

at org.springframework.beans.AbstractPropertyAccessor.setPropertyValues(AbstractPropertyAccessor.java:95)

at org.springframework.validation.DataBinder.applyPropertyValues(DataBinder.java:810)

at org.springframework.validation.DataBinder.doBind(DataBinder.java:706)

at org.springframework.web.bind.WebDataBinder.doBind(WebDataBinder.java:189)

at org.springframework.web.bind.ServletRequestDataBinder.bind(ServletRequestDataBinder.java:106)

at org.springframework.web.servlet.mvc.method.annotation.ServletModelAttributeMethodProcessor.bindRequestParameters(ServletModelAttributeMethodProcessor.java:150)

at org.springframework.web.method.annotation.ModelAttributeMethodProcessor.resolveArgument(ModelAttributeMethodProcessor.java:110)

at org.springframework.web.method.support.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:77)

at org.springframework.web.method.support.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:162)

at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:129)

at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:111)

at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:799)

at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:728)

at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)

at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)

at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)

at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:969)

at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:860)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:622)

at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:845)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)