org.springframework.web.bind
Class ServletRequestDataBinder

java.lang.Object
  org.springframework.validation.DataBinder
      org.springframework.web.bind.WebDataBinder
          org.springframework.web.bind.ServletRequestDataBinder

All Implemented Interfaces:

PropertyEditorRegistry

public class ServletRequestDataBinder
extends WebDataBinder

Special DataBinder to perform data binding from servlet request parameters to JavaBeans, including support for multipart files.

See the DataBinder/WebDataBinder superclasses for customization options, which include specifying allowed/required fields, and registering custom property editors.

Used by Spring web MVC's BaseCommandController and MultiActionController. Note that BaseCommandController and its subclasses allow for easy customization of the binder instances that they use through overriding initBinder.

Can also be used for manual data binding in custom web controllers: for example, in a plain Controller implementation or in a MultiActionController handler method. Simply instantiate a ServletRequestDataBinder for each binding process, and invoke bind with the current ServletRequest as argument:

 MyBean myBean = new MyBean();
 // apply binder to custom target object
 ServletRequestDataBinder binder = new ServletRequestDataBinder(myBean);
 // register custom editors, if desired
 binder.registerCustomEditor(...);
 // trigger actual binding of request parameters
 binder.bind(request);
 // optionally evaluate binding errors
 Errors errors = binder.getErrors();
 ...

Author:

Rod Johnson, Juergen Hoeller

See Also:

bind(javax.servlet.ServletRequest), DataBinder.registerCustomEditor(java.lang.Class, java.beans.PropertyEditor), DataBinder.setAllowedFields(java.lang.String[]), DataBinder.setRequiredFields(java.lang.String[]), WebDataBinder.setFieldMarkerPrefix(java.lang.String), BaseCommandController.initBinder(javax.servlet.http.HttpServletRequest, org.springframework.web.bind.ServletRequestDataBinder), MultiActionController.initBinder(javax.servlet.ServletRequest, org.springframework.web.bind.ServletRequestDataBinder)

Field Summary

Fields inherited from class org.springframework.web.bind.WebDataBinder

DEFAULT_FIELD_MARKER_PREFIX

Fields inherited from class org.springframework.validation.DataBinder

DEFAULT_OBJECT_NAME, logger

Constructor Summary

ServletRequestDataBinder(Object target)
Create a new ServletRequestDataBinder instance, with default object name.

ServletRequestDataBinder(Object target, String objectName)
Create a new ServletRequestDataBinder instance.

Method Summary

void	bind(ServletRequest request) Bind the parameters of the given request to this binder's target, also binding multipart files in case of a multipart request.
protected void	checkMultipartFiles(ServletRequest request, MutablePropertyValues mpvs) Check the multipart files contained in the given request, if any (in case of a multipart request).
void	closeNoCatch() Treats errors as fatal.
boolean	isBindEmptyMultipartFiles() Return whether to bind empty MultipartFile parameters.
void	setBindEmptyMultipartFiles(boolean bindEmptyMultipartFiles) Set whether to bind empty MultipartFile parameters.

Methods inherited from class org.springframework.web.bind.WebDataBinder

checkFieldMarkers, doBind, getEmptyValue, getFieldMarkerPrefix, setFieldMarkerPrefix

Methods inherited from class org.springframework.validation.DataBinder

applyPropertyValues, bind, checkAllowedFields, checkRequiredFields, close, createErrors, findCustomEditor, getAllowedFields, getBeanWrapper, getBindingErrorProcessor, getErrors, getObjectName, getRequiredFields, getTarget, isAllowed, isIgnoreUnknownFields, registerCustomEditor, registerCustomEditor, setAllowedFields, setBindingErrorProcessor, setExtractOldValueForEditor, setIgnoreUnknownFields, setMessageCodesResolver, setRequiredFields

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ServletRequestDataBinder

public ServletRequestDataBinder(Object target)

Create a new ServletRequestDataBinder instance, with default object name.

Parameters:

target - target object to bind onto

See Also:

DataBinder.DEFAULT_OBJECT_NAME

ServletRequestDataBinder

public ServletRequestDataBinder(Object target,
                                String objectName)

Create a new ServletRequestDataBinder instance.

Parameters:

target - target object to bind onto

objectName - objectName of the target object

Method Detail

setBindEmptyMultipartFiles

public void setBindEmptyMultipartFiles(boolean bindEmptyMultipartFiles)

Set whether to bind empty MultipartFile parameters. Default is "true".

Turn this off if you want to keep an already bound MultipartFile when the user resubmits the form without choosing a different file. Else, the already bound MultipartFile will be replaced by an empty MultipartFile holder.

isBindEmptyMultipartFiles

public boolean isBindEmptyMultipartFiles()

Return whether to bind empty MultipartFile parameters.

bind

public void bind(ServletRequest request)

Bind the parameters of the given request to this binder's target, also binding multipart files in case of a multipart request.

This call can create field errors, representing basic binding errors like a required field (code "required"), or type mismatch between value and bean property (code "typeMismatch").

Multipart files are bound via their parameter name, just like normal HTTP parameters: i.e. "uploadedFile" to an "uploadedFile" bean property, invoking a "setUploadedFile" setter method.

The type of the target property for a multipart file can be MultipartFile, byte[], or String. The latter two receive the contents of the uploaded file; all metadata like original file name, content type, etc are lost in those cases.

Parameters:

request - request with parameters to bind (can be multipart)

See Also:

MultipartHttpServletRequest, MultipartFile, checkMultipartFiles(javax.servlet.ServletRequest, org.springframework.beans.MutablePropertyValues), DataBinder.bind(org.springframework.beans.PropertyValues)

checkMultipartFiles

protected void checkMultipartFiles(ServletRequest request,
                                   MutablePropertyValues mpvs)

Check the multipart files contained in the given request, if any (in case of a multipart request).

Multipart files will only be added to the property values if they are not empty or if we're configured to bind empty multipart files too.

Parameters:

request - current request (can be multipart)

mpvs - the property values to be bound (can be modified)

See Also:

MultipartHttpServletRequest, MultipartFile, isBindEmptyMultipartFiles()

closeNoCatch

public void closeNoCatch()
                  throws ServletRequestBindingException

Treats errors as fatal. Use this method only if it's an error if the input isn't valid. This might be appropriate if all input is from dropdowns, for example.

Throws:

ServletRequestBindingException - subclass of ServletException on any binding problem