Spring MVC binding
I have the following command object:
public class User {
private Department department;
private String firstName;
private String lastName;
private String login;
private String password;
...
}
which should be rendered at jsp page:
<form:input path="lastName" />
<form:input path="department.name"/>
<form:input path="department.description"/>
So when I submit with empty department.name and department.description the Spring auto-instantiate ob开发者_如何学Cject Department with empty properties. (See https://jira.springframework.org/browse/SPR-6032 I would keep autoGrowNestedPaths=true)
What is need to do for getting back User object where Department object=null?
What is need to do for getting back User object where Department object=null?
If you are looking for controller specific solution, then find all the empty nested params and set these params as disallowed fields.
@InitBinder(value="user")
public void bind(WebDataBinder dataBinder, WebRequest webRequest) {
List<String> emptyParams = new ArrayList<String>();
Iterator<String> itr = webRequest.getParameterNames();
while(itr.hasNext()) {
String name = itr.next();
if(name.startsWith("department.")) {
Object value = webRequest.getParameter(name);
if("".equals(value)) {
emptyParams.add(name);
}
}
}
if(!emptyParams.isEmpty()) {
dataBinder.setDisallowedFields(emptyParams.toArray(new String[emptyParams.size()]));
}
}
If you are looking for a generic solution create a custom data binder and remove all nested params that are empty.
public class CustomDataBinder extends ServletRequestDataBinder {
@Override
protected void doBind(MutablePropertyValues mpvs) {
PropertyValue[] pvArray = mpvs.getPropertyValues();
for (PropertyValue pv : pvArray) {
boolean nestedProperty = PropertyAccessorUtils.isNestedOrIndexedProperty(pv.getName());
if(nestedProperty && "".equals(pv.getValue())) {
mpvs.removePropertyValue(pv);
}
}
super.doBind(mpvs);
}
}
And to use CustomDataBinder you must have custom HandlerAdapter.
public class StandardAnnotationMethodHandlerAdapter extends AnnotationMethodHandlerAdapter {
@Override
protected ServletRequestDataBinder createBinder(HttpServletRequest request, Object target, String objectName) throws Exception {
CustomDataBinder dataBinder = new CustomDataBinder (target, objectName);
return dataBinder;
}
}
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