Spring form submit validation for foreign key - forms

Question

My project is a spring mvc project.In my project i have a domain Technology which has foreign key reference.When i validating on form submit it threw error....For view part(jsp),i using form:select for viewing department in technology.
How can i validate a foreign reference?????
i tried below code
domain
#Entity
#Table(name = "technology")
public class Technology {
private int id;
#NotEmpty
private String name;
#NotEmpty
private Department department;
private Date createdDate;
private boolean isDelete;
}
message.properties
NotEmpty.technology.department=Required!
Technology.jsp
<form:form method="post" action="add-technology"
commandName="technology" id="technologyForm">
<label>Technology Name</label>
<form:input path="name" /><form:errors path="name" class="error"></form:errors>
<br />
<label>Department</label>
<form:select path="department.id">
<form:option value="0" label="Select" />
<form:options items="${departments}" itemValue="id" itemLabel="name" />
</form:select><form:errors path="department" class="error"></form:errors>
<%-- <form:select path="department.id" items="${departments}" /> --%>
<input type="submit" class="btn btn-primary"/>
</form:form>
controller
#RequestMapping(value = "/add-technology")
public String addTechnology(
#ModelAttribute(value = "technology")#Valid Technology technology,
BindingResult result) {
if(result.hasErrors()){
return "/secure/admin/technology";
}
java.util.Date utilDate = new java.util.Date();
Date sqlDate = new Date(utilDate.getTime());
technology.setCreatedDate(sqlDate);
technologyService.saveTechnology(technology);
return "redirect:/technologies";
}
ERROR
org.springframework.web.util.NestedServletException: Request processing failed; nested exception is javax.validation.UnexpectedTypeException: No validator could be found for type: com.company.product.domain.Department
How can i resolve this problem???

Answer 1

Here you have to implement validator for Technology object
class TechnologyValidator extends Validator {
public boolean supports(Class<?> cls) {
return Technology .class.equals(cls);
}
public void validate(Object target, Errors errors) {
super.validate(target, errors);
Technology tecObj= (Technology ) target;
//here i am assuming Technology name is REQUIRED and
//NotEmpty.technology.name is in message.properties
ValidationUtils.rejectIfEmptyOrWhitespace(errors,"name",
"NotEmpty.technology.name");
Department dept = tecObj.getDepartment();
//as from from your are binding department ID
if (dept==null || dept.getId()==null || dept.getId()==0L ) {
errors.rejectValue("department.id", "NotEmpty.technology.department");
}
}
}
And create bean of this class in Spring-context
#Autowired
TechnologyValidator techValid;
And call this validator in your controller like
#RequestMapping(value = "/add-technology")
public String addTechnology(
#ModelAttribute(value = "technology") Technology technology,
BindingResult result) {
//call validator
techValid.validate(technology, result);
if(result.hasErrors()){
return "/secure/admin/technology";
}
java.util.Date utilDate = new java.util.Date();
Date sqlDate = new Date(utilDate.getTime());
technology.setCreatedDate(sqlDate);
technologyService.saveTechnology(technology);
return "redirect:/technologies";
}