The errors tag

The errors tag

In this section, you will learn about the errors tag of the Spring form tag library.

This tag provide errors of field in HTML <span> tag. This gives access to the errors developed in your controller or that were developed by any validators of your controller.

Example

Consider the following form :

<form:form>
	<table>
		<tr>
		<td>First Name:</td>
		<td><form:input path="firstName" /></td>
		</tr>
		<tr>
		<td>Last Name:</td>
		<td><form:input path="lastName" /></td>
		</tr>
		<tr>
		<td colspan="2">
		<input type="submit" value="Save Changes" />
		</td>
		</tr>
	</table>
</form:form>

Consider a situation where we want to display all the error messages for the the firstName and lastName fields after form submission. Given below a validator EmployeeValidator for Employee class :

public class EmployeeValidator implements Validator {
	public boolean supports(Class examinee) {
		return Employee.class.isAssignableFrom(examinee);
	}
	
	public void validate(Object obj, Errors errors) {
		ValidationUtils.rejectIfEmptyOrWhitespace(errors, "firstName", "required", "Field is required.");
		ValidationUtils.rejectIfEmptyOrWhitespace(errors, "lastName", "required", "Field is required.");
	}
}

The form.jsp would be :

<form:form>
	<table>
		<tr>
			<td>First Name:</td>
			<td><form:input path="firstName" /></td>
			<%-- For displaying errors for firstName --%>
			<td><form:errors path="firstName" /></td>
		</tr>
		
		<tr>
			<td>Last Name:</td>
			<td><form:input path="lastName" /></td>
			<%-- For displaying errors for lastName --%>
			<td><form:errors path="lastName" /></td>
		</tr>
		<tr>
			<td colspan="3">
			<input type="submit" value="Submit" />
			</td>
		</tr>
	</table>
</form:form>

When you submit the value without filling the firstName and the lastName or leave blank, the HTML form would look something like below :

<form method="POST">
	<table>
		<tr>
		<td>First Name:</td>
		<td><input name="firstName" type="text" value=""/></td>
		<%-- For displaying errors for firstName --%>
		<td><span name="firstName.errors">Field is required.</span></td>
		</tr>
		
		<tr>
		<td>Last Name:</td>
		<td><input name="lastName" type="text" value=""/></td>
		<%-- For displaying errors for lastName --%>
		<td><span name="lastName.errors">Field is required.</span></td>
		</tr>
		<tr>
		<td colspan="3">
		<input type="submit" value="Submit" />
		</td>
		</tr>
	</table>
</form>

Wildcard functionalities of the errors tag

The wildcard functionalities of the errors tag is given below :

• path="*" : For displaying all the errors of the of a given page.
• path="lastName": It will show all the errors associated with the lastName field.
• If path is omitted: Only object errors are displayed.

Example

Given below an example for showing errors list at the page top and  field related errors are showing next to the fields :

<form:form>
		<form:errors path="*" cssClass="errorBlock" />
		<table>
			<tr>
			<td>First Name:</td>
			<td><form:input path="firstName" /></td>
			<td><form:errors path="firstName" /></td>
			</tr>
			<tr>
			<td>Last Name:</td>
			<td><form:input path="lastName" /></td>
			<td><form:errors path="lastName" /></td>
			</tr>
			<tr>
			<td colspan="3">
			<input type="submit" value="Submit" />
			</td>
			</tr>
		</table>
</form:form>

The HTML of the above page would look like this :

<form method="POST">
	<span name="*.errors" class="errorBlock">Field is required.<br/>Field is required.</span>
	<table>
		<tr>
			<td>First Name:</td>
			<td><input name="firstName" type="text" value=""/></td>
			<td><span name="firstName.errors">Field is required.</span></td>
		</tr>
		
		<tr>
			<td>Last Name:</td>
			<td><input name="lastName" type="text" value=""/></td>
			<td><span name="lastName.errors">Field is required.</span></td>
		</tr>
		<tr>
			<td colspan="3">
			<input type="submit" value="Submit" />
			</td>
		</tr>
	</table>
</form>