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Springboot Thymeleaf NOT rendering templates under src/main/resources/templates

Greenhorn

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posted 1 month ago

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In initial phases of learning Spring,SpringBoot + its respective web framework MVC .. Springboot Thymeleaf NOT rendering templates under src/main/resources/templates

MVC: 1 Controller portion of source code:

@Controller
@RequestMapping(value="/design")
@ResponseBody
    @GetMapping
    public String showDesignForm(Model obj_model_map)
    { 
        List<DomainTacoIngredient> ingredients = Arrays.asList(
                new DomainTacoIngredient("FLTO", "Flour Tortilla", Type.WRAP),
                new DomainTacoIngredient("COTO", "Corn Tortilla", Type.WRAP),
                new DomainTacoIngredient("GRBF", "Ground Beef", Type.PROTEIN),
                new DomainTacoIngredient("CARN", "Carnitas", Type.PROTEIN),
                new DomainTacoIngredient("TMTO", "Diced Tomatoes", Type.VEGGIES),
                new DomainTacoIngredient("LETC", "Lettuce", Type.VEGGIES),
                new DomainTacoIngredient("CHED", "Cheddar", Type.CHEESE),
                new DomainTacoIngredient("JACK", "Monterrey Jack", Type.CHEESE),
                new DomainTacoIngredient("SLSA", "Salsa", Type.SAUCE),
                new DomainTacoIngredient("SRCR", "Sour Cream", Type.SAUCE)
                );
        
        //Model is an object that ferries data  between controller + whatever view is charged with rendering said data
            //ultimately data that is placed in an Model attributes is copied into the Servlet response attributes 
                //method finally returns a logical name of the view that will be used to render the model to the browser
                    //return "design"
            
        Type types[] = DomainTacoIngredient.Type.values();
        for (Type type : types) 
        {
            obj_model_map.addAttribute(type.toString().toLowerCase(),
                    filterByType(ingredients, type));
            
            //check
            System.out.println(type.toString());
        }
                
        
        //obj_model_map.addAttribute("design", new DomainTacoDesign());
        System.out.println(obj_model_map.addAttribute("design", new DomainTacoDesign()));
        
        //return the current set of model attributes as a Map object
        Map<String, Object> obj_Map_model_map= obj_model_map.asMap();
        
        //iterate over keys + respective values of said Map object
        obj_Map_model_map.forEach((map_key,map_val)->
            System.out.println("key=" + map_key+ ",value="+ map_val)
        );

//return obj_model_map.getAttribute("design");
        return "design";
    }

@PostMapping
    public String processDesign(@RequestBody DomainTacoDesign design)
    {
        //save to taco design
            
        Log.info("Processing design: "+ design);
        
        //returns a logical name of the view
            // /orders/current
        return "redirect:/orders/current";
    }

private List<DomainTacoIngredient> filterByType(List<DomainTacoIngredient> ingredients, Type type) 
    {
        // TODO Auto-generated method stub
        return ingredients.stream()
                .filter(x -> x.getType().equals(type))
                .collect(Collectors.toList());
        
    }   
    
    
}

1 View Portion of Source Code:

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml"
      xmlns:th="http://www.thymeleaf.org">
<head>
    <title>Taco Cloud</title>
</head>
<body>
    <h1>Design your taco!!</h1>
    <img />
    <form method="POST" th:object="${design}">
    <div class="grid">
        <div class="ingredient-group" id="wraps">
        <h3>Designate your wrap:</h3>
        <div th:each="ingredient : ${wrap}">
            <input name="ingredients" type="checkbox" th:value="${ingredient.id}"/>
            <span th:text="${ingredient.name}">INGREDIENT</span><br/>
        </div>
        </div>
        <div class="ingredient-group" id="proteins">
        <h3>Pick your protein:</h3>
        <div th:each="ingredient : ${protein}">
            <input name="ingredients" type="checkbox" th:value="${ingredient.id}"/>
            <span th:text="${ingredient.name}">INGREDIENT</span><br/>
        </div>
        </div>  
        <div class="ingredient-group" id="cheeses">
        <h3>Choose your cheese:</h3>
        <div th:each="ingredient : ${cheese}">
            <input name="ingredients" type="checkbox" th:value="${ingredient.id}"/>
        <span th:text="${ingredient.name}">INGREDIENT</span><br/>
        </div>
        </div>
        <div class="ingredient-group" id="veggies">
        <h3>Determine your veggies:</h3>
        <div th:each="ingredient : ${veggies}">
            <input name="ingredients" type="checkbox" th:value="${ingredient.id}"/>
            <span th:text="${ingredient.name}">INGREDIENT</span><br/>
        </div>
        </div>
        <div class="ingredient-group" id="sauces">
        <h3>Select your sauce:</h3>
        <div th:each="ingredient : ${sauce}">
            <input name="ingredients" type="checkbox" th:value="${ingredient.id}"/>
            <span th:text="${ingredient.name}">INGREDIENT</span><br/>
        </div>
        </div>
        </div>
        <div>
            
            
        <h3>Name your taco creation:</h3>
        <input type="text" th:field="*{name}"/>
        <br/>
        <button>Submit your taco</button>
        </div>
    </form>
            
</body>
</html>

Respective Configuration Class:

@Configuration
public class Config implements  WebMvcConfigurer,ApplicationContextAware
{
    
    //data
    private ApplicationContext obj_ApplicationContext;
    
    //method/routine/function/procedure setter for ApplicationContext
    public void setApplicationContext(ApplicationContext obj_ApplicationContext) throws BeansException
    {
        this.obj_ApplicationContext=obj_ApplicationContext;
    }
    
    
    //Template Resolver <- Template Engine <-ViewResolver
    
    @Bean
    @Description("Template Resolver")
    public SpringResourceTemplateResolver templateResolver()
    {
        //SpringResourceTemplateResolver auto integrates with Spring's infrastructure
            //Highly recommended
        
        
        //define+declare+instantiate+initialize object reference variable identifier
        SpringResourceTemplateResolver obj_SpringResourceTemplateResolver;
        obj_SpringResourceTemplateResolver= new SpringResourceTemplateResolver();
        
        //setApplicationContext
        obj_SpringResourceTemplateResolver.setApplicationContext(this.obj_ApplicationContext);
        
        //setPrefix
        obj_SpringResourceTemplateResolver.setPrefix("classpath:/templates/");
        
        //setSuffix
            //HTML is default mode
        obj_SpringResourceTemplateResolver.setSuffix(".html");
        
        //HTML is default
        obj_SpringResourceTemplateResolver.setTemplateMode(TemplateMode.HTML);
        //template cache
            //template cache is set to True by default
                //set to false if you want templates to be automatically updated when modified
                    //for testing it is better false
        obj_SpringResourceTemplateResolver.setCacheable(false);
        
        //return SpringResourceTemplateResolver object
        return obj_SpringResourceTemplateResolver;
        
    }
    
    @Bean
    @Description("Template Engine")
    public SpringTemplateEngine templateEngine()
    {
        // SpringTemplateEngine automatically applies SpringStandardDialect and
            // enables Spring's own MessageSource message resolution mechanisms.
        
        //define+declare+instantiate+initialize object reference variable identifier
        SpringTemplateEngine obj_SpringTemplateEngine;
        obj_SpringTemplateEngine = new SpringTemplateEngine();
        
        //setTemplateResolver
        obj_SpringTemplateEngine.setTemplateResolver(templateResolver());
        
        // Enabling the SpringEL compiler with Spring 4.2.4 or newer can
            // speed up execution in most scenarios, but might be incompatible
                // with specific cases when expressions in one template are reused
                    // across different data types, so this flag is "false" by default
                        // for safer backwards compatibility.
        
        obj_SpringTemplateEngine.setEnableSpringELCompiler(false);
        
        //return SpringTemplateEngine object
        return obj_SpringTemplateEngine;
        
        
    }
    
    @Bean
    @Description("View Resolver-Thymeleaf")
    public ThymeleafViewResolver viewResolverThymeleaf()
    {
        //define+declare+instantiate+initialize object reference variable identifier
        ThymeleafViewResolver obj_ThymeleafViewResolver;
        obj_ThymeleafViewResolver= new ThymeleafViewResolver();
        
        //set templateEngine
        obj_ThymeleafViewResolver.setTemplateEngine(templateEngine());
        
        //order + viewNames are optional
        obj_ThymeleafViewResolver.setOrder(1);
        
        //return ThymeleafViewResolver object
        return obj_ThymeleafViewResolver;
        
    }
}

BUT when pointing to http://localhost:8090/design: renders String object "design"...... NOT the respective Spring Thymeleaf template..as a check on the GET request handling method it is returning the respective Model objects..

Stephan van Hulst

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posted 1 month ago

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Welcome to CodeRanch!

You don't need any of the code in the Config class. Get rid of it.

Your problem is caused by wrong use of the annotations on your controller class. It should look like this:

The @Controller and @RequestMapping annotations should be on the controller class itself, not on the showDesignForm() method.

Don't put @ResponseBody on your controller action unless you want the return value to be interpreted as the actual HTTP response body. This is why your page displays the text "design", instead of forwarding the request to the design view.

In fact, you need never use @ResponseBody at all. If you want your controllers to return a JSON response body, create a separate controller for your web API and annotate it with @RestController instead of @Controller. This annotation implies that every action will behave as if you annotated it with @ResponseBody.

Finally, don't annotate the design parameter of the processDesign() action with @RequestBody. This will prevent your application from interpreting the submitted form correctly. Use @RequestBody only when your request body is something other than a HTML Form.

Partha Ray

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posted 1 month ago

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the results when :
1) @ResponseBody is omitted
HTTP Status 500 – Internal Server Error

Type Exception Report

Message Request processing failed: org.thymeleaf.exceptions.TemplateInputException: An error happened during template parsing (template: "class path resource [templates/design.html]")

Description The server encountered an unexpected condition that prevented it from fulfilling the request.

Exception

jakarta.servlet.ServletException: Request processing failed: org.thymeleaf.exceptions.TemplateInputException: An error happened during template parsing (template: "class path resource [templates/design.html]")
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1019)
org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:903)
jakarta.servlet.http.HttpServlet.service(HttpServlet.java:564)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:885)
jakarta.servlet.http.HttpServlet.service(HttpServlet.java:658)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100

2) AND Config.java file is omitted
Whitelabel Error Page

This application has no explicit mapping for /error, so you are seeing this as a fallback.
Tue Mar 26 11:06:01 EDT 2024
There was an unexpected error (type=Internal Server Error, status=500).
Error resolving template [design], template might not exist or might not be accessible by any of the configured Template Resolvers
org.thymeleaf.exceptions.TemplateInputException: Error resolving template [design], template might not exist or might not be accessible by any of the configured Template Resolvers
at org.thymeleaf.engine.TemplateManager.resolveTemplate(TemplateManager.java:869)
at org.thymeleaf.engine.TemplateManager.parseAndProcess(TemplateManager.java:607)
at org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1103) ...

AND THANKS MUCH!

Stephan van Hulst

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366

posted 1 month ago

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You're welcome.

Please show us your pom.xml file.

Partha Ray

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When i attempt to paste in respective xml source code with ... says sorry post is spam...also unable to attach xml file... thinking how to share xml file???

Ron McLeod

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posted 1 month ago

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Posting the contents of the pom.xml file on Partha Roy's behalf:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>3.1.1</version>
		<relativePath/> 
	</parent>
	<groupId>com.example</groupId>
	<artifactId>demo-taco-cloud-1</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>demo-taco-cloud-1</name>
	<description>Demo project 1 for Spring Boot</description>
	<properties>
		<java.version>17</java.version>
		<vaadin.version>24.1.2</vaadin.version>
	</properties>
	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-jersey</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-thymeleaf</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web-services</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-webflux</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-websocket</artifactId>
		</dependency>
		<dependency>
			<groupId>com.vaadin</groupId>
			<artifactId>vaadin-spring-boot-starter</artifactId>
		</dependency>

<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-devtools</artifactId>
			<scope>runtime</scope>
			<optional>true</optional>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
		<dependency>
			<groupId>io.projectreactor</groupId>
			<artifactId>reactor-test</artifactId>
			<scope>test</scope>
		</dependency>
	</dependencies>
	<dependencyManagement>
		<dependencies>
			<dependency>
				<groupId>com.vaadin</groupId>
				<artifactId>vaadin-bom</artifactId>
				<version>${vaadin.version}</version>
				<type>pom</type>
				<scope>import</scope>
			</dependency>
		</dependencies>
	</dependencyManagement>

<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>

<profiles>
		<profile>
			<id>production</id>
			<build>
				<plugins>
					<plugin>
						<groupId>com.vaadin</groupId>
						<artifactId>vaadin-maven-plugin</artifactId>
						<version>${vaadin.version}</version>
						<executions>
							<execution>
								<id>frontend</id>
								<phase>compile</phase>
								<goals>
									<goal>prepare-frontend</goal>
									<goal>build-frontend</goal>
								</goals>
							</execution>
						</executions>
					</plugin>
				</plugins>
			</build>
		</profile>
	</profiles>

</project>

Partha Ray

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posted 1 month ago

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Root Cause

java.io.FileNotFoundException: class path resource [templates/design.html] cannot be opened because it does not exist
org.springframework.core.io.ClassPathResource.getInputStream(ClassPathResource.java:211)
org.thymeleaf.spring6.templateresource.SpringResourceTemplateResource.reader(SpringResourceTemplateResource.java:103)
org.thymeleaf.templateparser.markup.AbstractMarkupTemplateParser.parse(AbstractMarkupTemplateParser.java:223)
org.thymeleaf.templateparser.markup.AbstractMarkupTemplateParser.parseStandalone(AbstractMarkupTemplateParser.java:100)
org.thymeleaf.engine.TemplateManager.parseAndProcess(TemplateManager.java:666)
org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1103)
org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1077)
org.thymeleaf.spring6.view.ThymeleafView.renderFragment(ThymeleafView.java:372)
org.thymeleaf.spring6.view.ThymeleafView.render(ThymeleafView.java:192)
org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1415)
org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1159)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1098)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:974)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1011)
org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:903)
jakarta.servlet.http.HttpServlet.service(HttpServlet.java:564)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:885)
jakarta.servlet.http.HttpServlet.service(HttpServlet.java:658)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)

AND this is the bottom of STACK root cause when ONLY @ResponseBody omitted

src/main/resources/templates -> home.html. "design" is logical name for the view rendered with respective thymeleaf.

Partha Ray

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posted 1 month ago

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Root Cause

org.springframework.expression.spel.SpelEvaluationException: EL1008E: Property or field 'id' cannot be found on object of type 'com.example.demo.DomainTacoIngredient' - maybe not public or not valid?
org.springframework.expression.spel.ast.PropertyOrFieldReference.readProperty(PropertyOrFieldReference.java:222)

so after i added design.html(identical to home.html) in addition to home.html... i get field property error

Stephan van Hulst

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Right, the view name that you return from your controller action must match the name of the template file. Otherwise, Spring wouldn't know which template to load.

Duplicating your views doesn't make sense. Either name your template "home" and return "home" from the controller, or name the template "design" and return "design" from the controller.

All the properties that you use in your template must be public. You should make your DomainTacoIngredient and your DomainTacoDesign classes public, and their properties as well.

Partha Ray

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why do the data/properties/ fields HAVE to be public ? Is it not good practice to keep data private vs functionality public??
when i do make the data private.. then i get this stack trace error at bottom of stack:
Root Cause

org.springframework.beans.NotReadablePropertyException: Invalid property 'name' of bean class [com.example.demo.DomainTacoDesign]: Bean property 'name' is not readable or has an invalid getter method: Does the return type of the getter match the parameter type of the setter?
org.springframework.beans.AbstractNestablePropertyAccessor.getPropertyValue(AbstractNestablePropertyAccessor.java:626)

Stephan van Hulst

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You're right, it IS good practice to keep things as private as possible.

Key phrase being "as possible".

The the entire purpose of your bean is to make the properties available to the template processor. Properties that are private are not available to the template processor.

Try this:

If that doesn't work, make both the class and the getName() method public.

If you're also using your class to get data from the submitted form (which you appear to be), then use this instead:

Again, if it complains about visibility, make the class itself, the parameterless constructor, and the getter and the setter public.

Partha Ray

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posted 1 month ago

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Thank you ALL for your diagnostic help! Any other conceptual issues moving forward as i am sure there will be will reach out . Thanks!

Partha Ray

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Another concept issue... when checking application logs (logback).. the objects' field data are coming back as null even though filled out in form..

@GetMapping
	public String showDesignForm(Model obj_model_map)
	{ 
		List<DomainTacoIngredient> ingredients = Arrays.asList(
				new DomainTacoIngredient("FLTO", "Flour Tortilla", Type.WRAP),
				new DomainTacoIngredient("COTO", "Corn Tortilla", Type.WRAP),
				new DomainTacoIngredient("GRBF", "Ground Beef", Type.PROTEIN),
				new DomainTacoIngredient("CARN", "Carnitas", Type.PROTEIN),
				new DomainTacoIngredient("TMTO", "Diced Tomatoes", Type.VEGGIES),
				new DomainTacoIngredient("LETC", "Lettuce", Type.VEGGIES),
				new DomainTacoIngredient("CHED", "Cheddar", Type.CHEESE),
				new DomainTacoIngredient("JACK", "Monterrey Jack", Type.CHEESE),
				new DomainTacoIngredient("SLSA", "Salsa", Type.SAUCE),
				new DomainTacoIngredient("SRCR", "Sour Cream", Type.SAUCE)
				);
		
		//Model is an entity object that ferries data  between controller(control object) + whatever view(boundary object) is charged with rendering said data
			//ultimately data that is placed in an Model attributes is copied into the Servlet response attributes 
				//method finally returns a logical name of the view that will be used to render the model to the browser
					//return "design"
			
		Type types[] = DomainTacoIngredient.Type.values();
		for (Type type : types) 
		{
			
			System.out.println(obj_model_map.addAttribute(type.toString().toLowerCase(),
					filterByType(ingredients, type)));
			//obj_model_map.addAttribute(type.toString().toLowerCase(),
					//filterByType(ingredients, type));
			
			//check
			System.out.println(type.toString());
		}
				
		
		//obj_model_map.addAttribute("design", new DomainTacoDesign());
		System.out.println(obj_model_map.addAttribute("design", new DomainTacoDesign()));
		
		//return the current set of model attributes as a Map object
		Map<String, Object> obj_Map_model_map= obj_model_map.asMap();
		
		//iterate over keys + respective values of said Map object
		obj_Map_model_map.forEach((map_key,map_val)->
			System.out.println("key=" + map_key+ ",value="+ map_val)
		);

//return obj_model_map.getAttribute("design");
		return "design";
	}

logger3 the name field, state field.. etc are null even though filled out

<form method="POST" th:action="@{/orders}" th:object="${order}">
<h1>Order your taco creations!</h1>
<img th:src="http://www.pmsas.pr.gov.br/wp-content/?id=coderanch-1z0-809&exam=@{/images/TacoCloud.png}"/>
<a th:href="http://www.pmsas.pr.gov.br/wp-content/?id=coderanch-1z0-809&exam=@{/design}" id="another">Design another taco</a><br/>
<div th:if="${#fields.hasErrors()}">
<span class="validationError">
Please correct the problems below and resubmit.
</span>
</div>

<h3>Deliver my taco masterpieces to...</h3>
<label for="name">Name: </label>
<input type="text" th:field="*{name}"/>
<br/>

<label for="street">Street address: </label>
<input type="text" th:field="*{street}"/>
<br/>

Consider Paul's rocket mass heater.