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how to populate a response from java spring boot with thymleaf

I am trying to return the data as a response body in java spring boot when a button is click in an html page.I have a list of countries displayed in my page with an edit button assigned to each. I want to find the data that was clicked by id so I have defined the method in my controller class. That's when the edit button is click, it should take the id of the country in the clicked row and display the information based on that id. When I test the api in Postman, it returns the data correctly but when I called the same api in my html page, it's giving me this error.
org.thymeleaf.exceptions.TemplateProcessingException: Exception evaluating SpringEL expression: "/findById/{id=${country.id}}" (template: "country" - line 555, col 26)
at org.thymeleaf.spring5.expression.SPELVariableExpressionEvaluator.evaluate(SPELVariableExpressionEvaluator.java:292) ~[thymeleaf-spring5-3.0.14.RELEASE.jar:3.0.14.RELEASE]
Caused by: org.springframework.expression.spel.SpelParseException: Expression [/findById/{id=${country.id}}] #0: EL1070E: Problem parsing left operand
This is my data class
Entity
#Data
#NoArgsConstructor
#AllArgsConstructor
public class Country {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
private String code;
private String capital;
private String description;
private String nationality;
private String continent;
}
My Controller class
#Controller
public class CountryController {
#Autowired
private CountryService countryService;
#GetMapping("/countries")
public String getCountry(Model model){
List<Country> countryList = countryService.getAllCountry();
model.addAttribute("countries",countryList);
return "country";
}
#PostMapping("/countries/addNew")
public String saveInfo(Country country){
countryService.saveCountryInfo(country);
return "redirect:/countries";
}
#GetMapping("/findById/{id}")
#ResponseBody
public ResponseEntity<Country> getCountryById(#PathVariable("id") Long countryId){ //Bind PathVariable id to id
return ResponseEntity.ok(countryService.getCountryById(countryId)) ;
}
#GetMapping("/country/code/{code}")
public Country getCountryCode(#PathVariable("code") String code){
return countryService.getCountryByCode(code);
}
}
My Service class
#Service
public class CountryService {
#Autowired
private CountryRepository countryRepository;
public List<Country> getAllCountry() {
return countryRepository.findAll();
}
public void saveCountryInfo(Country country){
countryRepository.save(country);
}
public Country getCountryById(Long id){
return countryRepository.findById(id).get();
}
public Country getCountryByCode(String code){
return countryRepository.findByCode(code);
}
}
My Repository class
#Repository
public interface CountryRepository extends JpaRepository<Country,Long> {
public Country findByCode(String code);
}
Here is the html code
<section class="section dashboard">
<div class="row">
<!-- Left side columns -->
<div class="row">
<div class="col-lg-9 col-md-12">
<div class="panel panel-default">
<div class="panel-heading">
<!-- Image background -->
<button type="button" class="btn btn-primary" data-bs-toggle="modal" data-bs-target="#addModal" data-whatever="#mdo">Add A Country</button>
<h1>List of Country</h1>
<table class="table">
<thead>
<tr>
<th>Id</th>
<th>Code</th>
<th>Capital</th>
<th>Description</th>
<th>Nationality</th>
<th>Continent</th>
<th>Actions</th>
</tr>
</thead>
<tbody>
<tr th:each="country:${countries}">
<td th:text="${country.id}"></td>
<td th:text="${country.code}">Code</td>
<td th:text="${country.capital}">Capital</td>
<td th:text="${country.description}">Description</td>
<td th:text="${country.nationality}">Nationality</td>
<td th:text="${country.continent}">Continent</td>
<td>
<div class="btn-group">
<a th:href="${/findById/{id=${country.id}}}" class="btn btn-primary" id="editButton" data-bs-toggle="modal" data-bs-target="#editModal">Edit</a>
</div>
</td>
</tr>
</tbody>
</table>
</div><!-- End of Image background -->
</div><!-- End Left side columns -->
</div>
</div>
</div>
</section>

Error ID is null when should be auto-incremented

I'm trying to create a web form that allows a user to add an item to a database. Problem is when I submit said form I get the following error:
Field error in object 'products' on field 'id': rejected value [null]; codes [typeMismatch.products.id,typeMismatch.id,typeMismatch.int,typeMismatch]; arguments
Here's my jsp page:
<%# page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="ISO-8859-1">
<title>Add Item Page</title>
</head>
<body>
<h1> Add an Item </h1>
<form action="/addItem" method="post">
<div class="form-group">
<label for="name">Name</label>
<input class="form-control" type = "text" id="name" name="name" required minlength="2" autocomplete="off">
</div>
<div class="form-group">
<label for="price">Price</label>
<input class="form-control" type = "text" id="price" name="price" required>
</div>
<div class="form-group">
<label for="quantity">Quantity</label>
<input class="form-control" type="number" id="quantity" name="quantity" required>
</div>
<div class="form-group">
<label for="foodGroup">Food Group</label>
<input class="form-control" type="text" id="foodGroup" name="foodgroup" required>
</div>
<button type="submit" class="btn btn-primary" value="submit">Add Product</button>
</form>
Home
</body>
Here's the relevant part of my Products class (the rest is typical getter/setter/toString. I also left out the package line at the top):
import javax.persistence.*;
#Entity
#Table(name="products")
public class Products
{
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
int id;
String name;
String foodgroup;
int quantity;
Float price;
String image;
private Products() {}
public Products(int id, String name, int quantity, float price, String foodgroup, String image)
{
this.id = id;
this.name = name;
this.quantity = quantity;
this.foodgroup = foodgroup;
this.price = price;
this.image = image;
}
public int getId()
{
return id;
}
public void setId(int id)
{
this.id = id;
}
and finally the controller:
#Controller
public class MainController
{
#Autowired
private ProductsDAO productsDAO;
#GetMapping("/")
public ModelAndView showHome()
{
ModelAndView mav = new ModelAndView("index");
return mav;
}
#RequestMapping("/showProducts")
public ModelAndView showProducts()
{
List<Products> leListOfProducts = productsDAO.findAll();
ModelAndView mav = new ModelAndView("showProducts", "product", leListOfProducts);
return mav;
}
#RequestMapping("/addItem")
public ModelAndView showAddItemPage()
{
return new ModelAndView("addItem");
}
#PostMapping("/addItem")
public ModelAndView addProduct(Products product)
{
productsDAO.create(product);
return new ModelAndView("redirect:/index");
}
}
Here's a pic of the table columns and their settings.
I really appreciate any and all help ya'll can provide!
Best,
JBird

I suspect that your constructor is the issue there. Try removing the id in the constructor, as it is being generated by 3rd party means. Also, I don't think you will ever need the setId() method for any sane reason.

Trying to create a composite jpa object in Spring + Thymeleaf

I've tried to create an object with another object inside, with a form but the Object picked from a dropdown list gets converted into a String when returned from the Thymeleaf form.
Those are the entities in my project, with an 1:n relatioship between them:
Entity User
//imports
#Entity
#Table(name = "USERS")
public class User {
#Id
#GeneratedValue
#Column( name ="USER_ID")
private int id;
#Column( name ="username")
private String username;
#Column( name ="password")
private String password;
#Column( name ="email")
private String email;
#OneToMany(fetch= FetchType.LAZY, mappedBy="user", cascade = CascadeType.ALL)
private List<Post> posts;
//setter & getters & toString
}
Entity Post
//imports
#Entity
#Table(name="POSTS")
public class Post {
#Id
#GeneratedValue
#Column(name="POST_ID")
private int id;
#Column(name="tittle")
private String tittle;
#Column(name="text")
private String text;
#ManyToOne
#JoinColumn(name="USER_ID",referencedColumnName="USER_ID")
private User user;
//getters & setters & toString
To create a new Post:
//In Controller
#RequestMapping(value = "/posts/new")
public String newPost(Model model) {
model.addAttribute("post", new Post());
model.addAttribute("users", userService.list());
return "addPost";
}
Which returns the template that has this form:
<form th:action="#{/savePost}" th:object="${post}" method="post">
<tr>
<td><input type="hidden" th:field="${post.id}" /></td>
</tr>
<tr>
<td>Titulo</td>
<td>Texto</td>
<td>Usuario</td>
</tr>
<tr>
<td><input type="text" th:field="${post.tittle}"
th:value="${post.tittle}" /></td>
<td><input type="text" th:field="${post.text}"
th:value="${post.text}" /></td>
<td><select th:field="${post.user}">
<option th:each="user : ${users}" th:text="${user.username}"
th:value="${user.id}"></option>
</select></td>
</tr>
<tr>
<td colspan="3"><input class="btn btn-primary" type="submit"
value="GUARDAR"></td>
</tr>
</form>
The action attribute in the form calls:
#PostMapping("/savePost")
//#RequestMapping(value = "users/save",method = RequestMethod.POST)
public String savePost(#ModelAttribute Post post) {
postService.add(post);
return "redirect:/posts";
}
At this point, I try to create a Post and select a User from the dropdown but when attempting to save it gives me this error:
Field error in object 'post' on field 'user': rejected value [16]; codes [typeMismatch.post.user,typeMismatch.user,typeMismatch.com.julian.bootmvchibernate.model.User,typeMismatch]; arguments [org.springframework.context.support.DefaultMessageSourceResolvable: codes [post.user,user]; arguments []; default message [user]]; default message [Failed to convert property value of type 'java.lang.String' to required type 'com.julian.bootmvchibernate.model.User' for property 'user'; nested exception is org.springframework.core.convert.ConversionFailedException: Failed to convert from type [java.lang.String] to type [#javax.persistence.ManyToOne #javax.persistence.JoinColumn com.julian.bootmvchibernate.model.User] for value '16'; nested exception is java.lang.NullPointerException]
So I tried to implement a Formatter like so:
public class UserFormatter implements Formatter<User> {
#Autowired
#Qualifier("userService")
public GeneralService<User> userService;
#Override
public String print(User object, Locale locale) {
return (object != null ? object.getUsername() : "");
}
#Override
public User parse(String text, Locale locale) throws ParseException {
final Integer userId = Integer.parseInt(text);
return userService.get(userId);
}
}
Registering it:
#SpringBootApplication
public class BootmvchibernateApplication implements WebMvcConfigurer{
#SuppressWarnings("unchecked")
#Override
public void addFormatters(FormatterRegistry registry) {
registry.addFormatter(new UserFormatter());
}
public static void main(String[] args) {
SpringApplication.run(BootmvchibernateApplication.class, args);
}
}
But when this approach is tried the next error is found, this just uppon accessing the /post/new direcction (the template addPost doesn't work):
An error happened during template parsing (template: "class path resource [templates/addPost2.html]")
org.thymeleaf.exceptions.TemplateInputException: An error happened during template parsing (template: "class path resource [templates/addPost2.html]")
.....
Caused by: org.attoparser.ParseException: Error during execution of processor 'org.thymeleaf.spring5.processor.SpringOptionFieldTagProcessor' (template: "addPost2" - line 43, col 8)
.....
Caused by: org.springframework.core.convert.ConversionFailedException: Failed to convert from type [java.lang.String] to type [#javax.persistence.ManyToOne #javax.persistence.JoinColumn com.julian.bootmvchibernate.model.User] for value '2'; nested exception is java.lang.NullPointerException
at org.springframework.core.convert.support.ConversionUtils.invokeConverter(ConversionUtils.java:47)
If any more information is needed, tell me and I post it.
EDIT: this is the repository if someone is interested.
github.com/JulianBautistaVelez/JPA_Spring_Excercise

The problem is in your addPost.html except that everything is ok now.
<table>
<form th:action="#{/posts/new/mod}" th:object="${post}"
method="POST">
<tr>
<td><input type="hidden" th:field="${post.id}" /></td>
</tr>
<tr>
<td>Titulo</td>
<td>Texto</td>
<td>Usuario</td>
</tr>
<tr>
<td><input type="text" th:field="${post.tittle}"
th:value="${post.tittle}" /></td>
<td><input type="text" th:field="${post.text}"
th:value="${newPost.text}" /></td>
<!-- <td><select th:field="${newPost.user}">
<option th:each="user : ${users}" th:text="${user.username}"
th:value="${user.id}"></option>
</select></td> -->
<td><select th:field="*{user}" class="form-control">
<option th:each="user: ${users}"
th:value="${user.id}" th:text="${user.username}"></option>
</select></td>
</tr>
<tr>
<td colspan="3"><input class="btn btn-primary" type="submit"
value="GUARDAR"></td>
</tr>
</form>
</table>
I changed newPost as post , because you are adding in here as post model.
#RequestMapping(value = "/posts/new")
public String newPost(Model model) {
logger.info("-- en NEW Usuario");
model.addAttribute("post", new Post());
model.addAttribute("users", userService.list());
logger.info("-- -- -- LISTA DE USUARIOS -- -- --");
System.out.println(userService.list());
return "addPost";
}

Spring Boot, Thymeleaf Validation for Composition Class

How can I validate a composition relationship in Thymeleaf/Spring Boot. I have a simple FundTrf class which "has a" Data class. Problem is when I validate form inputs, FundTrf class related fields are getting validated, but the Data class related fields are not getting validated. Is there additional biding needs to be done between these classes. Below is what I have tried.
<!DOCTYPE HTML>
<html xmlns:th="http://www.thymeleaf.org">
<head>
<title>HNB CEFT | Test Bed</title>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
</head>
<body>
<h1>Form</h1>
<form action="#" th:action="#{/ceft/fundTrf}" th:object="${fundTrf}" method="post">
<table>
<tr><td>Version </td><td><input type="text" th:field="*{version}" /></td>
<td th:if="${#fields.hasErrors('version')}" th:errors="*{version}">Version Error</td>
</tr>
<tr><td>Bank Code </td><td><input type="text" th:field="*{data.dest_bank_code}" /></td>
<td th:if="${#fields.hasErrors('data.dest_bank_code')}" th:errors="*{data.dest_bank_code}">Bank Code Error</td>
</tr>
<tr><td>Amount </td><td><input type="text" th:field="*{data.amount}" /></td>
<td th:if="${#fields.hasErrors('data.amount')}" th:errors="*{data.amount}">Amount Error</td>
</tr>
</table>
<p><input type="submit" value="Submit" /> <input type="reset" value="Reset" /></p>
</form>
</body>
</html>
Below is my controller class.
#Controller
public class Hello implements WebMvcConfigurer{
#GetMapping("/ceft/welcome")
public String welcomeForm(Model model) {
model.addAttribute("fundTrf", new FundTrf());
return "welcome";
}
#PostMapping("/ceft/fundTrf")
public String ceftTransaction(#ModelAttribute #Valid FundTrf fundTrf, BindingResult bindingResult) {
if (bindingResult.hasErrors()) {
return "welcome";
} else {
return "result";
}
}
}
Below is my FundTrf class
public class FundTrf {
#NotEmpty
private String version;
private Data data;
..Getters and Setters
}
And this is the Data class.
public class Data {
#NotEmpty
private String reqId;
#NotEmpty
private String frm_hnb_account;
#NotEmpty
private String dest_bank_account;
#NotEmpty
private String benificiary_name;
#NotEmpty
private String dest_bank_code;
#NotEmpty
#Size(min = 2, max = 30)
private String amount;
..Getters and Setters
}
The issue is when I submit the form with empty values the message "Version must not be empty" is coming up, but Amount validation is not working. What am I doing wrong here?

You have to set #Valid on the object Data in order for your Data properties to be also validated.
public class FundTrf {
#NotEmpty
private String version;
#Valid //ADDED VALID HERE
private Data data;
..Getters and Setters
}
The javadoc for javax.validation.Valid says:
Marks a property, method parameter or method return type for
validation cascading. Constraints defined on the object and its
properties are be validated when the property, method parameter or
method return type is validated. This behavior is applied recursively.

Spring 3 RadioButtonsTag Attribute 'items' must be an array, a Collection or a Map Exception

I am populate a List of String as radio button in the JSP. I add the List to the ModelMap but still the below Exception occurred. What am i missing please?
Attribute 'items' must be an array, a Collection or a Map:
java.lang.IllegalArgumentException: Attribute 'items' must be an
array, a Collection or a Map
#Controller
public class EmployeeController {
#Autowired
private EmployeeManager employeeManager;
#RequestMapping(value = {"/"}, method = RequestMethod.GET)
public String homePage(ModelMap map) {
map.addAttribute("employee", new Employee());
populateDepartments(map);
return "addEmployee";
}
private void populateDepartments(ModelMap map){
List<String> departments = new ArrayList<String>();
departments.add("Dept 1");
departments.add("Dept 2");
map.addAttribute("departments",departments);
}
}
addEmployee.jsp:
<form:form method="post" action="add" commandName="employee">
<table>
<tr>
<td><form:label path="name">Name</td>
<td><form:input path="name" /></td>
<td>Address</td>
<td><form:input path="address" /></td>
<td>Departments</td>
<td><form:radiobuttons path="empDepartment" items="${departments}"/></td>
</tr>
<tr>
<td colspan="2">
<input type="submit" value="Add"/>
</td>
</tr>
</table>
</form:form>
The entity
#Entity
public class Employee {
#Id
#GeneratedValue(strategy=GenerationType.AUTO)
private Integer id;
private String name;
private String address;
#Transient
private String empDepartment;
}