I am using two tables:
with a many (Repairs) to one (Terminal) relationship. I am trying to populate a Thymeleaf form to create a new repair. One of the fields is a dropdown to select the Terminal but I am getting a java.lang.IllegalArgumentException: A null value cannot be assigned to a primitive type error. This is my code:
Entity:
public class Repair {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long repairId;
@ManyToOne(targetEntity = Terminal.class)
@JoinColumn(nullable = false)
private Terminal terminal;
@Column(name = "date_received", nullable = false)
private Date dateReceived;
@Column(name = "date_ready")
private Date dateReady;
@Column(name = "fault")
private String fault;
@Column(name = "solution")
private String solution;
//constructors, getters & setters
public class Terminal {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(nullable = false)
private long terminalId;
@Column(nullable = false)
private String ptid;
@ManyToOne(targetEntity = TerminalModel.class)
@JoinColumn(nullable = false)
private TerminalModel terminalModel;
//constructors, getters & setters
Controller:
@GetMapping("/repair/repairs/new")
public String createRepairForm(Model model){
List<Terminal> terminals = terminalService.getAllTerminals();
Repair repair = new Repair();
model.addAttribute("terminals", terminals);
model.addAttribute("repair", repair);
return "repair/create-repair";
}
View:
<form th:action="@{/repairs}" th:object="${repair}" method="POST">
<div class="form-group">
<label>Date Received</label>
<input type="text" name="dateReceived" th:field = "*{dateReceived}" class="form-control" placeholder="Enter Date Received"/>
</div>
<div class="form-group">
<label>Date Ready</label>
<input type="text" name="dateReady" th:field = "*{dateReady}" class="form-control" placeholder="Enter Date Ready"/>
</div>
<div class="form-group">
<label>Fault</label>
<input type="text" name="fault" th:field = "*{fault}" class="form-control" placeholder="Enter Fault"/>
</div>
<div class="form-group">
<label>Solution</label>
<input type="text" name="solution" th:field = "*{solution}" class="form-control" placeholder="Enter Solution"/>
</div>
<div class="form-group">
<label for="terminal">Terminal:</label>
<select id="terminal" name="terminal.terminalId" th:field="*{terminal.terminalId}">
<option value="">-- Select Terminal --</option>
<option th:each="terminal : ${terminals}" th:value="${terminal.terminalId}" th:text="${terminal.ptid}">
</option>
</select>
</div>
<div class="footer-body">
<button type="submit" class="btn btn-primary"> Submit </button>
</div>
</form>
This is part of the trace:
Caused by: org.springframework.core.convert.ConversionFailedException: Failed to convert from type [java.lang.String] to type [@jakarta.persistence.Id @jakarta.persistence.GeneratedValue @jakarta.persistence.Column long] for value 'null'
at org.springframework.core.convert.support.GenericConversionService.assertNotPrimitiveTargetType(GenericConversionService.java:335) ~[spring-core-6.0.7.jar:6.0.7]
at org.springframework.core.convert.support.GenericConversionService.handleResult(GenericConversionService.java:328) ~[spring-core-6.0.7.jar:6.0.7]
at org.springframework.core.convert.support.GenericConversionService.convert(GenericConversionService.java:193) ~[spring-core-6.0.7.jar:6.0.7]
at org.springframework.core.convert.support.ConvertingPropertyEditorAdapter.setAsText(ConvertingPropertyEditorAdapter.java:60) ~[spring-core-6.0.7.jar:6.0.7]
at org.thymeleaf.spring6.util.SpringSelectedValueComparator.exhaustiveCompare(SpringSelectedValueComparator.java:173) ~[thymeleaf-spring6-3.1.1.RELEASE.jar:3.1.1.RELEASE]
at org.thymeleaf.spring6.util.SpringSelectedValueComparator.isSelected(SpringSelectedValueComparator.java:90) ~[thymeleaf-spring6-3.1.1.RELEASE.jar:3.1.1.RELEASE]
at org.thymeleaf.spring6.processor.SpringOptionFieldTagProcessor.doProcess(SpringOptionFieldTagProcessor.java:68) ~[thymeleaf-spring6-3.1.1.RELEASE.jar:3.1.1.RELEASE]
at org.thymeleaf.spring6.processor.AbstractSpringFieldTagProcessor.doProcess(AbstractSpringFieldTagProcessor.java:187) ~[thymeleaf-spring6-3.1.1.RELEASE.jar:3.1.1.RELEASE]
at org.thymeleaf.processor.element.AbstractAttributeTagProcessor.doProcess(AbstractAttributeTagProcessor.java:74) ~[thymeleaf-3.1.1.RELEASE.jar:3.1.1.RELEASE]
... 52 common frames omitted
Caused by: java.lang.IllegalArgumentException: A null value cannot be assigned to a primitive type
... 61 common frames omitted
2023-08-25T08:48:04.115+02:00 ERROR 28912 --- [nio-8080-exec-5] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed: org.thymeleaf.exceptions.TemplateProcessingException: Error during execution of processor 'org.thymeleaf.spring6.processor.SpringOptionFieldTagProcessor' (template: "repair/create-repair" - line 60, col 17)] with root cause
java.lang.IllegalArgumentException: A null value cannot be assigned to a primitive type
How do I fix this?
The error indicates that a primitive type (such as int, long, ...) cannot have null assigned to it. The Java language does not allow this.
If you want to allow null values, you need to use a wrapper (e.g. Integer, Long, ...).
I see you have private long terminalId;. Try changing this to private Long terminalId;
PS: A better alternative is to use a dedicated form data object so you only need to change it to Long in the form data object and keep your entity like you want. See https://www.wimdeblauwe.com/blog/2021/05/23/form-handling-with-thymeleaf/ for more info.