Issues with Form Submission in Spring Boot App using Thymeleaf - spring-boot

Question

I have this basic application written in Spring Boot, with a Web Controller. I included a HTML form to add some input which will save the inputs using the JpaRepository save method.
I am using Thymeleaf as my templating engine and MySql as DB. When I run the app, it runs just fine. However, when i hit the page localhost:8080/addExpense, it gives a white label error page with the following error:
There was an unexpected error (type=Internal Server Error,
status=500).
Error during execution of processor 'org.thymeleaf.spring5.processor.SpringInputGeneralFieldTagProcessor'
(template: "addExpense" - line 19, col 49)
I think the issue is with this code
th:field="*{expense}"
My IDE console prints the following error:
org.thymeleaf.exceptions.TemplateProcessingException: Error during
execution of processor
'org.thymeleaf.spring5.processor.SpringInputGeneralFieldTagProcessor'
(template: "addExpense" - line 19, col 49) at
org.thymeleaf.processor.element.AbstractAttributeTagProcessor.doProcess(AbstractAttributeTagProcessor.java:117)
~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE] at
org.thymeleaf.processor.element.AbstractElementTagProcessor.process(AbstractElementTagProcessor.java:95)
~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE] at
org.thymeleaf.util.ProcessorConfigurationUtils$ElementTagProcessorWrapper.process(ProcessorConfigurationUtils.java:633)
~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE] at
org.thymeleaf.engine.ProcessorTemplateHandler.handleStandaloneElement(ProcessorTemplateHandler.java:918)
~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE] at
org.thymeleaf.engine.StandaloneElementTag.beHandled(StandaloneElementTag.java:228)
~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE] at
org.thymeleaf.engine.TemplateModel.process(TemplateModel.java:136)
~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE] at
org.thymeleaf.engine.TemplateManager.parseAndProcess(TemplateManager.java:661)
~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE] at
org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1098)
[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE] at
org.thymeleaf.TemplateEngine.process(TemplateEngine.java:1072)
[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE] at
org.thymeleaf.spring5.view.ThymeleafView.renderFragment(ThymeleafView.java:354)
[thymeleaf-spring5-3.0.9.RELEASE.jar:3.0.9.RELEASE] at
org.thymeleaf.spring5.view.ThymeleafView.render(ThymeleafView.java:187)
[thymeleaf-spring5-3.0.9.RELEASE.jar:3.0.9.RELEASE] at
org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1325)
[spring-webmvc-5.0.6.RELEASE.jar:5.0.6.RELEASE] at
org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1069)
[spring-webmvc-5.0.6.RELEASE.jar:5.0.6.RELEASE] at
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1008)
[spring-webmvc-5.0.6.RELEASE.jar:5.0.6.RELEASE] at
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:925)
[spring-webmvc-5.0.6.RELEASE.jar:5.0.6.RELEASE] at
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:974)
[spring-webmvc-5.0.6.RELEASE.jar:5.0.6.RELEASE] at
org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:866)
[spring-webmvc-5.0.6.RELEASE.jar:5.0.6.RELEASE] at
javax.servlet.http.HttpServlet.service(HttpServlet.java:635)
[tomcat-embed-core-8.5.31.jar:8.5.31] at
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:851)
[spring-webmvc-5.0.6.RELEASE.jar:5.0.6.RELEASE] at
javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
[tomcat-embed-core-8.5.31.jar:8.5.31] at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
[tomcat-embed-core-8.5.31.jar:8.5.31] at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
[tomcat-embed-core-8.5.31.jar:8.5.31] at
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
[tomcat-embed-websocket-8.5.31.jar:8.5.31] at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
[tomcat-embed-core-8.5.31.jar:8.5.31] at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
[tomcat-embed-core-8.5.31.jar:8.5.31] at
org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99)
[spring-web-5.0.6.RELEASE.jar:5.0.6.RELEASE] at
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
[spring-web-5.0.6.RELEASE.jar:5.0.6.RELEASE] at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
[tomcat-embed-core-8.5.31.jar:8.5.31] at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
[tomcat-embed-core-8.5.31.jar:8.5.31] at
org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:109)
[spring-web-5.0.6.RELEASE.jar:5.0.6.RELEASE] at
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
[spring-web-5.0.6.RELEASE.jar:5.0.6.RELEASE] at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
[tomcat-embed-core-8.5.31.jar:8.5.31] at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
[tomcat-embed-core-8.5.31.jar:8.5.31] at
org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:81)
[spring-web-5.0.6.RELEASE.jar:5.0.6.RELEASE] at
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
[spring-web-5.0.6.RELEASE.jar:5.0.6.RELEASE] at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
[tomcat-embed-core-8.5.31.jar:8.5.31] at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
[tomcat-embed-core-8.5.31.jar:8.5.31] at
org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200)
[spring-web-5.0.6.RELEASE.jar:5.0.6.RELEASE] at
org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
[spring-web-5.0.6.RELEASE.jar:5.0.6.RELEASE] at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
[tomcat-embed-core-8.5.31.jar:8.5.31] at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
[tomcat-embed-core-8.5.31.jar:8.5.31] at
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198)
[tomcat-embed-core-8.5.31.jar:8.5.31] at
org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
[tomcat-embed-core-8.5.31.jar:8.5.31] at
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:496)
[tomcat-embed-core-8.5.31.jar:8.5.31] at
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
[tomcat-embed-core-8.5.31.jar:8.5.31] at
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
[tomcat-embed-core-8.5.31.jar:8.5.31] at
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
[tomcat-embed-core-8.5.31.jar:8.5.31] at
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
[tomcat-embed-core-8.5.31.jar:8.5.31] at
org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:803)
[tomcat-embed-core-8.5.31.jar:8.5.31] at
org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
[tomcat-embed-core-8.5.31.jar:8.5.31] at
org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:790)
[tomcat-embed-core-8.5.31.jar:8.5.31] at
org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1468)
[tomcat-embed-core-8.5.31.jar:8.5.31] at
org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
[tomcat-embed-core-8.5.31.jar:8.5.31] at
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
[na:1.8.0_161] at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
[na:1.8.0_161] at
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
[tomcat-embed-core-8.5.31.jar:8.5.31] at
java.lang.Thread.run(Thread.java:748) [na:1.8.0_161] Caused by:
java.lang.IllegalStateException: Neither BindingResult nor plain
target object for bean name 'expense' available as request attribute
at
org.springframework.web.servlet.support.BindStatus.(BindStatus.java:153)
~[spring-webmvc-5.0.6.RELEASE.jar:5.0.6.RELEASE] at
org.springframework.web.servlet.support.RequestContext.getBindStatus(RequestContext.java:903)
~[spring-webmvc-5.0.6.RELEASE.jar:5.0.6.RELEASE] at
org.thymeleaf.spring5.context.webmvc.SpringWebMvcThymeleafRequestContext.getBindStatus(SpringWebMvcThymeleafRequestContext.java:227)
~[thymeleaf-spring5-3.0.9.RELEASE.jar:3.0.9.RELEASE] at
org.thymeleaf.spring5.util.FieldUtils.getBindStatusFromParsedExpression(FieldUtils.java:305)
~[thymeleaf-spring5-3.0.9.RELEASE.jar:3.0.9.RELEASE] at
org.thymeleaf.spring5.util.FieldUtils.getBindStatus(FieldUtils.java:252)
~[thymeleaf-spring5-3.0.9.RELEASE.jar:3.0.9.RELEASE] at
org.thymeleaf.spring5.util.FieldUtils.getBindStatus(FieldUtils.java:226)
~[thymeleaf-spring5-3.0.9.RELEASE.jar:3.0.9.RELEASE] at
org.thymeleaf.spring5.processor.AbstractSpringFieldTagProcessor.doProcess(AbstractSpringFieldTagProcessor.java:174)
~[thymeleaf-spring5-3.0.9.RELEASE.jar:3.0.9.RELEASE] at
org.thymeleaf.processor.element.AbstractAttributeTagProcessor.doProcess(AbstractAttributeTagProcessor.java:74)
~[thymeleaf-3.0.9.RELEASE.jar:3.0.9.RELEASE] ... 56 common frames
omitted
Here's my codes:
Model File: Expense.java
package com.ksk.expenseapp.model;
import javax.persistence.*;
import java.time.LocalDate;
#Entity
public class Expense {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Integer id;
#Column(name = "date")
private String date;
#Column(name = "expense")
private String expense;
#Column(name = "amount")
private int amount;
//No Arg Construction required by JPA
public Expense() {
}
public Expense(String expense, int amount) {
this.date = LocalDate.now().toString();
this.expense = expense;
this.amount = amount;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getDate() {
return date;
}
public void setDate(String date) {
this.date = date;
}
public String getExpense() {
return expense;
}
public void setExpense(String expense) {
this.expense = expense;
}
public int getAmount() {
return amount;
}
public void setAmount(int amount) {
this.amount = amount;
}
}
Web Controller file
package com.ksk.expenseapp.controller;
import com.ksk.expenseapp.model.Expense;
import com.ksk.expenseapp.repo.ExpenseRepo;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
#Controller
public class WebController {
ExpenseRepo expenseRepo;
#Autowired
public WebController(ExpenseRepo expenseRepo) {
this.expenseRepo = expenseRepo;
}
#RequestMapping("/addExpense")
public String addExpense(){
return "addExpense";
}
#RequestMapping(value = "/save", method = RequestMethod.POST)
public String addNewExpense(#ModelAttribute Expense expense){
expenseRepo.save(expense);
return "addExpense";
}
}
AddExpense html file
<!doctype html>
<html xmlns:th="http://www.thymeleaf.org" lang="en">
<head>
<!-- Required meta tags -->
<meta charset="utf-8"/>
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no"/>
<!-- Bootstrap CSS -->
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css"/>
<title>Hello, world!</title>
</head>
<body>
<h1>Add Expense</h1>
<form th:action="#{/save}" th:object="${expense}" method="post">
<div class="form-group">
<label>Expense</label>
<input type="text" class="form-control" th:field="*{expense}"/>
<label>Amount</label>
<input type="text" class="form-control" th:field="*{amount}"/>
<button class="btn btn-success" type="submit">Submit</button>
</div>
</form>
<script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js" integrity="sha384-ApNbgh9B+Y1QKtv3Rn7W3mgPxhU9K/ScQsAP7hUibX39j7fakFPskvXusvfa0b4Q" crossorigin="anonymous"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js" integrity="sha384-JZR6Spejh4U02d8jOt6vLEHfe/JQGiRRSQQxSfFWpi1MquVdAyjUar5+76PVCmYl" crossorigin="anonymous"></script>
</body>
</html>