Java Spring Boot エラーの解決

Question

前提・実現したいこと

Spring Boot を用いて ToDo アプリケーションを作成しています.
save を実行しようとすると以下のエラーが出てしまい, save ができない状態です.
今回 save をしようとした文字は a です.
どこが間違っているのかご指摘いただけるとありがたいです. よろしくお願いします.
また, YouTube の　https://www.youtube.com/watch?v=qZs0885Mdm0 を参考にアプリケーションを作成しています.
文字数の関係でソースコードの一部を抜粋しています.

発生している問題・エラーメッセージ

This application has no explicit mapping for /error, so you are seeing this as a fallback.

Thu Jul 25 22:41:29 JST 2019
There was an unexpected error (type=Bad Request, status=400).
Failed to convert value of type 'java.lang.String' to required type 'com.example.ToDoList.model.ToDo'; nested exception is org.springframework.core.convert.ConversionFailedException: Failed to convert from type [java.lang.String] to type [java.lang.Long] for value 'a'; nested exception is java.lang.NumberFormatException: For input string: "a"
org.springframework.beans.TypeMismatchException: Failed to convert value of type 'java.lang.String' to required type 'com.example.ToDoList.model.ToDo'; nested exception is org.springframework.core.convert.ConversionFailedException: Failed to convert from type [java.lang.String] to type [java.lang.Long] for value 'a'; nested exception is java.lang.NumberFormatException: For input string: "a"

該当のソースコード

Service Implements

package com.example.ToDoList.service.impl;

import java.util.Date;
import java.util.List;
import java.util.Optional;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import com.example.ToDoList.model.ToDo;
import com.example.ToDoList.repository.ToDoRepository;
import com.example.ToDoList.service.ToDoService;

@Service
@Transactional
public class ToDoServiceImpl implements ToDoService{
	
	@Autowired private ToDoRepository toDoRepository;

	@Override
	public List<ToDo> getAllToDos() {
		return (List<ToDo>) toDoRepository.findAll();
	}

	@Override
	public ToDo save(ToDo toDo) {
		toDo.setCreatedDate(new Date());
		return toDoRepository.save(toDo);
	}

	@Override
	public ToDo findById(Long id) {
		Optional<ToDo> toDo = toDoRepository.findById(id);
		if (toDo.isPresent()) {
			return toDo.get();
		} else {
			return null;
		}
	}

}

Model

package com.example.ToDoList.model;

import java.io.Serializable;
import java.util.Date;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name="toDo")
public class ToDo implements Serializable {
	
	/**
	 * 
	 */
	private static final long serialVersionUID = -269687929538344451L;
	@Id
	@GeneratedValue(strategy=GenerationType.AUTO)
	@Column(name="id")
	private Long id;
	@Column(name="to_do")
	private String toDo;
	@Column(name="dead_line")
	private Date deadLine;
	@Column(name="created_date")
	private Date createdDate;
	@Column(name="updated_date")
	private Date updatedDate;
	
	public Long getId() {
		return id;
	}
	
	public void setId(Long id) {
		this.id = id;
	}
	
	public String getToDo() {
		return toDo;
	}
	
	public void setToDo(String toDo) {
		this.toDo = toDo;
	}
	
	public Date getCreatedDate() {
		return createdDate;
	}
	
	public void setCreatedDate(Date createdDate) {
		this.createdDate = createdDate;
	}
	
}

Repository

package com.example.ToDoList.repository;

import org.springframework.data.repository.CrudRepository;
import org.springframework.stereotype.Repository;

import com.example.ToDoList.model.ToDo;

@Repository
public interface ToDoRepository extends CrudRepository<ToDo, Long>{

}

Controller

package com.example.ToDoList.controller;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.servlet.mvc.support.RedirectAttributes;

import com.example.ToDoList.model.ToDo;
import com.example.ToDoList.service.ToDoService;

@Controller
public class ToDoController {
	@Autowired private ToDoService toDoService;
	
	@GetMapping("/")
	public String toDos(Model model) {
		List<ToDo> toDos = toDoService.getAllToDos();
		model.addAttribute("toDos", toDos);
		model.addAttribute("toDo", new ToDo());
		model.addAttribute("title", "ToDos");
		model.addAttribute("isAdd", true);
		return "view/toDos";
	}
	
	@PostMapping(value="/save")
	public String save(@ModelAttribute ToDo toDo, RedirectAttributes redirectAttributes, Model model) {
		ToDo dbToDo = toDoService.save(toDo);
		if (dbToDo!=null) {
			redirectAttributes.addFlashAttribute("successmessage", "ToDo is saved succesfully");
			return "redirect:/";
		} else {
			model.addAttribute("errormessage", "ToDo is not saved, Please try again");
			model.addAttribute("todo", toDo);
			return "view/toDos";
		}
	}
	
	@GetMapping(value="/getToDo/{id}")
	public String getToDo(@PathVariable Long id, Model model) {
		ToDo toDo = toDoService.findById(id);
		List<ToDo> toDos = toDoService.getAllToDos();
		model.addAttribute("toDos", toDos);
		model.addAttribute("toDo", toDo);
		model.addAttribute("title", "Edit ToDos");
		model.addAttribute("isAdd", false);
		return "view/toDos";
	}
	
	@PostMapping(value="/update")
	public String update(@ModelAttribute ToDo toDo, RedirectAttributes redirectAttributes, Model model) {
		ToDo dbToDo = toDoService.update(toDo);
		if (dbToDo != null) {
			redirectAttributes.addFlashAttribute("successmessage", "ToDo is updated succesfully");
			return "redirect:/";
		} else {
			model.addAttribute("errormessage", "ToDo is not updated, Please try again");
			model.addAttribute("toDo", toDo);
			return "view/toDos";
		}
	}
}

HTML

<body>
<div class="container-fluid">
<div class="row">
<div class="col-md-12">
<h2>ToDo Form</h2>
<div class="alert alert-success" th:if="${successmessage}">
  <a href="#" class="close" data-dismiss="alert" arial-label="close">&times;</a>
  <strong th:text=${successmessage}></strong>
</div>
<div class="alert alert-warning" th:if="${errormessage}">
  <a href="#" class="close" data-dismiss="alert" arial-label="close">&times;</a>
  <strong th:text=${errormessage}></strong>
</div>
<form action="#" th:action="@{${isAdd}?'/save':'/update'}" th:object="${toDo}" method="post">
<div class="form-group">
<input type="text" class="form-control" id="toDo" placeholder="ToDo" th:field="*{toDo}">
</div>
<div class="form-group">
<input type="text" class="form-control" id="deadLine" placeholder="Dead Line" th:field="*{deadLine}">
</div>
<input type="hidden" class="form-control" th:field="*{id}">
<button type="submit" class="btn btn-primary" th:text="${isAdd}?'Save':'Update'">Submit</button>
</form>
</div>

<div class="col-md-12">
<h2>All ToDos</h2>
<div style="margin-top:10px">
<table id="todotable" class="table table-striped table-bordered" style="width:100%">
<thead>
<tr>
 <th>ToDo</th>
 <th>Action</th>
</tr>
</thead>
<tbody>
<tr th:each="toDo: ${toDos}">
<td th:text="${toDo.toDoName}"></td>
<td>
  <a th:href="@{'/getToDo/' + ${toDo.id}}"><i class="fa fa-edit" style="font-size: 21px;"></i></a>
  <a href="javascript:void(0)" class="confirm-delete" th:attr="data-id=${toDo.id}, data-name=${toDo.toDoName}">
  <i class="fa fa-trash" style="font-size: 21px;color:red;"></i></a>
</td>

</tr>
</tbody>
</table>
</div>
</div>

</div>
</div>

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js"></script>
<script src="https://cdn.datatables.net/1.10.19/js/dataTables.bootstrap4.min.js"></script>
<script src="https://cdn.datatables.net/1.10.19/js/jquery.dataTables.min.js"></script>
<script type="text/javascript">
$("#toDotable").dataTable();
$(".confirm-delete").on('click', function(e){
	e,preventDefault();
	var id = $(this),data('id');
	var name = $(this).data('name');
	$("#modal-name").html(name);
	$('#idModalLink').attr('href', '/deleteToDo/'+id);
	$('#toDoModal').modal('show');
})
</script>

</body>
</html>

Comments

[moootoko]

テンプレートのHTML内で
<tr th:each="toDo: ${toDos}">
<td th:text="${toDo.toDoName}"></td>
とありますが、
th:eachのtoDoにはList<ToDo>リストから取り出したToDoオブジェクトが入っていると思います。
しかしToDoオブジェクトにはtoDoNameが定義されていませんが、それは大丈夫なのでしょうか。

Answer 1

    @Column(name="to_do")
    private String toDo;

ToDoクラスのプロパティとしてtodoがあるので、上手くパースできてないのかもしれません。
カラム名も変更になりますが無難にtitleなどに変更してみるのはどうでしょう?