springbootのMysqlの接続について

前提・実現したいこと

springbootで会員登録画面を作成しています。
使用しているDBはMysqlです。
DB上のカラムはID,名前,メモです。
会員登録画面で名前とメモのテキストボックスに値を入力して、送信ボタンを押下したんですが、
DBにはIDだけ値が入っており、名前とメモにテキストボックスに入力した値が入っていないのですが、
原因は何になるのでしょうか？
ご回答のほど宜しくお願い致します

エラーメッセージ(修正後)
2016-08-21 21:29:22.614  INFO 1279 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2016-08-21 21:29:23.410  INFO 1279 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
2016-08-21 21:29:23.507  INFO 1279 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http)
2016-08-21 21:29:23.515  INFO 1279 --- [           main] c.t.springboot.SokutakuhaiApplication    : Started SokutakuhaiApplication in 8.004 seconds (JVM running for 8.653)
2016-08-21 21:29:31.213  INFO 1279 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring FrameworkServlet 'dispatcherServlet'
2016-08-21 21:29:31.213  INFO 1279 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : FrameworkServlet 'dispatcherServlet': initialization started
2016-08-21 21:29:31.238  INFO 1279 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : FrameworkServlet 'dispatcherServlet': initialization completed in 25 ms
2016-08-21 21:29:31.335  INFO 1279 --- [nio-8080-exec-1] o.h.h.i.QueryTranslatorFactoryInitiator  : HHH000397: Using ASTQueryTranslatorFactory
2016-08-21 21:29:31.580 ERROR 1279 --- [nio-8080-exec-1] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.orm.jpa.JpaSystemException: No default constructor for entity:  : com.tuyano.springboot.MyDataMongo; nested exception is org.hibernate.InstantiationException: No default constructor for entity:  : com.tuyano.springboot.MyDataMongo] with root cause

org.hibernate.InstantiationException: No default constructor for entity:  : com.tuyano.springboot.MyDataMongo
    at org.hibernate.tuple.PojoInstantiator.instantiate(PojoInstantiator.java:84) ~[hibernate-core-5.0.9.Final.jar:5.0.9.Final]
    at org.hibernate.tuple.PojoInstantiator.instantiate(PojoInstantiator.java:100) ~[hibernate-core-5.0.9.Final.jar:5.0.9.Final]
    at org.hibernate.tuple.entity.AbstractEntityTuplizer.instantiate(AbstractEntityTuplizer.java:631) ~[hibernate-core-5.0.9.Final.jar:5.0.9.Final]
    at org.hibernate.persister.entity.AbstractEntityPersister.instantiate(AbstractEntityPersister.java:4616) ~[hibernate-core-5.0.9.Final.jar:5.0.9.Final]
    at org.hibernate.internal.SessionImpl.instantiate(SessionImpl.java:1470) ~[hibernate-core-5.0.9.Final.jar:5.0.9.Final]
    at org.hibernate.internal.SessionImpl.instantiate(SessionImpl.java:1454) ~[hibernate-core-5.0.9.Final.jar:5.0.9.Final]

・HeloController（修正後）
package com.tuyano.springboot;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.servlet.ModelAndView;

import com.tuyano.springboot.repositories.MyDataMongoRepository;

@Controller
public class HeloController {

@Autowired
MyDataMongoRepository repository;

@RequestMapping(value="/",method=RequestMethod.GET)
public ModelAndView index(ModelAndView mav){
    mav.setViewName("index");
    mav.addObject("title","Find Page");
    mav.addObject("msg","サンプルです");
    Iterable<MyDataMongo> list=repository.findAll();
    mav.addObject("datalist",list);
    System.out.println(mav);
    return mav;
}
@RequestMapping(value="/",method=RequestMethod.POST)

public ModelAndView form(
        @RequestParam("name")String name,
        @RequestParam("memo")String memo,
        ModelAndView mov){
    MyDataMongo mydata =new MyDataMongo(name,memo);
    System.out.println("mydataは"+mydata);
    repository.saveAndFlush(mydata);
    mov =new ModelAndView("redirect:/");
    System.out.println("mov"+mov);
    return mov;
}

@RequestMapping(value="/find",method=RequestMethod.GET)
public ModelAndView find(ModelAndView mav){
    mav.setViewName("find");
    mav.addObject("title","Find Page");
    mav.addObject("msg","サンプルです");
    mav.addObject("value","");
    Iterable<MyDataMongo> list=repository.findAll();
    mav.addObject("datalist",list);
    System.out.println(mav);
    return mav;
}
@RequestMapping(value="/find",method=RequestMethod.POST)
public ModelAndView search(
        @RequestParam("find")String param,
        ModelAndView mav){
    mav.setViewName("find");
    if(param==""){
    mav =new ModelAndView("redirect:/find");
    }else{
        mav.addObject("title","Find Result");
        mav.addObject("msg","["+param+"]の検索結果");
        mav.addObject("value",param);
        List<MyDataMongo> list=repository.findByName(param);
        mav.addObject("dataList",list);
}
return mav;
}
}

・MyDataMongo.java（修正後）
package com.tuyano.springboot;

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="Linefriend")
public class MyDataMongo {
@Id
@GeneratedValue(strategy=GenerationType.AUTO)
@Column
private Long id;

@Column
private String name;
@Column
private String memo;
//private Date date;
public MyDataMongo(String name, String memo) {
    super();
    this.name=name;
    this.memo=memo;
}

//public void setId(Long id){

//    this.id=id;

//}

public Long getId(){

    return id;

}


public String getName(){

    return name;

}





public String getMemo(){

    return memo;

}






}

・index.html
<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head>
<title>top page</title>
<meta http-equiv="Content-Type"
content="text/html" charset="UTF-8"/>
</head>
<body>

   <h1 th:text="#{context.title}">Helo Page</h1>
   <p th:text="${msg}"></p>
   <table>
   <form method="post" action="/">
   <tr><td><label for="name">名前</label></td>
  <td><input type="text" name="name"/></td></tr>
   <tr><td><label for="memo">メモ</label></td>
  <td><textarea name="memo" cols="20" rows="5"></textarea></td></tr> 
  <tr><td></td><td><input type="submit" /></td></tr>
  </form>
  </table>
   <hr />
   <table>
   <tr><th>名前</th><th>メモ</th><th>日時</th></tr>
   <tr th:each="obj :${datalist}">
   <td th:text="${obj.name}"></td>
   <td th:text="${obj.memo}"></td>

   </tr>
   </table>

</body>
</html>

・MyDataMongoRepository.java
package com.tuyano.springboot.repositories;

import java.util.List;

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

import com.tuyano.springboot.MyDataMongo;
@Repository
public interface MyDataMongoRepository extends JpaRepository<MyDataMongo,Long>{
List<MyDataMongo>findByName(String s);
}