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SpringBoot使用Spring-Data-Jpa实现CRUD操作

2019年07月19日  | 移动技术网IT编程  | 我要评论

本文演示了springboot下,实用spring-data-jpa来实现crud操作，视图层采用freemarker

这里我们先把application.properties修改成application.yml 主流格式

内容也改成yml规范格式：

server:
 port: 8888
 context-path: /
 
helloworld: spring boot\u4f60\u597d
 
msyql:
 jdbcname: com.mysql.jdbc.driver
 dburl: jdbc:mysql://localhost:3306/db_diary
 username: root
 password: 123456
 
spring:
 datasource:
  driver-class-name: com.mysql.jdbc.driver
  url: jdbc:mysql://localhost:3306/db_book
  username: root
  password: passwd
 jpa:
  hibernate.ddl-auto: update
  show-sql: true

yml格式有个注意点 冒号后面一定要加个空格

还有我们把context-path改成/方便开发应用

先写一个bookdao接口

package com.hik.dao;

import org.springframework.data.jpa.repository.jparepository;

import com.hik.entity.book;

/**
 * 图书dao接口
 * @author jed
 *
 */
public interface bookdao extends jparepository<book, integer>{

}

要求实现jparepository，jparepository是继承pagingandsortingrepository，pagingandsortingrepository是继承crudrepository。crudrepository实现了实体增删改查操作

/*
 * copyright 2008-2011 the original author or authors.
 *
 * licensed under the apache license, version 2.0 (the "license");
 * you may not use this file except in compliance with the license.
 * you may obtain a copy of the license at
 *
 *  http://www.apache.org/licenses/license-2.0
 *
 * unless required by applicable law or agreed to in writing, software
 * distributed under the license is distributed on an "as is" basis,
 * without warranties or conditions of any kind, either express or implied.
 * see the license for the specific language governing permissions and
 * limitations under the license.
 */
package org.springframework.data.repository;

import java.io.serializable;

/**
 * interface for generic crud operations on a repository for a specific type.
 * 
 * @author oliver gierke
 * @author eberhard wolff
 */
@norepositorybean
public interface crudrepository<t, id extends serializable> extends repository<t, id> {

 /**
  * saves a given entity. use the returned instance for further operations as the save operation might have changed the
  * entity instance completely.
  * 
  * @param entity
  * @return the saved entity
  */
 <s extends t> s save(s entity);

 /**
  * saves all given entities.
  * 
  * @param entities
  * @return the saved entities
  * @throws illegalargumentexception in case the given entity is {@literal null}.
  */
 <s extends t> iterable<s> save(iterable<s> entities);

 /**
  * retrieves an entity by its id.
  * 
  * @param id must not be {@literal null}.
  * @return the entity with the given id or {@literal null} if none found
  * @throws illegalargumentexception if {@code id} is {@literal null}
  */
 t findone(id id);

 /**
  * returns whether an entity with the given id exists.
  * 
  * @param id must not be {@literal null}.
  * @return true if an entity with the given id exists, {@literal false} otherwise
  * @throws illegalargumentexception if {@code id} is {@literal null}
  */
 boolean exists(id id);

 /**
  * returns all instances of the type.
  * 
  * @return all entities
  */
 iterable<t> findall();

 /**
  * returns all instances of the type with the given ids.
  * 
  * @param ids
  * @return
  */
 iterable<t> findall(iterable<id> ids);

 /**
  * returns the number of entities available.
  * 
  * @return the number of entities
  */
 long count();

 /**
  * deletes the entity with the given id.
  * 
  * @param id must not be {@literal null}.
  * @throws illegalargumentexception in case the given {@code id} is {@literal null}
  */
 void delete(id id);

 /**
  * deletes a given entity.
  * 
  * @param entity
  * @throws illegalargumentexception in case the given entity is {@literal null}.
  */
 void delete(t entity);

 /**
  * deletes the given entities.
  * 
  * @param entities
  * @throws illegalargumentexception in case the given {@link iterable} is {@literal null}.
  */
 void delete(iterable<? extends t> entities);

 /**
  * deletes all entities managed by the repository.
  */
 void deleteall();
}

再写一个bookcontroller类

package com.hik.controller;

import javax.annotation.resource;

import org.springframework.stereotype.controller;
import org.springframework.web.bind.annotation.getmapping;
import org.springframework.web.bind.annotation.pathvariable;
import org.springframework.web.bind.annotation.postmapping;
import org.springframework.web.bind.annotation.requestmapping;
import org.springframework.web.bind.annotation.requestmethod;
import org.springframework.web.servlet.modelandview;

import com.hik.dao.bookdao;
import com.hik.entity.book;

/**
 * book控制类
 * @author jed
 *
 */
@controller
@requestmapping("/book")
public class bookcontroller {
 
 @resource
 private bookdao bookdao;
 
 /**
  * 查询所有图书
  * @return
  */
 @requestmapping(value="/list")
 public modelandview list() {
  modelandview mav = new modelandview ();
  mav.addobject("booklist", bookdao.findall());
  mav.setviewname("booklist");
  return mav;
 }

 /**
  * 添加图书
  * @param book
  * @return
  */
 @requestmapping(value="/add", method=requestmethod.post)
 public string add(book book) {
  bookdao.save(book);
  return "forward:/book/list";
 }
 
 @getmapping(value="/preupdate/{id}")
 public modelandview preupdate(@pathvariable("id") integer id) {
  modelandview mav = new modelandview();
  mav.addobject("book", bookdao.getone(id));
  mav.setviewname("bookupdate");
  return mav;
 }
 
 /**
  * 修改图书
  * @param book
  * @return
  */
 @postmapping(value="/update")
 public string update(book book) {
  bookdao.save(book);
  return "forward:/book/list";
 }
 
 /**
  * 删除图书
  * @param id
  * @return
  */
 @requestmapping(value="/delete",method = requestmethod.get)
 public string delete(integer id) {
  bookdao.delete(id);
  return "forward:/book/list";
 }
}

实现了 crud

这里的@getmapping(value="xxx") 类似  @requestmapping(value="xxx",method=requestmethod.get)

以及@postmapping(value="xxx") 类似  @requestmapping(value="xxx",method=requestmethod.post)

booklist.ftl 展示数据

<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>图书管理页面</title>
</head>
<body>
<a href="/bookadd.html" rel="external nofollow" >添加图书</a>
 <table>
  <tr>
   <th>编号</th>
   <th>图书名称</th>
   <th>操作</th>
  </tr>
  <#list booklist as book>  
  <tr>  
   <td>${book.id}</td>  
   <td>${book.bookname}</td> 
   <td>
    <a href="/book/preupdate/${book.id}" rel="external nofollow" >修改</a>
    <a href="/book/delete?id=${book.id}" rel="external nofollow" >删除</a>
   </td>
  </tr> 
  </#list> 
 </table> 
</body>
</html>

bookadd.html 图书添加页面

<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>图书添加页面</title>
</head>
<body>
<form action="book/add" method="post">
 图书名称：<input type="text" name="bookname"/><br/>
 <input type="submit" value="提交"/>
</form>
</body>
</html>

bookupdate.ftl图书修改页面

<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>图书修改页面</title>
</head>
<body>
<form action="/book/update" method="post">
<input type="hidden" name="id" value="${book.id}"/>
 图书名称：<input type="text" name="bookname" value="${book.bookname}"/><br/>
 <input type="submit" value="提交"/>
</form>
</body>
</html>

浏览器请求：http://www.lhsxpumps.com/_localhost:8888/book/list

进入：

点击 “添加图书”：

进入：

我们随便输入名称，点击“提交”，

选择刚才添加的测试图书，进行修改

转发执行到列表页面，然后点“修改”，

进入修改页面，修改下名称，点击“提交”，

选择测试图书，进行删除操作

再次转发到列表页面，我们点击“删除”，

删掉数据后，再次转发到列表页面；

ok完成！

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