SpringBoot使用Spring-Data-Jpa实现CRUD操作
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://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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