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：
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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
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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
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/* * 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 */@norepositorybeanpublic 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
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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
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<!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
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<!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
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<!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！
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持服务器之家。
原文链接：https://www.cnblogs.com/jedjia/p/CRUD.html
