Spring Boot乾貨系列:(九)數據存儲篇-SQL關係型數據庫之MyBatis的使用 | 掘金技術徵文

本來地址:Spring Boot乾貨系列:(九)數據存儲篇-SQL關係型數據庫之MyBatis的使用
博客地址:tengj.top/javascript

前言

上篇咱們介紹了Spring Boot對傳統JdbcTemplate的集成,此次換一下,介紹下Spring Boot中如何集成MyBatis。這裏分別介紹註解方式以及XML方式的整合。喜歡哪一種方式本身選擇。php

正文

項目框架仍是跟上一篇同樣使用Spring Boot的ace後端模板,你能夠基於它來跟着博主一塊兒來調整代碼,若是沒看過上一篇,那就下載本篇源碼研究吧。html

跟上篇同樣先添加基礎的依賴和數據源。java

添加依賴

這裏須要添加mybatis-spring-boot-starter依賴跟mysql依賴mysql

<!--最新版本,匹配spring Boot1.5 or higher-->
 <dependency>
     <groupId>org.mybatis.spring.boot</groupId>
     <artifactId>mybatis-spring-boot-starter</artifactId>
     <version>1.3.0</version>
 </dependency>

<dependency>
     <groupId>mysql</groupId>
     <artifactId>mysql-connector-java</artifactId>
 </dependency>複製代碼

這裏不引入spring-boot-starter-jdbc依賴,是因爲mybatis-spring-boot-starter中已經包含了此依賴。git

博主開始整理的時候發現mybatis-spring-boot-starter有新版本了,這裏就集成最新的,匹配Spring Boot1.5版本。
github

MyBatis-Spring-Boot-Starter依賴將會提供以下:spring

  • 自動檢測現有的DataSource
  • 將建立並註冊SqlSessionFactory的實例,該實例使用SqlSessionFactoryBean將該DataSource做爲輸入進行傳遞
  • 將建立並註冊從SqlSessionFactory中獲取的SqlSessionTemplate的實例。
  • 自動掃描您的mappers,將它們連接到SqlSessionTemplate並將其註冊到Spring上下文,以便將它們注入到您的bean中。

就是說,使用了該Starter以後,只須要定義一個DataSource便可(application.properties中可配置),它會自動建立使用該DataSource的SqlSessionFactoryBean以及SqlSessionTemplate。會自動掃描你的Mappers,鏈接到SqlSessionTemplate,並註冊到Spring上下文中。sql

數據源配置

在src/main/resources/application.properties中配置數據源信息。數據庫

spring.datasource.url = jdbc:mysql://localhost:3306/spring?useUnicode=true&characterEncoding=utf-8
 spring.datasource.username = root
 spring.datasource.password = root
 spring.datasource.driver-class-name = com.mysql.jdbc.Driver複製代碼

自定義數據源

Spring Boot默認使用tomcat-jdbc數據源,若是你想使用其餘的數據源,好比這裏使用了阿里巴巴的數據池管理,除了在application.properties配置數據源以外,你應該額外添加如下依賴:

<dependency>
     <groupId>com.alibaba</groupId>
     <artifactId>druid</artifactId>
     <version>1.0.19</version>
 </dependency>複製代碼

修改Application.java

@SpringBootApplication
 public class Application {
    public static void main(String[] args) {
         SpringApplication.run(Application.class, args);
     }
    @Autowired
     private Environment env;
    //destroy-method="close"的做用是當數據庫鏈接不使用的時候,就把該鏈接從新放到數據池中,方便下次使用調用.
     @Bean(destroyMethod =  "close")
     public DataSource dataSource() {
         DruidDataSource dataSource = new DruidDataSource();
         dataSource.setUrl(env.getProperty("spring.datasource.url"));
         dataSource.setUsername(env.getProperty("spring.datasource.username"));//用戶名
         dataSource.setPassword(env.getProperty("spring.datasource.password"));//密碼
         dataSource.setDriverClassName(env.getProperty("spring.datasource.driver-class-name"));
         dataSource.setInitialSize(2);//初始化時創建物理鏈接的個數
         dataSource.setMaxActive(20);//最大鏈接池數量
         dataSource.setMinIdle(0);//最小鏈接池數量
         dataSource.setMaxWait(60000);//獲取鏈接時最大等待時間,單位毫秒。
         dataSource.setValidationQuery("SELECT 1");//用來檢測鏈接是否有效的sql
         dataSource.setTestOnBorrow(false);//申請鏈接時執行validationQuery檢測鏈接是否有效
         dataSource.setTestWhileIdle(true);//建議配置爲true,不影響性能,而且保證安全性。
         dataSource.setPoolPreparedStatements(false);//是否緩存preparedStatement,也就是PSCache
         return dataSource;
     }
 }複製代碼

ok這樣就算本身配置了一個DataSource,Spring Boot會智能地選擇咱們本身配置的這個DataSource實例。

腳本初始化

CREATE DATABASE /*!32312 IF NOT EXISTS*/`spring` /*!40100 DEFAULT CHARACTER SET utf8 */;
 USE `spring`;
 DROP TABLE IF EXISTS `learn_resource`;

CREATE TABLE `learn_resource` (
   `id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT 'ID',
   `author` varchar(20) DEFAULT NULL COMMENT '做者',
   `title` varchar(100) DEFAULT NULL COMMENT '描述',
   `url` varchar(100) DEFAULT NULL COMMENT '地址連接',
   PRIMARY KEY (`id`)
 ) ENGINE=MyISAM AUTO_INCREMENT=1029 DEFAULT CHARSET=utf8;

insert into `learn_resource`(`id`,`author`,`title`,`url`) values (999,'官方SpriongBoot例子','官方SpriongBoot例子','https://github.com/spring-projects/spring-boot/tree/master/spring-boot-samples');
 insert into `learn_resource`(`id`,`author`,`title`,`url`) values (1000,'龍果學院','Spring Boot 教程系列學習','http://www.roncoo.com/article/detail/124661');
 insert into `learn_resource`(`id`,`author`,`title`,`url`) values (1001,'嘟嘟MD獨立博客','Spring Boot乾貨系列','http://tengj.top/');
 insert into `learn_resource`(`id`,`author`,`title`,`url`) values (1002,'後端編程嘟','Spring Boot視頻教程','http://www.toutiao.com/m1559096720023553/');複製代碼

註解方式跟XML配置方式共同的模塊編碼

不論是註解方式仍是XML配置的方式,如下代碼模塊都是同樣的

實體對象

public class LearnResouce {
     private Long id;
     private String author;
     private String title;
     private String url;
     // SET和GET方法
 }複製代碼

Controller層

/** 教程頁面 * Created by tengj on 2017/3/13. */
 @Controller
 @RequestMapping("/learn")
 public class LearnController {
     @Autowired
     private LearnService learnService;
     private Logger logger = LoggerFactory.getLogger(this.getClass());

    @RequestMapping("")
     public String learn(){
         return "learn-resource";
     }

    @RequestMapping(value = "/queryLeanList",method = RequestMethod.POST,produces="application/json;charset=UTF-8")
     @ResponseBody
     public void queryLearnList(HttpServletRequest request ,HttpServletResponse response){
         String page = request.getParameter("page"); // 取得當前頁數,注意這是jqgrid自身的參數
         String rows = request.getParameter("rows"); // 取得每頁顯示行數,,注意這是jqgrid自身的參數
         String author = request.getParameter("author");
         String title = request.getParameter("title");
         Map<String,Object> params = new HashMap<String,Object>();
         params.put("page", page);
         params.put("rows", rows);
         params.put("author", author);
         params.put("title", title);
         List<LearnResouce> learnList=learnService.queryLearnResouceList(params);
         PageInfo<LearnResouce> pageInfo =new PageInfo<LearnResouce>(learnList);
         JSONObject jo=new JSONObject();
         jo.put("rows", learnList);
         jo.put("total", pageInfo.getPages());//總頁數
         jo.put("records",pageInfo.getTotal());//查詢出的總記錄數
         ServletUtil.createSuccessResponse(200, jo, response);
     }
     /** * 新添教程 * @param request * @param response */
     @RequestMapping(value = "/add",method = RequestMethod.POST)
     public void addLearn(HttpServletRequest request , HttpServletResponse response){
         JSONObject result=new JSONObject();
         String author = request.getParameter("author");
         String title = request.getParameter("title");
         String url = request.getParameter("url");
         if(StringUtil.isNull(author)){
             result.put("message","做者不能爲空!");
             result.put("flag",false);
             ServletUtil.createSuccessResponse(200, result, response);
             return;
         }
         if(StringUtil.isNull(title)){
             result.put("message","教程名稱不能爲空!");
             result.put("flag",false);
             ServletUtil.createSuccessResponse(200, result, response);
             return;
         }
         if(StringUtil.isNull(url)){
             result.put("message","地址不能爲空!");
             result.put("flag",false);
             ServletUtil.createSuccessResponse(200, result, response);
             return;
         }
         LearnResouce learnResouce = new LearnResouce();
         learnResouce.setAuthor(author);
         learnResouce.setTitle(title);
         learnResouce.setUrl(url);
         int index=learnService.add(learnResouce);
         if(index>0){
             result.put("message","教程信息添加成功!");
             result.put("flag",true);
         }else{
             result.put("message","教程信息添加失敗!");
             result.put("flag",false);
         }
         ServletUtil.createSuccessResponse(200, result, response);
     }
     /** * 修改教程 * @param request * @param response */
     @RequestMapping(value = "/update",method = RequestMethod.POST)
     public void updateLearn(HttpServletRequest request , HttpServletResponse response){
         JSONObject result=new JSONObject();
         String id = request.getParameter("id");
         LearnResouce learnResouce=learnService.queryLearnResouceById(Long.valueOf(id));
         String author = request.getParameter("author");
         String title = request.getParameter("title");
         String url = request.getParameter("url");
         if(StringUtil.isNull(author)){
             result.put("message","做者不能爲空!");
             result.put("flag",false);
             ServletUtil.createSuccessResponse(200, result, response);
             return;
         }
         if(StringUtil.isNull(title)){
             result.put("message","教程名稱不能爲空!");
             result.put("flag",false);
             ServletUtil.createSuccessResponse(200, result, response);
             return;
         }
         if(StringUtil.isNull(url)){
             result.put("message","地址不能爲空!");
             result.put("flag",false);
             ServletUtil.createSuccessResponse(200, result, response);
             return;
         }
         learnResouce.setAuthor(author);
         learnResouce.setTitle(title);
         learnResouce.setUrl(url);
         int index=learnService.update(learnResouce);
         System.out.println("修改結果="+index);
         if(index>0){
             result.put("message","教程信息修改爲功!");
             result.put("flag",true);
         }else{
             result.put("message","教程信息修改失敗!");
             result.put("flag",false);
         }
         ServletUtil.createSuccessResponse(200, result, response);
     }
     /** * 刪除教程 * @param request * @param response */
     @RequestMapping(value="/delete",method = RequestMethod.POST)
     @ResponseBody
     public void deleteUser(HttpServletRequest request ,HttpServletResponse response){
         String ids = request.getParameter("ids");
         System.out.println("ids==="+ids);
         JSONObject result = new JSONObject();
         //刪除操做
         int index = learnService.deleteByIds(ids.split(","));
         if(index>0){
             result.put("message","教程信息刪除成功!");
             result.put("flag",true);
         }else{
             result.put("message","教程信息刪除失敗!");
             result.put("flag",false);
         }
         ServletUtil.createSuccessResponse(200, result, response);
     }
 }複製代碼

Service層

package com.dudu.service;
 public interface LearnService {
     int add(LearnResouce learnResouce);
     int update(LearnResouce learnResouce);
     int deleteByIds(String[] ids);
     LearnResouce queryLearnResouceById(Long learnResouce);
     List<LearnResouce> queryLearnResouceList(Map<String, Object> params);
 }複製代碼

實現類

package com.dudu.service.impl;

/** * Created by tengj on 2017/4/7. */
 @Service
 public class LearnServiceImpl implements LearnService {

    @Autowired
     LearnMapper learnMapper;
     @Override
     public int add(LearnResouce learnResouce) {
         return this.learnMapper.add(learnResouce);
     }

    @Override
     public int update(LearnResouce learnResouce) {
         return this.learnMapper.update(learnResouce);
     }

    @Override
     public int deleteByIds(String[] ids) {
         return this.learnMapper.deleteByIds(ids);
     }

    @Override
     public LearnResouce queryLearnResouceById(Long id) {
         return this.learnMapper.queryLearnResouceById(id);
     }

    @Override
     public List<LearnResouce> queryLearnResouceList(Map<String,Object> params) {
         PageHelper.startPage(Integer.parseInt(params.get("page").toString()), Integer.parseInt(params.get("rows").toString()));
         return this.learnMapper.queryLearnResouceList(params);
     }
 }複製代碼

Mybatis集成

接下來,咱們分別來介紹下註解方式以及XML配置方式。

方案一:註解方式

Mybatis註解的方式好簡單,只要定義一個dao接口,而後sql語句經過註解寫在接口方法上。最後給這個接口添加@Mapper註解或者在啓動類上添加@MapperScan("com.dudu.dao")註解都行。

以下:

package com.dudu.dao;
 /** * Created by tengj on 2017/4/22. * Component註解不添加也沒事,只是不加service那邊引入LearnMapper會有錯誤提示,但不影響 */
 @Component
 @Mapper
 public interface LearnMapper {
     @Insert("insert into learn_resource(author, title,url) values(#{author},#{title},#{url})")
     int add(LearnResouce learnResouce);

    @Update("update learn_resource set author=#{author},title=#{title},url=#{url} where id = #{id}")
     int update(LearnResouce learnResouce);

    @DeleteProvider(type = LearnSqlBuilder.class, method = "deleteByids")
     int deleteByIds(@Param("ids") String[] ids);

    @Select("select * from learn_resource where id = #{id}")
     @Results(id = "learnMap", value = {
             @Result(column = "id", property = "id", javaType = Long.class),
             @Result(property = "author", column = "author", javaType = String.class),
             @Result(property = "title", column = "title", javaType = String.class)
     })
     LearnResouce queryLearnResouceById(@Param("id") Long id);

    @SelectProvider(type = LearnSqlBuilder.class, method = "queryLearnResouceByParams")
     List<LearnResouce> queryLearnResouceList(Map<String, Object> params);

    class LearnSqlBuilder {
         public String queryLearnResouceByParams(final Map<String, Object> params) {
             StringBuffer sql =new StringBuffer();
             sql.append("select * from learn_resource where 1=1");
             if(!StringUtil.isNull((String)params.get("author"))){
                 sql.append(" and author like '%").append((String)params.get("author")).append("%'");
             }
             if(!StringUtil.isNull((String)params.get("title"))){
                 sql.append(" and title like '%").append((String)params.get("title")).append("%'");
             }
             System.out.println("查詢sql=="+sql.toString());
             return sql.toString();
         }

        //刪除的方法
         public String deleteByids(@Param("ids") final String[] ids){
             StringBuffer sql =new StringBuffer();
             sql.append("DELETE FROM learn_resource WHERE id in(");
             for (int i=0;i<ids.length;i++){
                 if(i==ids.length-1){
                     sql.append(ids[i]);
                 }else{
                     sql.append(ids[i]).append(",");
                 }
             }
             sql.append(")");
             return sql.toString();
         }
     }
 }複製代碼

須要注意的是,簡單的語句只須要使用@Insert、@Update、@Delete、@Select這4個註解便可,可是有些複雜點須要動態SQL語句,就好比上面方法中根據查詢條件是否有值來動態添加sql的,就須要使用@InsertProvider、@UpdateProvider、@DeleteProvider、@SelectProvider等註解。

這些可選的 SQL 註解容許你指定一個類名和一個方法在執行時來返回運行 容許建立動態 的 SQL。 基於執行的映射語句, MyBatis 會實例化這個類,而後執行由 provider 指定的方法. 該方法能夠有選擇地接受參數對象.(In MyBatis 3.4 or later, it's allow multiple parameters) 屬性: type,method。type 屬性是類。method 屬性是方法名。 注意: 這節以後是對 類的 討論,它能夠幫助你以乾淨,容於閱讀 的方式來構建動態 SQL。

方案二:XML配置方式

xml配置方式保持映射文件的老傳統,優化主要體如今不須要實現dao的是實現層,系統會自動根據方法名在映射文件中找對應的sql,具體操做以下:

編寫Dao層的代碼
新建LearnMapper接口,無需具體實現類。

package com.dudu.dao;
 @Mapper
 public interface LearnMapper {
     int add(LearnResouce learnResouce);
     int update(LearnResouce learnResouce);
     int deleteByIds(String[] ids);
     LearnResouce queryLearnResouceById(Long id);
     public List<LearnResouce> queryLearnResouceList(Map<String, Object> params);
 }複製代碼

修改application.properties 配置文件

#指定bean所在包
 mybatis.type-aliases-package=com.dudu.domain
 #指定映射文件
 mybatis.mapperLocations=classpath:mapper/*.xml複製代碼

添加LearnMapper的映射文件
在src/main/resources目錄下新建一個mapper目錄,在mapper目錄下新建LearnMapper.xml文件。

經過mapper標籤中的namespace屬性指定對應的dao映射,這裏指向LearnMapper。

<?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
 <mapper namespace="com.dudu.dao.LearnMapper">
   <resultMap id="baseResultMap" type="com.dudu.domain.LearnResouce">
     <id column="id" property="id" jdbcType="BIGINT" />
     <result column="author" property="author" jdbcType="VARCHAR"/>
     <result column="title" property="title" jdbcType="VARCHAR"/>
     <result column="url" property="url" jdbcType="VARCHAR"/>
   </resultMap>

  <sql id="baseColumnList" >
     id, author, title,url
   </sql>

  <select id="queryLearnResouceList" resultMap="baseResultMap" parameterType="java.util.HashMap">
     select
     <include refid="baseColumnList" />
     from learn_resource
     <where>
       1 = 1
       <if test="author!= null and author !=''">
         AND author like CONCAT(CONCAT('%',#{author,jdbcType=VARCHAR}),'%')
       </if>
       <if test="title != null and title !=''">
         AND title like  CONCAT(CONCAT('%',#{title,jdbcType=VARCHAR}),'%')
       </if>

    </where>
   </select>

  <select id="queryLearnResouceById" resultMap="baseResultMap" parameterType="java.lang.Long">
     SELECT
     <include refid="baseColumnList" />
     FROM learn_resource
     WHERE id = #{id}
   </select>

  <insert id="add" parameterType="com.dudu.domain.LearnResouce" >
     INSERT INTO learn_resource (author, title,url) VALUES (#{author}, #{title}, #{url})
   </insert>

  <update id="update" parameterType="com.dudu.domain.LearnResouce" >
     UPDATE learn_resource SET author = #{author},title = #{title},url = #{url} WHERE id = #{id}
   </update>

  <delete id="deleteByIds" parameterType="java.lang.String" >
     DELETE FROM learn_resource WHERE id in
     <foreach item="idItem" collection="array" open="(" separator="," close=")">
       #{idItem}
     </foreach>
   </delete>
 </mapper>複製代碼

更多mybatis數據訪問操做的使用請參考:mybatis官方中文參考文檔

分頁插件

上面我有使用到物理分頁插件pagehelper,用法還算簡單,配置以下
pom.xml中添加依賴

<dependency>
     <groupId>com.github.pagehelper</groupId>
     <artifactId>pagehelper-spring-boot-starter</artifactId>
     <version>1.1.0</version>
 </dependency>複製代碼

而後你只需在查詢list以前使用PageHelper.startPage(int pageNum, int pageSize)方法便可。pageNum是第幾頁,pageSize是每頁多少條。

@Override
     public List<LearnResouce> queryLearnResouceList(Map<String,Object> params) {
         PageHelper.startPage(Integer.parseInt(params.get("page").toString()), Integer.parseInt(params.get("rows").toString()));
         return this.learnMapper.queryLearnResouceList(params);
     }複製代碼

分頁插件PageHelper項目地址: github.com/pagehelper/…

最終項目效果以下,增刪改查分頁一個都很多:

總結

到此爲止,Spring Boot與Mybatis的初步整合就完成了,項目不只整合了bootstrap模板框架,還包含了登陸、攔截器、日誌框架logback等前面介紹的功能。麻雀雖小,五臟俱全。

想要查看更多Spring Boot乾貨教程,可前往:Spring Boot乾貨系列總綱

源碼下載

( ̄︶ ̄)↗[相關示例完整代碼]

  • chapter9==》Spring Boot乾貨系列:(九)數據存儲篇-SQL關係型數據庫之MyBatis-註解方式
  • chapter9-2==》Spring Boot乾貨系列:(九)數據存儲篇-SQL關係型數據庫之MyBatis-XML配置方式

想要ace模板源碼的話,在博主公衆號(javaLearn)回覆關鍵字:ace

一直以爲本身寫的不是技術,而是情懷,一篇篇文章是本身這一路走來的痕跡。靠專業技能的成功是最具可複製性的,但願個人這條路能讓你少走彎路,但願我能幫你抹去知識的蒙塵,但願我能幫你理清知識的脈絡,但願將來技術之巔上有你也有我!

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