一、添加依赖

添加mybatis-spring-boot-starter依赖跟mysql依赖

<!--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>
            <version>5.1.21</version>
        </dependency>

二、数据源配置

在src/main/resources/application.properties中配置数据源信息。

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

三、自定义数据源

1、添加依赖

Spring Boot默认使用tomcat-jdbc数据源，如果你想使用其他的数据源，比如这里使用了阿里巴巴的数据池管理,除了在application.properties配置数据源之外，应该额外添加

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

2、修改Application.java

这样就算自己配置了一个DataSource，Spring Boot会智能地选择我们自己配置的这个DataSource实例。

import com.alibaba.druid.pool.DruidDataSource;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.core.env.Environment;

import javax.sql.DataSource;

@SpringBootApplication
@MapperScan("com.example.demo.mapper")
public class Application {
   public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
   @Autowired
    private Environment env;
   //destroy-method="close"的作用是当数据库连接不使用的时候,就把该连接重新放到数据池中,方便下次使用调用.
    @Bean(destroyMethod =  "close")
    public DataSource dataSource() {
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setUrl(env.getProperty("spring.datasource.url"));
        dataSource.setUsername(env.getProperty("spring.datasource.username"));//用户名
        dataSource.setPassword(env.getProperty("spring.datasource.password"));//密码
        dataSource.setDriverClassName(env.getProperty("spring.datasource.driver-class-name"));
        dataSource.setInitialSize(2);//初始化时建立物理连接的个数
        dataSource.setMaxActive(20);//最大连接池数量
        dataSource.setMinIdle(0);//最小连接池数量
        dataSource.setMaxWait(60000);//获取连接时最大等待时间，单位毫秒。
        dataSource.setValidationQuery("SELECT 1");//用来检测连接是否有效的sql
        dataSource.setTestOnBorrow(false);//申请连接时执行validationQuery检测连接是否有效
        dataSource.setTestWhileIdle(true);//建议配置为true，不影响性能，并且保证安全性。
        dataSource.setPoolPreparedStatements(false);//是否缓存preparedStatement，也就是PSCache
        return dataSource;
    }
}

3、在数据库创建表，提供源数据

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 '作者',
  `title` varchar(100) DEFAULT NULL COMMENT '描述',
  `url` varchar(100) DEFAULT NULL COMMENT '地址链接',
  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,'后端编程','Spring Boot视频教程','http://www.toutiao.com/m1559096720023553/');

四、创建实体类

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

五、Controller层

@Controller
public class HelloController {
    @Autowired
    LearnMapper learnMapper;

    @RequestMapping("hello")
    public ModelAndView hello(HttpServletResponse response) throws IOException {
//        response.getWriter().println("hello");
        LearnResouce learnResouce = new LearnResouce();
        learnResouce.setAuthor("zhangsan");
        learnMapper.add(learnResouce);
        ModelAndView modelAndView = new ModelAndView();
        modelAndView.setViewName("hello");
        modelAndView.addObject("username","zhangsan");
        return modelAndView;
    }

}

六、Mybatis集成

1、编写Dao层

package com.dudu.dao;
@Mapper
@Component
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);
}

2、修改application.properties 配置文件

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

3、添加LearnMapper的映射文件

在src/main/resources目录下新建一个mapper目录，在mapper目录下新建LearnMapper.xml文件。

通过mapper标签中的namespace属性指定对应的dao映射，这里指向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.example.demo.mapper.LearnMapper">
    <resultMap id="baseResultMap" type="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="LearnResouce" >
        INSERT INTO learn_resource (author, title,url) VALUES (#{author}, #{title}, #{url})
    </insert>

    <update id="update" parameterType="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>