SpringBoot使用druid数据源整合mybatis(配置文件版)并实现增删改查（源码）（一个简单的例子）(没有使用逆向工程)

第一步：
导入依赖：

 <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.1</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.8</version>
        </dependency>

第二步：配置数据源application.yml文件

spring:
  datasource:
    username: xxx
    password: xxx
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://xxx.xxx.xxx.xxx:3306/xxx?characterEncoding=utf-8&serverTimezone=UTC
    type: com.alibaba.druid.pool.DruidDataSource

    initialSize: 5
    minIdle: 5
    maxActive: 20
    maxWait: 60000
    timeBetweenEvictionRunsMillis: 60000
    minEvictableIdleTimeMillis: 300000
    validationQuery: SELECT 1 FROM DUAL
    testWhileIdle: true
    testOnBorrow: false
    testOnReturn: false
    poolPreparedStatements: true

    filters: stat,wall,log4j
    maxPoolPreparedStatementPerConnectionSize: 20
    useGlobalDataSourceStat: true
    connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=500
    initialization-mode: always

第三步：编写druid数据源后台监控

package com.haihai.springbootmybatistest02.config;

import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.support.http.StatViewServlet;
import com.alibaba.druid.support.http.WebStatFilter;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import javax.sql.DataSource;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;

@Configuration
public class DruidConfig {

    //注入一个DruidDataSource数据源bean
    @ConfigurationProperties(prefix = "spring.datasource")
    @Bean
    public DataSource druid(){
        return new DruidDataSource();
    }

    @Bean
    //配置一个管理后台的servlet
    public ServletRegistrationBean statViewServlet(){
        ServletRegistrationBean bean=new ServletRegistrationBean(new StatViewServlet(),"/druid/*");

        Map<String,String> initParams=new HashMap<>();
        initParams.put("loginUsername","admin");
        initParams.put("loginPassword","123456");
        initParams.put("allow","");

        bean.setInitParameters(initParams);
        return bean;
    }

    @Bean
    //配置一个web监控的filter
    public FilterRegistrationBean webStatFilter(){
        FilterRegistrationBean bean=new FilterRegistrationBean();
        bean.setFilter(new WebStatFilter());
        Map<String,String> initParams=new HashMap<>();
        initParams.put("exclusions","*.js,*.css,/druid/*");


        bean.setInitParameters(initParams);
        bean.setUrlPatterns(Arrays.asList("/*"));
        return  bean;
    }
}

第四步：编写mybatis的配置文件

这些配置文件可以去官网抄写，然后修改参数,也可以用下面我的配置文件再修改参数。

这里是官方文档
https://blog.csdn.net/weixin_42336011/article/details/104439172

mybatis-config.xml文件

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>

</configuration>

EmpMapper.xml文件

<?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">
    <!--namespace写你的mapper接口的全类名-->
<mapper namespace="com.haihai.springbootmybatistest02.mapper.EmpMapper">
        <!--//根据id查出相应内容
    Emp getEmpById(int eid);-->
    <select id="getEmpById" resultType="com.haihai.springbootmybatistest02.bean.Emp">
        select * from emp where eid=#{eid}
    </select>

    <!--//增加一个记录
    int insert(Emp emp);-->
    <insert id="insert">
        insert into emp values (#{eid},#{ename})
    </insert>

   <!-- //删除一个记录
    int delete(int eid);-->
    <delete id="delete">
        delete from emp where eid=#{eid}
    </delete>

    <!--//修改一个记录
    int update(Emp emp);-->
    <update id="update">
        update emp set ename=#{ename} where eid=#{eid}
    </update>
</mapper>

第五步：在全局配置文件application.yml中配置mybatis的文件路径

并且在SpringBoot启动类中添加mapper的扫描，如下图

也可以在mapper接口上面写mapper注解(上面和这里二选一就可以了)，如下图：

第六步：编写controller测试

import com.haihai.springbootmybatistest02.bean.Emp;
import com.haihai.springbootmybatistest02.mapper.EmpMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;


@Controller
public class EmpController {

    @Autowired
    EmpMapper empMapper;

    //查询
    @ResponseBody
    @RequestMapping("/emp/{eid}")
    public Emp getEmpById(@PathVariable("eid") int eid){
        return empMapper.getEmpById(eid);
    }
    //当测试增删改的时候要将最上面的Controller注解换成RestController
	@RequestMapping("/empinsert")
    public void insertInto(){
        Emp emp=new Emp(199,"第十三个");
        empMapper.insert(emp);

    }

    @RequestMapping("/deleteh")
    public void delete(){
        //Emp emp=new Emp(18,"第十三个");
        int num=empMapper.delete(1);
        System.out.println(num);
    }

    @RequestMapping("/updateh")
    public void update(){
        Emp emp=new Emp(18,"第1个");
        int num=empMapper.update(emp);
        System.out.println(num);
    }
}

总结：注解版与配置文件版的简单对比

注解版使用起来会比配置版简单，快速。在实现简单的sql语句时（就是简单的增删查改），比较有优势。整合配置文件版本的mybatis，过程会稍微复杂一些，但是在处理复杂sql语句，比如动态sql的时候（也就是可以根据传入的字段（可多可少）进行相应的查询或者其他操作），会比较有优势。

如果想要查看SpringBoot整合注解版的mybatis可以去下面的链接，下面是超链接，直接点击就可以了。
亲，点我，点我查看注解版