SpringBoot学习笔记（6）Mybatis整合

简介

这篇文章主要介绍SpringBoot集成Mybatis，数据库连接池使用alibaba的druid。SpringBoot微服框架虽然可以支持集成mybaits后不使用xml文件来写sql，但是习惯了xml配置sql的也可以用xml来实现。实现上具体用什么方式并不重要，主要是搭建一遍，对框架的运转就比较清晰。本博客还是用xml的方式来实现Mybatis的sql编写，不用注解方式。

pom文件配置

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.0.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.meng</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>db_demo</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>


        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</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>
        <!--自定义连接池-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.10</version>
        </dependency>

        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </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>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

SpringBoot配置文件

spring:
  datasource:
    username: root
    password: 123456
    url: jdbc:mysql://192.168.0.157:3306/db1
    driver-class-name: com.mysql.cj.jdbc.Driver
    type: com.alibaba.druid.pool.DruidDataSource

    #   数据源其他配置
    #初始化大小，最小，最大
    initialSize: 5
    minIdle: 5
    maxActive: 20
    # 配置获取连接等待超时的时间
    maxWait: 60000
    # 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒
    timeBetweenEvictionRunsMillis: 60000
    # 配置一个连接在池中最小生存的时间，单位是毫秒
    minEvictableIdleTimeMillis: 300000
    validationQuery: SELECT 1 FROM DUAL
    testWhileIdle: true
    testOnBorrow: false
    testOnReturn: false
    poolPreparedStatements: true
    #   配置监控统计拦截的filters，去掉后监控界面sql无法统计，'wall'用于防火墙
    filters: stat,wall,log4j
    maxPoolPreparedStatementPerConnectionSize: 20
    useGlobalDataSourceStat: true
    connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=500
mybatis:
  config-location: classpath:mybatis/mybatis-config.xml
  mapper-locations: classpath:mybatis/mapper/*.xml

 

然后开始创建实体类实现流程

创建包：entity、mapper、controller。resource下创建mapping文件夹，用于写sql语句，也可以直接写在mapper的java文件中，下面直接贴代码

Application

@MapperScan("com.meng.demo.mapper") //扫描路径下面的接口
@SpringBootApplication
public class DbDemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(DbDemoApplication.class, args);
    }

}

javaBean对象

public class EmployeePO {
    private Integer id;
    private String lastName;
    private String email;
    private Integer gender;
    private Integer d_id;

Mapper

public interface EmployeeMapper {

    public EmployeePO getById(Integer id);   //根据id查询

    public void insert(EmployeePO employeePO); //新增
}

Controller

@RestController
public class DemoController {

    @Autowired
    EmployeeMapper employeeMapper;

    @GetMapping("/emp/{id}")
    public EmployeePO getEmp(@PathVariable("id") Integer id){
        return employeeMapper.getById(id);
    }

    @GetMapping("/emp")
    public EmployeePO inset(EmployeePO employeePO){
        employeeMapper.insert(employeePO);
        return employeePO;
    }

}

　　

Mapper.xml配置文件

<?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">
<mapper namespace="com.meng.demo.mapper.EmployeeMapper">

    <select id="getById" resultType="com.meng.demo.entity.EmployeePO">
		SELECT
			a.*
		FROM employee a
		WHERE a.id = #{id}
	</select>


    <insert id="insert" keyProperty="id" useGeneratedKeys="true">
		insert into employee(lastName,email,gender,d_id)
		values (#{lastName},#{email},#{gender},#{d_id})
	</insert>

</mapper>

mybatis-config.xml配置文件

<?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>
    <settings>
        <setting name="mapUnderscoreToCamelCase" value="true"/> <!-- 驼峰命名 -->
    </settings>
</configuration>

最终的架构

 最后测试启动

在浏览器中输入：http://localhost:8080/emp?lastName=%E6%B5%8B%E8%AF%9505&email=55555@qq.com&gender=10&d_id=1   插入一条数据

 在浏览器中输入：http://localhost:8080/emp/5   查询一条数据