spring-boot+mybatis开发实战：如何在spring-boot中使用myabtis持久层框架

前言：

本项目基于maven构建，使用mybatis-spring-boot作为spring-boot项目的持久层框架

spring-boot中使用mybatis持久层框架与原spring项目使用方式和注解都不相同，需要依赖mybatis-spring-boot包

1、引入mybatis和数据库及其他项目依赖

1.1、引入mybatis依赖

<!-- mybatis-spring-boot -->
		<dependency>
			<groupId>org.mybatis.spring.boot</groupId>
			<artifactId>mybatis-spring-boot-starter</artifactId>
			<version>1.1.1</version>
		</dependency>

1.2、引入mysql 驱动

<!-- mysql-->
		<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
		</dependency>

1.3、项目pom.xml一览

<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 http://maven.apache.org/maven-v4_0_0.xsd">

	<modelVersion>4.0.0</modelVersion>

	<groupId>cn.eguid.carDeviceInfoSys</groupId>
	<artifactId>carSys-web</artifactId>
	<packaging>war</packaging>
	<version>1.4.0-SNAPSHOT</version>
	<name>carSys-web</name>

	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>1.4.0.RELEASE</version>
	</parent>

	<dependencies>
		<!-- spring-boot web -->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
			<!--<exclusions> <exclusion> <groupId>org.springframework.boot</groupId> 
				<artifactId>spring-boot-starter-tomcat</artifactId> </exclusion> </exclusions> -->
		</dependency>
		<!-- spring aop -->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-aop</artifactId>
		</dependency>
		<!-- mysql-->
		<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-jdbc</artifactId>
		</dependency>
		<!-- https://mvnrepository.com/artifact/redis.clients/jedis -->
		<dependency>
			<groupId>redis.clients</groupId>
			<artifactId>jedis</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
		<dependency>
			<groupId>com.jayway.jsonpath</groupId>
			<artifactId>json-path</artifactId>
			<scope>test</scope>
		</dependency>
		<!-- mybatis-spring-boot -->
		<dependency>
			<groupId>org.mybatis.spring.boot</groupId>
			<artifactId>mybatis-spring-boot-starter</artifactId>
			<version>1.1.1</version>
		</dependency>

		<!-- fastjson -->
		<dependency>
			<groupId>com.alibaba</groupId>
			<artifactId>fastjson</artifactId>
			<version>1.2.17</version>
		</dependency>
		
		<dependency>
			<groupId>dom4j</groupId>
			<artifactId>dom4j</artifactId>
			<version>1.6.1</version>
		</dependency>

	</dependencies>

	<profiles>
		<profile>
			<id>production</id>
			<dependencies>
				<!-- This sample is a test for the autoconfig when commons-pool is *absent*. 
					In production it would be useful to enable pooling by using this dependency. -->
				<dependency>
					<groupId>commons-pool</groupId>
					<artifactId>commons-pool</artifactId>
					<type>pom.lastUpdated</type>
				</dependency>
			</dependencies>
		</profile>
	</profiles>

	<!-- Package as an executable jar -->
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>
	<repositories>
		<repository>
			<id>spring-releases</id>
			<url>https://repo.spring.io/libs-release</url>
		</repository>
	</repositories>
	<pluginRepositories>
		<pluginRepository>
			<id>spring-releases</id>
			<url>https://repo.spring.io/libs-release</url>
		</pluginRepository>
	</pluginRepositories>
</project>

2、配置数据库连接参数、设置mybatis的mappers所在包以及spring-boot服务参数配置

在项目根目录下创建一个application.properties，该文件用于定义spring-boot的相关参数及数据库参数，以及配置mybatis的mappers扫描路径

如果是maven项目，application.properties放在src/main/resource/目录下

配置如下：

spring.datasource.url=jdbc:mysql://127.0.0.1:3306/test
spring.datasource.username=root
spring.datasource.password=eguid
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.max-idle=5
spring.datasource.max-wait=10000
spring.datasource.min-idle=1
spring.datasource.initial-size=3

server.port=8088
server.session.timeout=10
server.tomcat.max-threads=800
server.tomcat.uri-encoding=UTF-8

mybatis.mapperLocations=classpath:cn/eguid/carSysWEB/mappers/*.xml

3、mybatis的dao接口及mapper.xml实现

3.1、定义mybatis的dao接口

该接口与mybatis-spring方式不同，需要加上一个@Mapper注解

@Mapper注解用于声明该接口为mybatis的dao接口

package cn.eguid.carSysWeb.dao;

import java.util.List;

import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Param;

import cn.eguid.carSysWeb.entity.DepInfo;
//使用Mapper注解声明该接口为mybatis的dao接口
@Mapper
public interface GetInfoDao {

	public List<DepInfo> getRootInfo();

	public List<DepInfo> getDepInfo(@Param(value = "parentCoding") String org_parent_coding);
	
	public List<DepInfo> getDepInfoById(@Param(value="dep_id") String dep_id);
}

3.2、dao接口对应的mapper.xml

mapper.xml与原mybatis写法相同

<!DOCTYPE mapper
    PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
    "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="cn.eguid.carSysWeb.dao.GetInfoDao">
 <resultMap type="cn.eguid.carSysWeb.entity.DepInfo" id="depMap">
		<id column="org_coding" property="dep_id"/>
		<result column="org_name" property="dep_name"/>
		<result column="org_parent_coding" property="dep_parent_coding"/>
		<result column="last_time" property="last_time"/>
	</resultMap>
<select id="getRootInfo" resultMap="depMap">
select * from car_organization where org_parent_coding is null
</select>
<select id="getDepInfo" parameterType="string" resultMap="depMap">
SELECT * FROM car_organization where org_parent_coding=#{parentCoding,jdbcType=VARCHAR}
</select>
<select id="getDepInfoById" parameterType="string" resultMap="depMap">
SELECT * FROM car_organization where org_coding=#{dep_id}
</select>
</mapper>

补充：

做完以上步骤，就可以在service中直接通过spring的IOC注解注入mybatis的dao实现，我这里的dao接口是GetInfoDao，所以是注入‘getInfoDao’就可以正确引用该持久层；

注意：必须在spring-boot的入口类中开启@ComponentScan注解才能扫描到项目中所有注解

package cn.eguid.carSysWeb;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;

import org.springframework.context.annotation.ComponentScan;

@SpringBootApplication
//开启通用注解扫描
@ComponentScan
public class Application extends org.springframework.boot.web.support.SpringBootServletInitializer {
	/**
	 * 实现SpringBootServletInitializer可以让spring-boot项目在web容器中运行
	 */
	@Override
	protected SpringApplicationBuilder configure(SpringApplicationBuilder builder) {
		builder.sources(this.getClass());
		return super.configure(builder);
	}

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

5、总结：

1、spring-boot项目中使用mabatis需要依赖mybatis-spring-boot

2、需要在application.xml中定义数据库连接参数以及mybatis的mappers文件扫描路径

3、mybatis的dao接口需要加上@Mapper注解才能被spring-boot正确扫描到

4、spring-boot开启注解扫描的注解是@ComponentScan