SpringBoot中mybatis的使用说明(一)

orm框架的本质是简化编程中操作数据库的编码,发展到现在基本上就剩两家了,一个是宣称可以不用写一句SQL的hibernate,一个是可以灵活调试动态sql的mybatis,两者各有特点,在企业级系统开发中可以根据需求灵活使用。发现一个有趣的现象:传统企业大都喜欢使用hibernate,互联网行业通常使用mybatis。

hibernate特点就是所有的sql都用Java代码来生成,不用跳出程序去写(看)sql,有着编程的完整性,发展到最顶端就是spring data jpa这种模式了,基本上根据方法名就可以生成对应的sql了。

mybatis初期使用比较麻烦,需要各种配置文件、实体类、dao层映射关联、还有一大推其它配置。当然mybatis也发现了这种弊端,初期开发了generator可以根据表结果自动生产实体类、配置文件和dao层代码,可以减轻一部分开发量;后期也进行了大量的优化可以使用注解了,自动管理dao层和配置文件等,发展到最顶端就是今天要讲的这种模式了,mybatis-spring-boot-starter就是springboot+mybatis可以完全注解不用配置文件,也可以简单配置轻松上手。

mybatis-spring-boot-starter

官方说明:MyBatis Spring-Boot-Starter will help you use MyBatis with Spring Boot
其实就是myBatis看spring boot这么火热也开发出一套解决方案来凑凑热闹,但这一凑确实解决了很多问题,使用起来确实顺畅了许多。mybatis-spring-boot-starter主要有两种解决方案,一种是使用注解解决一切问题,一种是简化后的老传统。

当然任何模式都需要首先引入mybatis-spring-boot-starter的pom文件,现在最新版本是1.1.1

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

 XML版本

1.添加对应的依赖:

<?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
    http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.example</groupId>
    <artifactId>spring-boot-mybatis</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>spring-boot-mybatis</name>
    <description>Demo project for Spring Boot</description>

    <!--
       spring boot 父节点依赖,
       引入这个之后相关的引入就不需要添加version配置,
       spring boot会自动选择最合适的版本进行添加。
     -->
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.3.RELEASE</version>
        <relativePath/>
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

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

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <!--MySQL数据库驱动-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>

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

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional>
        </dependency>
    </dependencies>

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

</project>

2.在application.properties配置文件中配置信息

#需要先引入SpringBoot和mybatis的整合包:mybatis-spring-boot-starter-web
mybatis.config-location=classpath:mybatis/mybatis-config.xml
mybatis.mapper-locations=classpath:mybatis/mapper/*.xml
mybatis.type-aliases-package=com.dbzhang.demo02.entity

#需要先引入mysql的jar包
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/zdb?useSSL=false&useUnicode=true&characterEncoding=utf-8
spring.datasource.username=zdb
spring.datasource.password=zdb
spring.datasource.max-active=20
spring.datasource.max-idle=8
spring.datasource.min-idle=8
spring.datasource.initial-size=10

SpringBoot会自动加载spring.datasource.*这些配置,数据源会自动的注入到sqlSessionFactory中,sqlSessionFactory会自动的加载到mapper中;

3.编写实体类

package com.winner.po;

public class DemoInfo {

    private Integer id;

    private String name;

    private String password;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }
}

4.添加Mapper接口

package com.winner.mapper;

import com.winner.po.DemoInfo;

public interface DemoInfoMapper {

    DemoInfo queryById(Integer id);

}

在启动类中使用@MapperScan注解扫描mapper接口

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
@MapperScan("com.winner.mapper")
public class SpringBootMybatisApplication {

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

5.编写配置文件

DemoMapper.xml

<?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.winner.mapper.DemoInfoMapper">
    <resultMap id="BaseResultMap"
        type="com.winner.po.DemoInfo">
        <id column="id" property="id" jdbcType="INTEGER" />
        <result column="name" property="name" jdbcType="VARCHAR" />
        <result column="password" property="password" jdbcType="VARCHAR" />
    </resultMap>
    <sql id="Base_Column_List">
        id, name, password
    </sql>
    <select id="queryById" resultMap="BaseResultMap"
        parameterType="java.lang.Integer">
        select
        <include refid="Base_Column_List" />
        from demo_info
        where id = #{id}
    </select>
</mapper>

mybatis-config.xml

<?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>
    <!--根据需要加入有关配置-->
</configuration>

6.编写DemoInfoService

@Service
public class DemoInfoService {

    @Resource
    private DemoInfoMapper demoInfoMapper;

    DemoInfo queryById(Integer id){
        DemoInfo demoInfo = demoInfoMapper.queryById(id);
        return demoInfo;
    }
}

7.编写DemoInfoController

@RestController
public class DemoInfoController {

    @Resource
    private DemoInfoService demoInfoService;

    @RequestMapping("/{id}")
    DemoInfo queryById(@PathVariable Integer id){
        DemoInfo demoInfo = demoInfoService.queryById(id);
        return demoInfo;
    }
}

参考文章:https://www.cnblogs.com/winner-0715/p/6687246.html

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转载自blog.csdn.net/zdb292034/article/details/82178202