spring-boot和mybatis的整合

r囧r小猫 2022-01-23 23:41 202阅读 0赞

在idea里创建一个spring-boot工程 选依赖的时候把web里的web勾上，sql里的mysql和mybatis也勾上 ，这样就会自动帮我们生成依赖 在其中我们需要给mysql的依赖加上版本，不然它会自动去用最新版的（目前mysql最新版已经到了八以上了），我们现在用五点几的就好，有错误也能在网上找到解决方法，采用最新版的如果出现错误，那么解决起来也麻烦

然后在加上druid依赖， 如果是要用到多数据源，就得用 druid-spring-boot-starter

然后在build里设置下配置文件的扫描路径，pom.xml具体依赖如下

<parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>2.1.5.RELEASE</version>
            <relativePath/> 
        </parent>
        <groupId>com.liy</groupId>
        <artifactId>mybatisProject</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <name>mybatisProject</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-web</artifactId>
            </dependency>
            <dependency>
                <groupId>org.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</artifactId>
                <version>2.0.1</version>
            </dependency>
    
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <scope>runtime</scope>
                <version>5.1.30</version>
            </dependency>
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>druid-spring-boot-starter</artifactId>
                <version>1.1.10</version>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <scope>test</scope>
            </dependency>
        </dependencies>
    
        <build>
           <resources>
               <resource>
                   <directory>src/main/java</directory>
                   <includes>
                       <include>**/*.xml</include>
                   </includes>
               </resource>
               <resource>
                   <directory>src/main/resources</directory>
               </resource>
           </resources>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                </plugin>
            </plugins>
        </build>`

然后在application.properties配置文件中配置数据源信息（我这里打算用两个数据源）

spring.datasource.one.username=root
    spring.datasource.one.password=root
    spring.datasource.one.url=jdbc:mysql:///again
    spring.datasource.one.type=com.alibaba.druid.pool.DruidDataSource
    spring.datasource.one.driver-class-name=com.mysql.jdbc.Driver
    
    
    spring.datasource.two.username=root
    spring.datasource.two.password=root
    spring.datasource.two.url=jdbc:mysql:///demo
    spring.datasource.two.type=com.alibaba.druid.pool.DruidDataSource
    spring.datasource.two.driver-class-name=com.mysql.jdbc.Driver

如果只是一个数据源 前缀是spring.datasource.username 这也是默认的扫描前缀

因为我们这里采用两个数据源，所以为了区别两个数据源我们分别给他们加上了

spring.datasource.**one.**username=root
    
    spring.datasource.**two.**username=root

但是我们把前缀改了，那么spring-boot也就找不到默认的前缀，那么这两个数据源的配置信息也就不会去扫描

所以我们得自己去写个配置类，来获取和区别这两个数据源 DatasourceConfig.java

@Configuration
    public class DataSourceConfig {
    
        @Bean
        @ConfigurationProperties("spring.datasource.one")
        DataSource dsOne(){
            return DruidDataSourceBuilder.create().build();
        }
    
        @Bean
        @ConfigurationProperties("spring.datasource.two")
        DataSource dsTwo(){
            return DruidDataSourceBuilder.create().build();
        }
    }

然后得把数据源分别弄给我们的mybatis配置类去 写两个mybatis配置类，内容基本一样，但是用于区分两个数据源 MybatisConfig1

@Configuration
    @MapperScan(basePackages = "com.liy.mapper",sqlSessionFactoryRef = "sqlSessionFactoryBean1",
    sqlSessionTemplateRef = "sqlSessionTemplate1")
    public class MyBatisConfig1 {
    
        @Resource(name = "dsOne")
        DataSource dsOne;
    
        @Bean
        SqlSessionFactory sqlSessionFactoryBean1(){
            SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();
            factoryBean.setDataSource(dsOne);
            SqlSessionFactory factory = null;
            try {
                factory = factoryBean.getObject();
            } catch (Exception e) {
                e.printStackTrace();
            }
            return factory;
        }
    
        @Bean
        SqlSessionTemplate sqlSessionTemplate1(){
            return new SqlSessionTemplate(sqlSessionFactoryBean1());
        }
    
    }

MybatisConfig1

@Configuration
    @MapperScan(basePackages = "com.liy.mapper2",sqlSessionFactoryRef = "sqlSessionFactoryBean2",
    sqlSessionTemplateRef = "sqlSessionTemplate2")
    public class MyBatisConfig2 {
    
        @Resource(name = "dsTwo")
        DataSource dsTwo;
    
        @Bean
        SqlSessionFactory sqlSessionFactoryBean2(){
            SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();
            factoryBean.setDataSource(dsTwo);
            SqlSessionFactory factory = null;
            try {
                factory = factoryBean.getObject();
            } catch (Exception e) {
                e.printStackTrace();
            }
            return factory;
        }
    
        @Bean
        SqlSessionTemplate sqlSessionTemplate2(){
            return new SqlSessionTemplate(sqlSessionFactoryBean2());
        }
    
    }

然后分别写两个mapper包里对应的接口和映射文件  
![在这里插入图片描述][20190531194334190.png]

我们就只测试一下，那就分别查询下

UserMapper 普通的sql语句也可以直接用注解来，不过不推荐

public interface UserMapper {
        //@Select("select * from user")
        public List<User> selectAll();
    }

UserMapper.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.liy.mapper.UserMapper">
        <select id="selectAll" resultType="com.liy.bean.User">
            select * from user
        </select>
    </mapper>

另一个mapper2的代码也就不发了，也是基本和mapper里的一样

只是些路径和数据库查询的表名不太一样

记得写个bean类接收 ， 我找了两个相似的表来查询，所有就只用写一个bean类来接收就行

setter和getter方法就省略了

public class User {
        private int id;
        private String name;
        private int age;
        private String address;

基本都准备好了，那么就开始测试吧

直接在spring-boot工程自带的测试类里测试即可

@RunWith(SpringRunner.class)
    @SpringBootTest
    public class MybatisApplicationTests {
        @Autowired
        UserMapper um;
    
        @Autowired
        UserMapper2 um2;
        @Test
        public void contextLoads() {
            List<User> user = um.selectAll();
            System.out.println(user);
    
            List<User> users = um2.selectAll();
            System.out.println(users);
        }
    
    }

um 和 um2上应该都有红色波浪线，只是springboot未找到还是啥的，但是还是注入进来了

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3Nzc3l5eXk3_size_16_color_FFFFFF_t_70]

两个表的数据也都查询出来了

[20190531194334190.png]: /images/20220124/a68e3ad71a304771a7dc5ba374e3e634.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3Nzc3l5eXk3_size_16_color_FFFFFF_t_70]: /images/20220124/52ad7b40930b4e52b10e7d13b4fc611d.png