【spring boot2】第9篇：spring boot 整合 mybatis

雨点打透心脏的1/2处 2022-03-07 17:08 231阅读 0赞

# 引入starter #

修改pom.xml文件,整合mybatis需要如下的包

<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>2.0.0</version>
    </dependency>
    
    
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <scope>runtime</scope>
    </dependency>
    
    
    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>druid</artifactId>
        <version>1.1.12</version>
    </dependency>
    
    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>druid-spring-boot-starter</artifactId>
        <version>1.1.10</version>
    </dependency>

# durid连接池配置 #

## 修改yml文件 ##

spring:
      datasource:
        username: root
        password: root
        url: jdbc:mysql://127.0.0.1:3306/sff_test
        driver-class-name: com.mysql.jdbc.Driver
        # 指定自己使用的数据源
        type: com.alibaba.druid.pool.DruidDataSource
    
        # DruidDataSource 其他属性配置
        druid:
         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
         maxPoolPreparedStatementPerConnectionSize: 20
         useGlobalDataSourceStat: true
         filter:
          stat:
           enabled: true
           log-slow-sql: true
          wall:
           enabled: true

## 注入duird配置 ##

@Configurable
    public class DruidConfig {
        @Bean
        @ConfigurationProperties("spring.datasource.druid")
        public DataSource dataSourceTwo() {
            return DruidDataSourceBuilder.create().build();
        }
        /**
         * 配置一个管理后台的Servlet
         *
         * @return
         */
        @Bean
        public ServletRegistrationBean statViewServlet() {
            ServletRegistrationBean bean = new ServletRegistrationBean(new StatViewServlet(), "/druid/*");
            Map<String, String> initParams = new HashMap<>();
    
            initParams.put("loginUsername", "admin");
            initParams.put("loginPassword", "admin");
            initParams.put("allow", "");//默认就是允许所有访问
    
            bean.setInitParameters(initParams);
            return bean;
        }
        /**
         * 配置一个web监控的filter
         *
         * @return
         */
        @Bean
        public FilterRegistrationBean webStatFilter() {
            FilterRegistrationBean bean = new FilterRegistrationBean();
            bean.setFilter(new WebStatFilter());
    
            Map<String, String> initParams = new HashMap<>();
            //通过 localhost:8080/druid/ 可以访问到监控后台
            initParams.put("exclusions", "*.js,*.css,/druid/*");
    
            bean.setInitParameters(initParams);
            bean.setUrlPatterns(Arrays.asList("/*"));
    
            return bean;
        }
    }

# 配置mybatis组件 #

## 使用mybatis注解 ##

### 定义mapper接口 ###

@Mapper
    public interface DeptMapper {
    
        @Select("select * from dept")
        List<Dept> selectAll();
    }

### 注入mybatis相关配置 ###

public class MybatisConfig {
    
        //定制mybatis配置
        @Bean
        public ConfigurationCustomizer configurationCustomizer() {
            return new ConfigurationCustomizer() {
                @Override
                public void customize(Configuration configuration) {
                    //开启驼峰命令
                    configuration.setMapUnderscoreToCamelCase(true);
                }
            };
        }
    }

1.  开启驼峰命名，如果不开启会导致数据库中的这种`dept_name`等字段无法转换为bean中的`deptName`字段
2.  在我们的`mapper`接口很多的时候，比如说有多个类似 `DeptMapper`时，如果每个`mapper`都写`@Mapper`注解很麻烦，此时可以在`MybatisConfig`配置类上使用`@MapperScan(value = "com.sff.spring.boot.mybatis.dao")`这个注解，去掉`@Mapper`注解即可

## 使用mapper.xml文件 ##

### 定义mapper接口 ###

public interface EmpMapper {
        List<Emp> selectAll();
    }

### 定义mapper.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">
    <mapper namespace="com.sff.spring.boot.mybatis.dao.EmpMapper">
        <select id="selectAll" resultType="Emp">
            select * from emp
        </select>
    </mapper>

**注意：使用mapper的xml文件时，记得将mapper接口注入的容器中，使用`@Mapper`\`或者`@MapperScan`注解**

### 定义mybatis的全局配置文件 ###

<?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"/>
        </settings>
    
        <typeAliases>
            
            <package name="com.sff.spring.boot.mybatis.domain"/>
        </typeAliases>
    </configuration>

### 修改yml文件，指定mybatis配置、mapper文件路径 ###

mybatis:
      mapper-locations: classpath:mybatis/mapper/*.xml
      config-location: classpath:mybatis/mybatis-config.xml

# 自定义starter #

*  [文章][Link 1]
 *  [文章][Link 2]

# 其他参考 #

*  [mybatis文档][mybatis]
 *  [案例源码][Link 3]

[Link 1]: http://www.importnew.com/30610.html
[Link 2]: http://www.importnew.com/24164.html
[mybatis]: http://www.mybatis.org/mybatis-3/getting-started.html
[Link 3]: https://github.com/shifefiei/spring-boot/tree/master/spring-boot-mybatis