SpringBoot专题学习Part21：SpringBoot整合MyBatis的配置及使用 - 配置文件实现

阳光穿透心脏的1/2处 2023-07-18 09:27 7阅读 0赞

**首先** 引入依赖：

<dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>druid</artifactId>
        <version>1.1.10</version>
    </dependency>
    
    
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>log4j-over-slf4j</artifactId>
        <version>1.7.25</version>
    </dependency>
    
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-jdbc</artifactId>
    </dependency>
    <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>2.1.2</version>
    </dependency>
    
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <scope>runtime</scope>
    </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>

然后 配置好数据源  
我选用的是Druid数据源

yml配置文件：

spring:
      datasource:
        driver-class-name: com.mysql.cj.jdbc.Driver
        url: jdbc:mysql://127.0.0.1:3306/springboot_mybatis?useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC
        username: root
        password: 123456
        initialization-mode: always
        type: com.alibaba.druid.pool.DruidDataSource
        #   数据源其他配置
        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
        #   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

然后创建配置类 对Druid进行配置：

@Configuration
    public class DruidConfig {
        
    
        @ConfigurationProperties(prefix = "spring.datasource")
        @Bean
        public DataSource druid()
        {
        
            return new DruidDataSource();
        }
    
        @Bean
        public ServletRegistrationBean statViewServlet()
        {
        
            ServletRegistrationBean<StatViewServlet> srb = new ServletRegistrationBean<>(new StatViewServlet(), "/druid/*");
            // 设置初始化参数
            Map<String,String> initParams=new HashMap<>();
            // 登录后台的用户名
            initParams.put("loginUsername","admin");
            // 登录后台的密码
            initParams.put("loginPassword","123456");
            // 允许访问的ip 默认或为空代表允许所有
            initParams.put("allow","");
            // 不允许访问的ip
            initParams.put("deny","111.111.111.111");
            srb.setInitParameters(initParams);
            return srb;
        }
    
        @Bean
        public FilterRegistrationBean webStatFilter()
        {
        
            FilterRegistrationBean<Filter> frb = new FilterRegistrationBean<>();
            // 传入Druid的监控Filter
            frb.setFilter(new WebStatFilter());
            // 设置初始化参数
            Map<String,String> initParams=new HashMap<>();
            // 设置哪些路径不进行拦截
            initParams.put("exclusions","*.js,*.css,/druid/*");
            frb.setInitParameters(initParams);
            // 设置拦截的请求
            frb.setUrlPatterns(Arrays.asList("/*"));
            return frb;
        }
    }

创建数据表和对应的bean类  
然后就可以开始配置了：

首先 写一个接口：  
接口里面定义了要对数据库进行操作的curd方法  
若没添加@MapperScan注解 则该接口类须加上@Mapper

public interface EmployeeMapper {
        
    
        public Employee getEmployeeById(Integer id);
    
        public void insertEmployee(Employee employee);
    }

之后 配置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>
    
    </configuration>

里面是空的 因为全局配置文件通常是用于配置数据源的  
而数据源在上面已经配好了Druid的了

之后还需要配置**SQL映射的配置文件**：  
映射配置文件放在resources资源目录下  
名字通常取成xxxMapper.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="net.zjitc.springboot.mapper.EmployeeMapper">
        <select id="getEmployeeById" resultType="net.zjitc.springboot.bean.Employee">
            select * from employee where id=#{id}
        </select>
    
        <insert id="insertEmployee">
            insert into employee(lastName,email,gender,d_id) values(#{lastName},#{email},#{gender},#{dId})
        </insert>
    </mapper>

还需要在yml配置文件中进行配置(properties配置文件也行 只不过语法不太一样  
配置的目的是为了让MyBatis知道这些配置文件的存在：

mybatis:
      # MyBatis全局配置文件的路径
      config-location: classpath:mybatis/mybatis-config.xml
      # MyBatis映射配置文件的路径
      mapper-locations: classpath:mybatis/mapper/*.xml

这样就配置完了

简单测试：

@RestController
    public class EmployeeController {
        
    
        @Autowired
        EmployeeMapper employeeMapper;
    
        @GetMapping("/emp/{id}")
        public Employee getEmployee(@PathVariable("id") Integer id)
        {
        
            return employeeMapper.getEmployeeById(id);
        }
    }

![在这里插入图片描述][202003251544235.png]  
测试成功

--------------------

当数据库的字段和bean的属性不一致时 获取的值是null  
此时 可以配置**驼峰映射**

在MyBatis的全局配置文件中进行配置：

注解版的MyBatis和配置文件版的MyBatis可以共存 混合使用

--------------------

[202003251544235.png]: /images/20230528/ddf783d0f06b43c78ad4e6ef2a100d5a.png