springboot整合mybatis

 导入依赖：

<dependencies>
        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-webartifactId>
        dependency>

        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-testartifactId>
            <scope>testscope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintagegroupId>
                    <artifactId>junit-vintage-engineartifactId>
                exclusion>
            exclusions>
        dependency>

        
        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-jdbcartifactId>
        dependency>

        <dependency>
            <groupId>mysqlgroupId>
            <artifactId>mysql-connector-javaartifactId>
        dependency>

        <dependency>
            <groupId>org.mybatisgroupId>
            <artifactId>mybatisartifactId>
            <version>3.4.6version>
        dependency>

        <dependency>
            <groupId>com.alibabagroupId>
            <artifactId>druidartifactId>
            <version>1.2.1version>
        dependency>

        <dependency>
            <groupId>log4jgroupId>
            <artifactId>log4jartifactId>
            <version>1.2.12version>
        dependency>


        
        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-thymeleafartifactId>
        dependency>
    dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.bootgroupId>
                <artifactId>spring-boot-maven-pluginartifactId>
            plugin>
        plugins>

        <resources>
            <resource>
                <directory>src/main/javadirectory>
                <includes>
                    <include>**/*.propertiesinclude>
                    <include>**/*.xmlinclude>
                includes>
                <filtering>falsefiltering>
            resource>
            <resource>
                <directory>src/main/resourcesdirectory>
                <includes>
                    <include>**/*.propertiesinclude>
                    <include>**/*.xmlinclude>
                includes>
                <filtering>falsefiltering>
            resource>
        resources>
    build>

新建个application.yaml写数据库的配置

spring:
  datasource:
    username: root
    password: 111111
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://localhost:3306/smbms?serverTimezone=GMT%2B8&useSSL=true
    type: com.alibaba.druid.pool.DruidDataSource

    #----------------------------------------------------------------------------------------
    #Spring Boot 默认是不注入这些属性值的，需要自己绑定
    #druid 数据源专有配置
    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


    #druid 牛逼就牛逼在自带监控功能，还可以 ↓
    #配置监控统计拦截的filters，stat:监控统计、log4j：日志记录、wall：防御sql注入
    #如果允许时报错  java.lang.ClassNotFoundException: org.apache.log4j.Priority
    #则导入 log4j 依赖即可，Maven 地址：https://mvnrepository.com/artifact/log4j/log4j
    #看filtes：这块有log4j 所以不写log4j的依赖就会报错
    filters: stat,wall,log4j
    maxPoolPreparedStatementPerConnectionSize: 20
    useGlobalDataSourceStat: true
    connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=500
    #----------------------------------------------------------------------------------------

写一下UserMapper.interface

/*
* 从mybatis3.4.0开始加入了@Mapper注解，目的就是为了不再写mapper映射文件（那个xml写的是真的蛋疼。。。）。
* @Mapper 是mybatis的注解  @Repository让Spring容器帮我们自动装配bean
* */
@Mapper
@Repository
public interface UserMapper {
    //查询
    public List queryAll();
    //添加数据
    public int addUser(User user);
    //根据用户名模糊查询
    public List queryByLikeName(String username);
}

写一下UserMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="com.example.demo.mapper.UserMapper">

    <select id="queryAll" resultType="com.example.demo.pojo.User">
        select * from user
    select>

    <insert id="addUser" parameterType="com.example.demo.pojo.User">
        insert into user (username,userid)
        values (#{username},${userid});
    insert>

    <select id="queryByLikeName" parameterType="String" resultType="com.example.demo.pojo.User">
        select * from user where username like #{arg0}
    select>

mapper>

在主启动类头上写mapper扫描注解

//去扫描mapper
@MapperScan("com.example.demo.mapper")
@SpringBootApplication
public class DemoApplication {

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

 测试一下

@SpringBootTest
class DemoApplicationTests {

    @Autowired
    DataSource dataSource;

    @Autowired
    UserMapper userMapper;

    @Test
    void contextLoads() {
        System.out.println(dataSource.getClass()); //查看现在所使用的数据源
        final List users = userMapper.queryAll();
        for (User user : users) {
            System.out.println(user);
        }
    }

    @Test
    void contextLoads2() {
        final List users = userMapper.queryByLikeName("%用%");
        for (User user : users) {
            System.out.println(user);
        }
    }

}