1. 项目创建

创建一个空maven项目:

2. spring

(1) 导包

 <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <version>5.3.22</version>
    </dependency>

(2) 配置类

@Configuration
public class SpringConfig {

}

3. mybatis

(1) maven导包

    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis</artifactId>
      <version>3.5.13</version>
    </dependency>
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>8.0.23</version>
    </dependency>

(2) mybatis配置文件

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "https://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <properties resource="jdbc.properties"></properties>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="${driver}"/>
                <property name="url" value="${url}"/>
                <property name="username" value="${username}"/>
                <property name="password" value="${password}"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <!--指定mapper映射文件在哪-->
        <mapper resource=""/>
    </mappers>
</configuration>

(3) 连接配置文件

driver = com.mysql.cj.jdbc.Driver
url = jdbc:mysql://localhost:3306/stu
username = root
password = xjy1234

(4) mapper映射文件

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "https://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.xjy.Mapper">
    
</mapper>

(5) 在spring配置类中注册sqlsession的bean

    @Bean
    public SqlSession getSqlSession() throws IOException {
        return new SqlSessionFactoryBuilder()
                .build(Resources.getResourceAsStream("MybatisConfig.xml"))
                .openSession();
    }

springMVC

(1) maven导包

	<!--需要注释掉上面引入的spring-context,不然可能会引起版本冲突(spring-webmvc已经含有spring-context)-->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>6.0.11</version>
    </dependency>
    <dependency>
      <groupId>jakarta.servlet</groupId>
      <artifactId>jakarta.servlet-api</artifactId>
      <version>5.0.0</version>
    </dependency>
        <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-databind</artifactId>
      <version>2.13.3</version>
    </dependency>

(2) springMVC配置类

@Configuration
@EnableWebMvc
public class MvcConfig{
}

(3) 初始化类

public class servletInit extends AbstractAnnotationConfigDispatcherServletInitializer {
    @Override
    protected Class<?>[] getRootConfigClasses() {
        return new Class[]{SpringConfig.class};
    }

    @Override
    protected Class<?>[] getServletConfigClasses() {
        return new Class[]{MvcConfig.class};
    }

    @Override
    protected String[] getServletMappings() {
        return new String[]{"/"};
    }
}

5. 测试

(1) 创建3层架构

分别在spring配置类和mvc配置类中添加包扫描:

@ComponentScan({"com.xjy.service"}) // spring包扫描
@ComponentScan("com.xjy.controller")//mvc包扫描

(2) 编写Controller层

@RestController
@RequestMapping("/user")
public class userController {

    @Autowired
    private UserService userService;
    @GetMapping("/{id}")
    @ResponseBody
    public String getUserName(@PathVariable int id) throws IOException {
        System.out.println("接受到请求");
        String name = userService.getUserName(id);
        System.out.println("controller接受到返回结果"+name);
        return name;
    }
}

service层

接口:

package com.xjy.service;

public interface UserService {
    String getUserName(int id);
}

实现类:

@Service
public class UserServiceImpl implements UserService {
    @Autowired
    private SqlSession session;
    @Override
    public String getUserName(int id) throws IOException {
        UserMapper mapper = session.getMapper(UserMapper.class);
        String name = mapper.getUserName(id);
        return name;
    }
}

mapper(dao)层

接口:

public interface UserMapper {
    String getUserName(int id);
}

sql映射文件:

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "https://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.xjy.mapper.UserMapper">
    <select id="getUserName" resultType="java.lang.String">
        select name from user where id = #{id}
    </select>
</mapper>

tomcat部署启动

打包方式修改为war:

访问路劲修改为/:

启动tomcat服务,用postman进行访问:

成功接收: