思路

1. 引入 mybatis-spring-boot-starter、mysql、druid 相关依赖。
2. 在入口类上加上 @mapperScan 注解，作用是扫描 DAO 接口（即数据访问接口）所在包。
3. 建表
4. 开发实体对象
5. 开发 DAO 接口和 mapper 配置文件开发
6. 开发 Service 和 ServiceImpl
7. 开发 Controller
8. 开发页面测试

步骤

1. 新建 web-app 项目，导入相关依赖

   • 完整 XML 文件

2. 修改配置文件

   server.port=8989
   server.servlet.context-path=/springboot_day6
   
   spring.thymeleaf.prefix=classpath:/templates
   spring.thymeleaf.suffix=.html
   spring.thymeleaf.encoding=UTF-8
   spring.thymeleaf.cache=false
   spring.thymeleaf.servlet.content-type=text/html
   spring.resources.static-locations=classpath:/templates/,classpath:/static/
   
   spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
   spring.datasource.driver-class-name=com.mysql.jdbc.Driver
   spring.datasource.url=jdbc:mysql://localhost:3306/test
   spring.datasource.username=root
   spring.datasource.password=1234
   
   mybatis.mapper-locations=classpath:/com/rennen/mapper/*.xml
   # Mapper 映射文件的存放地址
   mybatis.type-aliases-package=com.rennen.entity
   # 别名
   

3. 入口类加上注解，用来做 Mapper 扫描

   @SpringBootApplication
   @MapperScan("com.rennen.dao")
   public class Application {
       public static void main(String[] args) {
           SpringApplication.run(Application.class, args);
       }
   
   }
   

4. 建表和构建实体类

   package com.rennen.entity;
   
   import lombok.AllArgsConstructor;
   import lombok.Data;
   import lombok.NoArgsConstructor;
   import lombok.ToString;
   
   import java.util.Date;
   
   @Data
   @AllArgsConstructor
   @NoArgsConstructor
   @ToString
   public class User {
       private String id;
       private String name;
       private Integer age;
       private Date bir;
   }
   

5. 开发 DAO 接口

   package com.rennen.dao;
   
   import com.rennen.entity.User;
   
   import java.util.List;
   
   public interface UserDAO {
       void save(User user);
       List<User> findAll();
   }
   

6. 编写 Mapper 文件（IDEA 中添加模板）

   <?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.baizhi.dao.ClazzDAO">
       <select id="findAll" resultType="Clazz">
           select * from t_clazz 
       </select>
   </mapper>
   

7. 开发 Service

   //接口
   public interface ClazzService {
       List<Clazz> findAll();
   }
   //实现
   @Service
   @Transactional
   public class ClazzServiceImpl implements  ClazzService {
       @Autowired
       private ClazzDAO clazzDAO;
       
       @Transactional(propagation = Propagation.SUPPORTS)
       @Override
       public List<Clazz> findAll() {
           return clazzDAO.findAll();
       }
   }