SpringBoot09：整合MyBatis.md

整合MyBatis

官方文档：http://mybatis.org/spring-boot-starter/mybatis-spring-boot-autoconfigure/

Maven仓库地址：https://mvnrepository.com/artifact/org.mybatis.spring.boot/mybatis-spring-boot-starter/2.1.3

整合测试

1. 导入 MyBatis 所需要的依赖

   <dependency>
       <groupId>org.mybatis.spring.boot</groupId>
       <artifactId>mybatis-spring-boot-starter</artifactId>
       <version>2.1.3</version>
   </dependency>

2. 配置数据库连接信息（不变）

   spring:
     datasource:
       username: root
       password: admin
       #?serverTimezone=UTC解决时区的报错
       url: jdbc:mysql://localhost:3306/mybatis?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8
       driver-class-name: com.mysql.cj.jdbc.Driver
       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
   
       #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
       filters: stat,wall,log4j
       maxPoolPreparedStatementPerConnectionSize: 20
       useGlobalDataSourceStat: true
       connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=500

3. 测试数据库是否连接成功！

4. 创建实体类，导入 Lombok！

   User.java

   package nuc.ss.pojo;
   
   import lombok.AllArgsConstructor;
   import lombok.Data;
   import lombok.NoArgsConstructor;
   
   @Data
   @AllArgsConstructor
   @NoArgsConstructor
   public class User {
       private int id;
       private String name;
       private String pwd;
   }

5. 创建mapper目录以及对应的 Mapper 接口

   UserMapper.java

   package nuc.ss.mapper;
   
   import nuc.ss.pojo.User;
   import org.apache.ibatis.annotations.Mapper;
   import org.springframework.stereotype.Repository;
   
   import java.util.List;
   
   // 这个注解表示了这是一个 mybatis 的 mapper 类
   @Mapper
   @Repository
   public interface UserMapper {
   
       List<User> queryUserList();
   
       User queryUserById(int id);
   
       int addUser(User user);
   
       int updateUser(User user);
   
       int deleteUser(int id);
   }

6. 对应的Mapper映射文件

   UserMapper.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">
   <!--namespace=绑定一个对应的Dao/Mapper接口-->
   <mapper namespace="nuc.ss.mapper.UserMapper">
       
       <select id="queryUserList" resultType="User">
           select * from mybatis.user;
       </select>
   
       <select id="queryUserById" resultType="User">
           select * from mybatis.user where id = #{id};
       </select>
   
       <insert id="addUser" parameterType="User">
           insert into mybatis.user (id, name, pwd) values (#{id},#{name},#{pwd});
       </insert>
   
       <update id="updateUser" parameterType="User">
           update mybatis.user set name=#{name},pwd = #{pwd} where id = #{id};
       </update>
   
       <delete id="deleteUser" parameterType="int">
           delete from mybatis.user where id = #{id}
       </delete>
   </mapper>

7. maven配置资源过滤问题

   <resources>
       <resource>
           <directory>src/main/java</directory>
           <includes>
               <include>**/*.xml</include>
           </includes>
           <filtering>true</filtering>
       </resource>
   </resources>

8. 编写部门的 UserController 进行测试！

   @RestController
   public class UserController {
       @Autowired
       private UserMapper userMapper;
   
       @GetMapping("/queryUserList")
       public List<User> queryUserList() {
           List<User> userList = userMapper.queryUserList();
   
           for (User user : userList) {
               System.out.println(user);
           }
   
           return userList;
       }
       
        //添加一个用户
       @GetMapping("/addUser")
       public String addUser() {
           userMapper.addUser(new User(7,"阿毛","123456"));
           return "ok";
       }
   
       //修改一个用户
       @GetMapping("/updateUser")
       public String updateUser() {
           userMapper.updateUser(new User(7,"阿毛","123456"));
           return "ok";
       }
   
       @GetMapping("/deleteUser")
       public String deleteUser() {
           userMapper.deleteUser(7);
   
           return "ok";
       }
   }

启动项目访问进行测试！