一.整合Mybatis框架
1.步骤:
-
在整合Druid的基础上继续(略)
-
pom.xml中添加mybatis依赖
-
编写实体类
-
编写mapper层(dao层)
-
编写mapper映射文件
-
在application.yml文件中添加配置
-
编写控制器
2.pom.xml中添加mybatis依赖
<!-- 引入 myBatis,这是 MyBatis官方提供的适配 Spring Boot 的,而不是Spring Boot自己的-->
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>2.1.0</version>
</dependency>
3.编写实体类
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {
private int id;
private String name;
private String pwd;
}
4.编写mapper层(dao层)
-
新建mapper目录,添加UserMapper.java接口
import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Repository;
import ustc.wzh.pojo.User;
import java.util.List;
//@Mapper : 表示本类是一个 MyBatis 的 Mapper,等价于以前 Spring 整合 MyBatis 时的 Mapper 接口
@Mapper
@Repository
public interface UserMapper {
//选择全部用户
List<User> selectUser();
//根据id选择用户
User selectUserById(int id);
//添加一个用户
int addUser(User user);
//修改一个用户
int updateUser(User user);
//根据id删除用户
int deleteUser(int id);
}
5.编写mapper映射文件
-
在resources目录下建立mybatis目录,在mybatis下建立mapper目录,在mapper中建立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">
<mapper namespace="ustc.wzh.mapper.UserMapper">
<select id="selectUser" resultType="User">
select * from user
</select>
<select id="selectUserById" resultType="User">
select * from user where id = #{id}
</select>
<insert id="addUser" parameterType="User">
insert into user (id,name,pwd) values (#{id},#{name},#{pwd})
</insert>
<update id="updateUser" parameterType="User">
update user set name=#{name},pwd=#{pwd} where id = #{id}
</update>
<delete id="deleteUser" parameterType="int">
delete from user where id = #{id}
</delete>
</mapper>
6.在application.yml文件中添加配置
-
在application.yml文件末尾追加mybatis配置的映射以及实体类的路径
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myBatis 与 spring 整合后,配置数据源、事务、连接数据库的账号、密码等就交由 spring 管理。
#指定myBatis的核心配置文件与Mapper映射文件
mybatis:
mapper-locations: classpath:mybatis/mapper/*.xml
# 注意:对应实体类的路径
type-aliases-package: ustc.wzh.pojo
7.编写控制器
import com.alibaba.fastjson.JSON;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import ustc.wzh.mapper.UserMapper;
import ustc.wzh.pojo.User;
import java.util.List;
@RestController
@RequestMapping("/mybatis")
public class UserController {
@Autowired
private UserMapper userMapper;
//选择全部用户
@GetMapping("/selectUser")
public String selectUser(){
List<User> users = userMapper.selectUser();
for (User user : users) {
System.out.println(user);
}
return "mybatis-selectUser:"+JSON.toJSONString(users);
}
//根据id选择用户
@GetMapping("/selectUserById")
public String selectUserById(){
User user = userMapper.selectUserById(1);
System.out.println(user);
return "mybatis-selectUserById:"+JSON.toJSONString(user);
}
//添加一个用户
@GetMapping("/addUser")
public String addUser(){
User user = new User(5,"阿毛","456789");
userMapper.addUser(user);
return "mybatis-addUser:"+JSON.toJSONString(user);
}
//修改一个用户
@GetMapping("/updateUser")
public String updateUser(){
User user = new User(5,"阿毛","421319");
userMapper.updateUser(user);
return "mybatis-updateUser:"+JSON.toJSONString(user);
}
//根据id删除用户
@GetMapping("/deleteUser")
public String deleteUser(){
userMapper.deleteUser(5);
return "mybatis-deleteUser:ok";
}
}
8.项目架构