[Java知识库]SpringBoot：整合MyBatis

SpringBoot：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/2.1.1

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>2.1.1</version>
</dependency>

2、配置数据库连接信息（不变）

spring:
  datasource:
    username: root
    password: 123456
    #?serverTimezone=UTC解决时区的报错
    url: jdbc:mysql://localhost:3306/mytest?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
#整合mybatis
mybatis:
  type-aliases-package: cn.sxt.mybaits.pojo
  mapper-locations: classpath:mybaits/mapper/*.xml

3、测试数据库是否连接成功！

4、创建实体类，导入 Lombok
完整的pom依赖

<dependencies>


        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.1</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/log4j/log4j -->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>

        <!--        druid-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.21</version>
        </dependency>

        <!--        JDBC-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>

        <!--        WEB-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!--        mySQL-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
    </dependencies>

pojo包下的实体类（User ）

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import org.springframework.web.bind.annotation.Mapping;

@Data
@NoArgsConstructor
@AllArgsConstructor
public class User {
    public Integer id;
    public String username;
    public String password;
}

5、创建mapper目录以及对应的 Mapper 接口（UserMapper ）

package cn.sxt.mybaits.mapper;

import cn.sxt.mybaits.pojo.User;
import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Repository;
import org.springframework.web.bind.annotation.Mapping;

import java.util.List;

@Mapper
@Repository
public interface UserMapper {
    //获取所有用户信息
    List<User> queryUserList();
    //通过id查找用户
    User findUserById(int id);
    //添加用户
    int addUser(User user);
    //修改用户
    int updateUser(User user);
    //删除用户
    int deleteUser(int id);
}

6、对应的Mapper映射文件
（在resource文件夹下面建立一个mapper文件夹，创建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="cn.sxt.mybaits.mapper.UserMapper">
    <select id="queryUserList" resultType="User">
        select * from user
    </select>

    <select id="findUserById" resultType="User">
        select * from user where id=#{id}
    </select>

    <insert id="addUser" parameterType="User">
        insert into user (id,username,password) values(#{id},#{username},#{password})
    </insert>

    <update id="updateUser" parameterType="User">
        update user set username=#{username},password=#{password} where id=#{id}
    </update>

    <delete id="deleteUser" >
        delete from user where id=#{id}
    </delete>
</mapper>

7、maven配置资源过滤问题(在yaml文件中写，上面的yaml代码片已经都写好啦)

#整合mybatis
mybatis:
  type-aliases-package: cn.sxt.mybaits.pojo
  mapper-locations: classpath:mybaits/mapper/*.xml

8、编写用户的 UserController 进行测试！

package cn.sxt.mybaits.controller;

import cn.sxt.mybaits.mapper.UserMapper;
import cn.sxt.mybaits.pojo.User;
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 java.util.List;

@RestController
public class UserController {
    @Autowired
    private UserMapper userMapper;
    @GetMapping("/queryUserList")
    public List<User> queryUserList(){
        List<User> users = userMapper.queryUserList();
        return users;
    }

   //添加
    @GetMapping("/addUser")
    public String addUser(){
        userMapper.addUser(new User(9,"sxt","12345"));
        return "addOk";
    }
    //修改
    @GetMapping("/updateUser")
    public String updateUser(){
        userMapper.updateUser(new User(9,"sxt1","123"));
        return "updateOk";
    }
    //删除
    @GetMapping ("/deleteUser")
    public String deleteUser(){
        userMapper.deleteUser(9);
        return "deleteOk";
    }
    //通过id查找
    @GetMapping("/findUserById")
    public User findUserById(){
        User user = userMapper.findUserById(4);
        return user;
    }


}

一整个项目