Spring Boot + MyBatis

发布于：2024-03-29 ⋅ 阅读:(20) ⋅ 点赞:(0)

一、配置依赖

<!-- MyBatis -->
<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>3.5.3</version>
</dependency>
<!-- junit测试依赖 -->
<dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <scope>test</scope>
</dependency>
<!-- lombok依赖 为了简化实体类的编写代码量 -->
<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
</dependency>

不知道为什么，maven配置的远程仓库(阿里云)一直找不到org.mybatis.spring.boot: mybatis-spring-boot-starter，报如下错误：

Cannot resolve org.mybatis.spring.boot:mybatis-spring-boot-starter:unknown

最终的解决方案是使用MyBatis-plus来替代MyBatis，所以最终使用的是如下依赖信息：

<!-- MyBatis Plus-->
<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-boot-starter</artifactId>
    <version>3.4.1</version>
</dependency>
<!-- junit测试依赖 -->
<dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <scope>test</scope>
</dependency>
<!-- lombok依赖 为了简化实体类的编写代码量 -->
<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
</dependency>

二、配置文件信息

        如果是SpringBoot，在resources目录下创建application.yml文件，这个文件中存放mybaits的相关配置信息。

# 配置数据库的连接字符串
spring:
  datasource:
    url: jdbc:mysql://127.0.0.1:3306/你的数据库?characterEncoding=utf8
    username: 你的数据库用户名
    password: 你的数据库密码
    driver-class-name: com.mysql.cj.jdbc.Driver
    
# 设置 Mybatis 的 xml 保存路径
mybatis:
  mapper-locations: classpath:mapper/*Mapper.xml #实现mapper.java接口和mapper.xml的绑定
  type-aliases-package: com.xj.dao.model #解释参考里有说明
  configuration: # 配置打印 MyBatis 执行的 SQL
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl #需要lombok框架支持，可以添加
    
# 配置打印 MyBatis 执行的 SQL
logging:
  level:
    com:
      example:
        demo: debug

三、项目举例

1.创建一个Spring Boot项目

参考：Spring Boot之创建一个Spring Boot项目（一）_<plugin> <groupid>org.springframework.boot</groupi-CSDN博客

2.项目架构

3.代码实现

pom.xml:

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.xj</groupId>
  <artifactId>SpringBootStudyProject</artifactId>
  <version>1.0-SNAPSHOT</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.4.5</version>
        <relativePath/>
    </parent>

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

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

        <!--导入JDBC的场景启动器-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jdbc</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-configuration-processor</artifactId>
            <optional>true</optional>
        </dependency>

        <!--jquery引入-->
        <dependency>
            <groupId>org.webjars</groupId>
            <artifactId>jquery</artifactId>
            <version>3.6.0</version>
        </dependency>

        <!--Thymeleaf 启动器-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-thymeleaf</artifactId>
        </dependency>

        <!--导入数据库驱动-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>

        <!-- MyBatis Plus-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.4.1</version>
        </dependency>
        <!-- junit测试依赖 -->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <scope>test</scope>
        </dependency>
        <!-- lombok依赖 为了简化实体类的编写代码量 -->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
    </dependencies>

    <!--build标签描述了如何来编译及打包项目，而具体的编译和打包工作是通过build中配置的 plugin 来完成-->
    <build>
        <plugins>
            <!--使用SpringBoot的打包插件-->
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <executions>
                    <execution>
                        <goals>
                            <goal>repackage</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

application.yml:

#默认配置
server:
    port: 8080

spring:
    datasource: #数据源连接信息
        username: root
        password: 12345
        url: jdbc:mysql://127.0.0.1:3306/demo?useUnicode=true&characterEncoding=UTF-8
        driver-class-name: com.mysql.cj.jdbc.Driver
    profiles:
        active: dev #切换配置,指定使用哪个profile

# 设置 Mybatis 的 xml 保存路径
mybatis-plus:
    mapper-locations: classpath:mapper/*Mapper.xml
    type-aliases-package: com.xj.dao.model
    configuration: # 配置打印 MyBatis 执行的 SQL
        log-impl: org.apache.ibatis.logging.stdout.StdOutImpl #需要lombok框架支持，可以添加

# 配置打印 MyBatis 执行的 SQL
logging:
    level:
        com:
            example:
                demo: debug


---
#开发环境
server:
    port: 8081

spring:
    config:
        activate:
            on-profile: dev
---
#测试环境
server:
    port: 8082

spring:
    config:
        activate:
            on-profile: test
---
#生产环境
server:
    port: 8083

spring:
    config:
        activate:
            on-profile: prod

logging:
    config: classpath:logback-spring.xml #指定使用哪个日志配置文件

Student.java:

package com.xj.dao.model;

import com.baomidou.mybatisplus.annotation.TableId;
import lombok.Data;
import org.springframework.data.relational.core.mapping.Column;
import java.io.Serializable;

/**
 * @Author: xjfu
 * @Create: 2024/03/25 16:20
 * @Description:
 */
@Data
public class Student implements Serializable {
    private static final long serialVersionUID = 1L;

    @TableId(value = "name")
    private String name;

    @Column(value = "age")
    private Integer age;
}

StudentMapper.java:

package com.xj.dao.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.xj.dao.model.Student;
import org.springframework.stereotype.Repository;
import java.util.List;

/**
 * @Author: xjfu
 * @Create: 2024/03/25 16:26
 * @Description:
 */
@Repository
public interface StudentMapper extends BaseMapper<Student> {

    public List<Student> selectAll();
}

StudentMapper.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="com.xj.dao.mapper.StudentMapper">

    <resultMap id="BaseResultMap" type="com.xj.dao.model.Student">
        <result column="name" property="name" />
        <result column="age" property="age" />
    </resultMap>

    <select id="selectAll" resultType="com.xj.dao.model.Student">
        SELECT *
        FROM student;
    </select>

</mapper>

MainApplication.java:

package com.xj.main;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ComponentScan;

/**
 * @Author : xjfu
 * @Date : 2022/6/8 8:38
 * @Description :Spring Boot 启动类
 */
@ComponentScan("com.xj")
@SpringBootApplication
@MapperScan("com.xj.dao.mapper")
public class MainApplication {
    public static void main(String[] args) {
        try{
            SpringApplication.run(MainApplication.class, args);
        }catch (Exception e){
            e.printStackTrace();
        }
    }
}

MyBatisTest:

package com.xj.main;

import com.xj.dao.mapper.StudentMapper;
import com.xj.dao.model.Student;
import org.junit.jupiter.api.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import java.sql.SQLException;
import java.util.List;

/**
 * @Author : xjfu
 * @Date : 2024/3/35 16:34
 * @Description : MyBatis 测试类
 */
@SpringBootTest(classes = MainApplication.class, webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
public class MyBatisTest {

    private static final Logger log = LoggerFactory.getLogger(MyBatisTest.class);

    @Autowired
    StudentMapper studentMapper;

    @Test
    void testJdbc() throws SQLException{

        List<Student> students = studentMapper.selectAll();

        for (Student s : students){
            System.out.println(s.toString());
        }
    }
}

数据库：

CREATE TABLE `student` (
  `name` varchar(255) DEFAULT NULL,
  `age` int DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci;

4.运行结果

四、参考

1.在 SpringBoot 中 初步使用 MyBatis_springboot mybatis-CSDN博客

2.SpringBoot结合MyBatis 【超详细】_springboot mybatis-CSDN博客

3.Cannot resolve org.mybatis.spring.bootmybatis-spring-boot-_cannot resolve org.mybatis.spring.boot:mybatis-spr-CSDN博客

4.SpringBoot：CONDITIONS EVALUATION REPORT-CSDN博客 

5.@MapperScan注解使用-CSDN博客

6.mybatis的mapper-locations配置_mapperlocations属性怎么配置-CSDN博客

7.type-aliases-package的用法-CSDN博客

8.什么是MyBatis-CSDN博客

9.mybatis – MyBatis 3 | XML 映射器

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