Spring Boot 整合 MyBatis

LiAng2023年11月17日大约 4 分钟约 870 字

应用实例

修改 application.yml 注释掉

	# 配置druid和监控功能
#    druid:
#      stat-view-servlet:
#        enabled: true
#        login-username: jack
#        login-password: 123
#        reset-enable: false
#      web-stat-filter: #配置web监控
#        enabled: true
#        url-pattern: /*
#        exclusions: '*.js,*.gif,*.jpg,*.png,*.css,*.ico,/druid/*'
#      filter:
#        stat: #sql监控
#          slow-sql-millis: 1000
#          log-slow-sql: true
#          enabled: true
#        wall: #配置sql防火墙
#          enabled: true
#          config:
#            drop-table-allow: false # 不允许删除表
#            select-all-column-allow: false # 不允许查询所有字段的语句

将 DruidDataSourceConfig.java 注释打开

创建数据库和表

CREATE DATABASE `springboot_mybatis` 
use `springboot_mybatis` 
CREATE TABLE `monster` (`id` INT NOT NULL AUTO_INCREMENT, 
                        `age` INT NOT NULL, 
                        `birthday` DATE DEFAULT NULL, 
                        `email` VARCHAR(255) DEFAULT NULL,
                        `gender` char(1) DEFAULT NULL, 
                        `name` VARCHAR(255) DEFAULT NULL, 
                        `salary` DOUBLE NOT NULL, 
                        PRIMARY KEY (`id`) 
                       ) CHARSET=utf8
SELECT * FROM `monster`
insert into monster values(null, 20, '2000-11-11', 'nmw@sohu.com', '男', '牛魔王', 5000.88); 
insert into monster values(null, 10, '2011-11-11', 'bgj@sohu.com', '女', '白骨精', 8000.88);

创建Maven项目

修改 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.lzw</groupId>
    <artifactId>springboot-mybatis</artifactId>
    <version>1.0-SNAPSHOT</version>

    <!--导入springboot父工程-规定写法-->
    <parent>
        <artifactId>spring-boot-starter-parent</artifactId>
        <groupId>org.springframework.boot</groupId>
        <version>2.5.3</version>
    </parent>

    <!--引入相关的依赖-->
    <dependencies>
        <!--引入web starter-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!--引入mybatis starter-->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.2.2</version>
        </dependency>

        <!--引入mysql驱动: 这使用版本仲裁 8.0.26-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>

        <!--引入配置处理器 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-configuration-processor</artifactId>
        </dependency>

        <!--引入lombok-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>

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

        <!--引入druid依赖-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.17</version>
        </dependency>
    </dependencies>

</project>

创建 src/main/resources/application.yml

server:
  port: 9090
spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/springboot_mybatis?useSSL=true&useUnicode=true&characterEncoding=UTF-8
    username: root
    password: 123456

创建 src/main/java/com/lzw/springboot/mybatis/Application.java

package com.lzw.springboot.mybatis;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

/**
 * @author LiAng
 */
@SpringBootApplication
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class,args);
    }
}

创建 src/main/java/com/lzw/springboot/mybatis/config/DruidDataSourceConfig.java

package com.lzw.springboot.mybatis.config;

import com.alibaba.druid.pool.DruidDataSource;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import javax.sql.DataSource;
import java.sql.SQLException;

/**
 * @author LiAng
 */
@Configuration
public class DruidDataSourceConfig {
    @ConfigurationProperties("spring.datasource")
    @Bean
    public DataSource dataSource() throws SQLException {
        DruidDataSource druidDataSource = new DruidDataSource();
        return druidDataSource;
    }
}

创建 src/test/java/com/lzw/springboot/mybatis/ApplicationTest.java

package com.lzw.springboot.mybatis;

import org.junit.jupiter.api.Test;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.jdbc.core.JdbcTemplate;

import javax.annotation.Resource;

/**
 * @author LiAng
 */
@SpringBootTest
public class ApplicationTest {

    @Resource
    private JdbcTemplate jdbcTemplate;

    @Test
    public void t1(){
        //输出。看下当前的数据源
        System.out.println(jdbcTemplate.getDataSource().getClass());
    }
}

测试看看数据源

创建 src/main/java/com/lzw/springboot/mybatis/bean/Monster.java

package com.lzw.springboot.mybatis.bean;

import com.fasterxml.jackson.annotation.JsonFormat;
import lombok.Data;

import java.util.Date;

/**
 * @author LiAng
 */
@Data
public class Monster {
    private Integer id;
    private Integer age;
    
    private Date birthday;
    private String email;
    private String name;
    private String gender;
    private Double salary;
}

创建 src/main/java/com/lzw/springboot/mybatis/mapper/MonsterMapper.java

package com.lzw.springboot.mybatis.mapper;

import com.lzw.springboot.mybatis.bean.Monster;
import org.apache.ibatis.annotations.Mapper;

/**
 * @author LiAng
 * 在Mapper接口使用 @Mapper 就会扫描，并将Mapper接口对象注入
 */
@Mapper
public interface MonsterMapper {
    //根据id返回Monster对象
    public Monster getMonsterById(Integer id);
}

创建 src/main/resources/mapper/MonsterMapper.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.lzw.springboot.mybatis.mapper.MonsterMapper">
    <!--配置getMonsterById-->
    <select id="getMonsterById" resultType="com.lzw.springboot.mybatis.bean.Monster">
        SELECT * FROM `monster` WHERE id=#{id}
    </select>
</mapper>

修改 application.yml

server:
  port: 9090
spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/springboot_mybatis?useSSL=true&useUnicode=true&characterEncoding=UTF-8
    username: root
    password: 123456
mybatis:
  # 指定要扫描的 mapper.xml
  mapper-locations: classpath:mapper/*.xml

修改 ApplicationTest.java

@SpringBootTest
public class ApplicationTest {
    @Resource
    private MonsterMapper monsterMapper;

    //测试MonsterMapper接口
    @Test
    public void getMonsterById(){

        Monster monster = monsterMapper.getMonsterById(1);
        System.out.println(monster);
    }
}

测试

注意事项和细节说明

spring boot 整合 mybatis 取出的日期，出现 8 小时时差解决方案

修改 Monster.java

	//这里通过注解来解决时区问题
    //GMT 就是格林尼治标准时间
    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
    private Date birthday;