本次实验我准备使用H2数据库,虽然我现在有足够多的脚本快速启动一个MySQL、PG,但是这毕竟会增加我下次启动该项目时的时间成本。H2数据库用于技术验证是非常不错的,可以将代码和数据库集中在一个项目中,很有研究价值,所以我决定使用H2数据库,顺便积累这个数据的使用经验。
准备工作
引入依赖
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<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<dependency>
<groupId>com.baomidou</groupId>
<artifactId>mybatis-plus-boot-starter</artifactId>
<version>3.4.3.1</version>
</dependency>
<dependency>
<groupId>com.h2database</groupId>
<artifactId>h2</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.18.20</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</dependency>
</dependencies>
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进行配置
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spring:
application:
name: mybatis
datasource:
schema: classpath:h2/schema.sql
data: classpath:h2/data.sql
username: san
password:
driver-class-name: org.h2.Driver
url: jdbc:h2:file:~/test
h2:
console:
enabled: true
path: /h2-console
settings:
web-allow-others: true
trace: true
mybatis-plus:
mapper-locations: classpath:mapper/*Mapper.xml
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开发Entity和Mapper
User.java
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package fun.junjie.mybatis.entity;
import com.baomidou.mybatisplus.annotation.TableName;
import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;
@Data
@Builder
@NoArgsConstructor
@AllArgsConstructor
@TableName("t_user")
public class User {
/**
* 主键
*/
private String id;
/**
* 用户名
*/
private String name;
}
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UserMapper.java
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package fun.junjie.mybatis.mapper;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import fun.junjie.mybatis.entity.User;
import org.springframework.stereotype.Repository;
@Repository
public interface UserMapper extends BaseMapper<User> {
}
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准备schema.sql和data.sql
schema.sql
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DROP TABLE t_user;
CREATE TABLE t_user (
id varchar(100) PRIMARY KEY NOT NULL,
name varchar(100) NOT NULL
);
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data.sql
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INSERT INTO t_user VALUES ('1000', 'zhansan')
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测试工作
测试MyBatis-Plus集成是否生效
测试代码如下:
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package fun.junjie.mybatis.mapper;
import fun.junjie.mybatis.entity.User;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
@SpringBootTest
class UserMapperTest {
@Autowired
private UserMapper userMapper;
@Test
void selectById() {
User user = userMapper.selectById("1000");
System.out.println("");
}
}
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断点发现,user正确的获取到值了,说明h2、MyBatis的集成是有效的。
测试mapper.xml文件能否正常使用
修改UserMapper文件,代码如下:
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@Repository
public interface UserMapper extends BaseMapper<User> {
User selectByIdCustom(String userId);
}
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开发相应的mapper.xml文件,代码如下:
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<?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="fun.junjie.mybatis.mapper.UserMapper">
<select id="selectByIdCustom" resultType="fun.junjie.mybatis.entity.User">
SELECT * FROM t_user WHERE id = #{userId}
</select>
</mapper>
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开发相应的测试方法:
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@Test
void selectByIdCustom() {
User user = userMapper.selectByIdCustom("1000");
System.out.println("");
}
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断点发现,最后获取的数据是我需要的。
截止到目前,我已经完成了基础的实验环境搭建,接下将一一实现我的实验目标。