在springboot中使用h2数据库

一、h2数据库介绍

h2database为我们提供了十分轻量，十分快捷方便的内嵌式数据库

• H2是一个用Java开发的嵌入式数据库，它本身只是一个类库，可以直接嵌入到应用项目中。
• 可以同应用程序打包在一起发布
• 它的另一个用途是用于单元测试。启动速度快，而且可以关闭持久化功能，每一个用例执行完随即还原到初始状态
• 提供JDBC访问接口，提供基于浏览器的控制台，可以执行sql
• 免费，开源，够快
• 还方便了程序刚开始dao层单元测试测试，不需要搭建oracle，不需要加载mysql，快速测试写的dao

二、导入过程

1. 在pom.xml中导入相关依赖

<dependency><groupId>com.h2database</groupId><artifactId>h2</artifactId><scope>runtime</scope>
</dependency>
<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope>
</dependency>

2. 修改application.yml文件，加入H2相关配置

server:port: 8089
spring:datasource:url: jdbc:h2:~/testdriver-class-name: org.h2.Driverusername: sapassword: 123456#    schema: classpath:db/schema.sql
#    data: classpath:db/data.sqljpa:database: h2hibernate:ddl-auto: updateshow-sql: trueh2:console:path: /h2-consoleenabled: true

3. domain层，即Location类(entity)：

package com.springboot.demo.entity;import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;import javax.persistence.*;@Entity
@Data
@AllArgsConstructor
@NoArgsConstructor
public class Location {@Id@GeneratedValue(strategy = GenerationType.IDENTITY)private Long id;private String type;private double latitude;private double longtitude;
}

4. dao层，即LocationRepository接口：

package com.springboot.demo.repository;import com.springboot.demo.entity.Location;
import org.springframework.context.annotation.Bean;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;import java.util.List;@Repository
public interface LocationRepository extends JpaRepository<Location,Long> {List<Location> getLocationsByType(String type);
}

5. controller层，即LocationController：

package com.springboot.demo.controller;import com.springboot.demo.entity.Location;
import com.springboot.demo.repository.LocationRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.stereotype.Repository;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;import java.util.List;@Controller
public class HelloContraller {@Autowiredprivate LocationRepository locationRepository;@ResponseBody@RequestMapping("/hello")public List<Location> hello(){return locationRepository.findAll();}
}

6. 编写DemoApplication

package com.springboot.demo;import com.springboot.demo.entity.Location;
import com.springboot.demo.repository.LocationRepository;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;@SpringBootApplication
public class DemoApplication {@BeanInitializingBean saveData(LocationRepository repo){return ()->{repo.save(new Location((long) 1,"1",38.998064, 117.317267));repo.save(new Location((long)2,"2",38.997793, 117.317069));repo.save(new Location((long)3,"3",38.998006, 117.317101));repo.save(new Location((long)4,"4",38.997814, 117.317332));};}public static void main(String[] args) {SpringApplication.run(DemoApplication.class, args);}}

7. 启动项目，打开浏览器访问http://localhost:8089/hello

8. 下面使用H2控制台查看：

http://localhost:8089/h2-console

输入用户名sa，密码123456

9. 在打开的页面中点击左侧的Location。

10. 可以看到右侧显示了SQL：

SELECT * FROM USER

点击上面的Run执行。

11. 执行完毕后，可以看到下面显示了我们加入的数据。