SpringBoot实践之---H2·连接数据库

原文地址：springboot整合H2内存数据库，实现单元测试与数据库无关性

一、新建spring boot工程

新建工程的时候，需要加入JPA，H2依赖

二、工程结构

pom文件依赖如下：

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>4.0.0modelVersion>

    <groupId>com.chhliu.springboot.h2groupId>
    <artifactId>springboot-h2artifactId>
    <version>0.0.1-SNAPSHOTversion>
    <packaging>jarpackaging>

    <name>springboot-h2name>
    <description>Demo project for Spring Boot H2description>

    <parent>
        <groupId>org.springframework.bootgroupId>
        <artifactId>spring-boot-starter-parentartifactId>
        <version>1.4.3.RELEASEversion>
        <relativePath/>
    parent>

    <properties>
        <project.build.sourceEncoding>UTF-8project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8project.reporting.outputEncoding>
        <java.version>1.7java.version>
    properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-data-jpaartifactId>
        dependency>
        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-webartifactId>
        dependency>

        <dependency>
            <groupId>com.h2databasegroupId>
            <artifactId>h2artifactId>
            <scope>runtimescope>
        dependency>
        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-testartifactId>
            <scope>testscope>
        dependency>
    dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.bootgroupId>
                <artifactId>spring-boot-maven-pluginartifactId>
            plugin>
        plugins>
    build>
project>

三、编写实体类

package com.chhliu.springboot.h2.entity;

import java.math.BigDecimal;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

@Entity
public class User {
  @Id
  @GeneratedValue(strategy = GenerationType.AUTO)
  private Long id;

  @Column
  private String username;

  @Column
  private String name;

  @Column
  private Short age;

  @Column
  private BigDecimal balance;

  ……省略gettter和setter方法
}

四、编写dao

package com.chhliu.springboot.h2.repository;

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

import com.chhliu.springboot.h2.entity.User;

@Repository
public interface UserRepository extends JpaRepository {

}

五、编写controller

package com.chhliu.springboot.h2.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;

import com.chhliu.springboot.h2.entity.User;
import com.chhliu.springboot.h2.repository.UserRepository;

@RestController
public class UserController {

  @Autowired
  private UserRepository userRepository;

  @GetMapping("/user/{id}")// 注意，此处使用的是GetMapping注解，该注解的作用类似与@RequestMapping(value="/user/{id}" ,method=RequestMethod.GET)，@PostMapping注解同理
  public User findById(@PathVariable Long id) {
    return this.userRepository.findOne(id);
  }
}

六、配置文件

# 服务器端口号
server.port=7900
# 是否生成ddl语句
spring.jpa.generate-ddl=false
# 是否打印sql语句
spring.jpa.show-sql=true
# 自动生成ddl，由于指定了具体的ddl，此处设置为none
spring.jpa.hibernate.ddl-auto=none
# 使用H2数据库
spring.datasource.platform=h2
# 指定生成数据库的schema文件位置
spring.datasource.schema=classpath:schema.sql
# 指定插入数据库语句的脚本位置
spring.datasource.data=classpath:data.sql
# 配置日志打印信息
logging.level.root=INFO
logging.level.org.hibernate=INFO
logging.level.org.hibernate.type.descriptor.sql.BasicBinder=TRACE
logging.level.org.hibernate.type.descriptor.sql.BasicExtractor=TRACE
logging.level.com.itmuch=DEBUG

七、启动程序

在浏览器中输入如下URL：

http://localhost:7900/user/4

可以看到测试结果

{"id":4,"username":"user4","name":"马六","age":20,"balance":100.00}

说明，我们的整合是OK的

八、测试dao层

package com.chhliu.springboot.h2;

import org.junit.Assert;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

import com.chhliu.springboot.h2.entity.User;
import com.chhliu.springboot.h2.repository.UserRepository;

@RunWith(SpringRunner.class)
@SpringBootTest
public class SpringbootH2ApplicationTests {

    @Autowired
    private UserRepository repository;

    @Test
    public void test(){
        User u = repository.findOne(1L);
        Assert.assertEquals("成功的测试用例", "张三", u.getName());
    }
}

发现测试是ok的！

九、总结

由于H2是关系内存数据库，当程序启动的时候，会在内存中创建表，并将数据存储在内存中，当重启程序后，会自动删除内存中的数据，从而可以很好的用来做dao层的单元测试和service层的单元测试，使整个程序不会依赖具体的数据库，同时也提高了单元测试的效率。