时效提示：本文写于 2020 年，部分 API、配置和工具版本可能已经变化，参考时请以官方最新文档为准。
嵌入式数据库
技术选型 Sqlite和h2
h2建表完字段名称是大写,和原本设计思路有偏差，放弃，遂采用Sqllite
并且navicat可以编辑Sqlite，而不能编辑h2
Use in Spring Boot
整合Spring data jpa jdbcTemplate
<dependency>
<groupId>org.xerial</groupId>
<artifactId>sqlite-jdbc</artifactId>
</dependency>
<dependency>
<groupId>com.zsoltfabok</groupId>
<artifactId>sqlite-dialect</artifactId>
<version>1.0</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
spring.datasource.url=jdbc:sqlite::resource:db/sqlite/db_freyr_test.db
spring.datasource.username=
spring.datasource.password=
spring.datasource.driver-class-name=org.sqlite.JDBC
spring.jpa.database-platform=org.hibernate.dialect.SQLiteDialect
到此 jpa和jdbcTemplate 整合完毕。注意：Hibernate 方言要配在 spring.jpa.database-platform（类来自上面引入的 sqlite-dialect 依赖）；spring.datasource.platform 是用来选择初始化脚本 schema-${platform}.sql 的，填方言类名不会生效。
遇到问题总结
下面这个异常来自 Spring Data JDBC 的方言识别（DialectResolver），它不支持 SQLite。只用 JdbcTemplate 的话，去掉 spring-boot-starter-data-jdbc 依赖即可；确实要用 Spring Data JDBC 的 Repository，需要自己实现并注册一个 SQLite 的 Dialect。
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.data.relational.core.dialect.Dialect]: Factory method 'jdbcDialect' threw exception; nested exception is org.springframework.data.jdbc.repository.config.DialectResolver$NoDialectException: Cannot determine a dialect for org.springframework.jdbc.core.JdbcTemplate@51eb0e84. Please provide a Dialect.
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:185)
at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:650)
... 34 common frames omitted
Caused by: org.springframework.data.jdbc.repository.config.DialectResolver$NoDialectException: Cannot determine a dialect for org.springframework.jdbc.core.JdbcTemplate@51eb0e84. Please provide a Dialect.
at org.springframework.data.jdbc.repository.config.DialectResolver.lambda$getDialect$2(DialectResolver.java:80)
at java.util.Optional.orElseThrow(Optional.java:290)
at org.springframework.data.jdbc.repository.config.DialectResolver.getDialect(DialectResolver.java:79)
at org.springframework.data.jdbc.repository.config.AbstractJdbcConfiguration.jdbcDialect(AbstractJdbcConfiguration.java:144)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154)
... 35 common frames omitted