DB

MySQL

dependency

<dependencies>
  <dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
  </dependency>
</dependencies>
<build>
  <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <!--包含任意包下的任意名字的xml文件-->
                    <include>**/*.xml</include>
                </includes>
            </resource>
            <resource>
                <!--将原本的资源目录引入-->
                <directory>src/main/resources</directory>
            </resource>
        </resources>
</build>

config

spring.datasource.url=jdbc:mysql://localhost:3306/database_name?setUnicode=true&characterEncoding=UTF-8&autoReconnect=true&allowMultiQueries=true&serverTimezone=GMT%2B8
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.username=root
spring.datasource.password=123456

H2

h2是一个非常方便的嵌入式数据库

dependency

<dependency>
  <groupId>com.h2database</groupId>
  <artifactId>h2</artifactId>
</dependency>

config

url的设置决定了该数据库的属性
格式：jdbc:h2::;MODE=<? COMPATIBILITY_TYPE>;USER=

• 模式选择
  • 内存：jdbc:h2:mem:test_db
  • 嵌入：jdbc:h2:file:E:/IdeaProjects/mybatis/db/test_db
• 语法兼容性选择
  • MYSQL：jdbc:h2:mem:test_db;MODE=MySQL
  • ORACLE：jdbc:h2:mem:test_db;MODE=ORACLE
  • PostgreSQL：jdbc:h2:mem:test_db;MODE=PostgreSQL
• DATABASE_TO_LOWER：默认情况下，表是大写的，使用该参数是得表名变成小写
  • jdbc:h2:mem:test_db;MODE=MySQL;DATABASE_TO_LOWER=TRUE

    spring.datasource.url=jdbc:h2:mem:jpa
    # 开启web client
    spring.h2.console.enabled=true
    spring.h2.console.settings.trace=true
    spring.h2.console.settings.web-allow-others=true
    spring.h2.console.path=/h2-console

framework

mybatis

dependency

<dependencies>
  <dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>2.2.0</version>
  </dependency>
</dependencies>
<build>
  <resources>
    <!--默认情况下，spring不扫描java目录下的xml文件，所以如果要在java目录添加xml文件，需要额外添加此配置-->
    <resource>
      <directory>src/main/java</directory>
      <includes>
        <!--包含任意包下的任意名字的xml文件-->
        <include>**/*.xml</include>
      </includes>
    </resource>
    <resource>
      <!--将原本的资源目录引入-->
      <directory>src/main/resources</directory>
    </resource>
  </resources>
</build>

config

mybatis.mapper-locations=classpath:/mapper/*.xml

@Configuration
@MapperScan(basePackages = "com.jac.mapper")
public class MybatisConfigure {
}

mybatis-plus

dependency

<dependency>
  <groupId>com.baomidou</groupId>
  <artifactId>mybatis-plus-boot-starter</artifactId>
  <version>3.4.3.1</version>
</dependency>

config

• mybatis-plus不需要额外配置mapper-locations

  @Configuration
  @MapperScan(basePackages = "com.jac.mapper")
  public class MybatisConfigure {
  }

  JPA

  dependency

  <dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-data-jpa</artifactId>
  </dependency>

  config

  # 自动建表，如有需要，更新表结构；只会新增字段，不会删除字段
  spring.jpa.hibernate.ddl-auto=update
  # 打印sql日志
  spring.jpa.show-sql=true

  Pool

  HikariCP

  SpringBoot 2.x默认使用的连接池（1.x使用的是tomcat.jdbc.pool.DataSource）

  dependency

  SpringBoot 2.x无需配置

  <dependency>
  <groupId>com.zaxxer</groupId>
  <artifactId>HikariCP</artifactId>
  </dependency>

  config

  ```

  仅1.x需要此配置

  spring.datasource.type=com.zaxxer.hikari.HikariDataSource

其他配置

最小空闲连接，默认为10

spring.datasource.hikari.minimum-idle=10

最大连接数

spring.datasource.hikari.maximum-pool-size=20

空闲连接超时时间，默认为10分钟（单位是毫秒）

spring.datasource.hikari.idle-timeout=600000

连接最大存活时间，默认是30min，应该小于数据库设置的最大超时时间

spring.datasource.hikari.max-lifetime=18000000

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## Druid
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### dependency
```xml
<dependency>
  <groupId>com.alibaba</groupId>
  <artifactId>druid</artifactId>
  <version>1.1.16</version>
</dependency>
<!--或者-->
<dependency>
  <groupId>com.alibaba</groupId>
  <artifactId>druid-spring-boot-starter</artifactId>
  <version>1.1.10</version>
</dependency>

config

# 如果使用starter，则不需要该配置
spring.datasource.type=spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
# 其他配置
spring.datasource.druid.initial-size=
spring.datasource.druid.max-active=
spring.datasource.druid.min-idle=
spring.datasource.druid.max-wait=