1 关于SQL

1 数据源的自动配置-HikariDataSource

1 导入JDBC

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

数据库驱动, 导入JDBC场景，官方没有导入驱动, 因其不知道我们接下要操作什么数据库。

默认版本：<mysql.version>8.0.22</mysql.version>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
<!--            <version>5.1.49</version>-->
        </dependency>
想要修改版本
1、直接依赖引入具体版本（maven的就近依赖原则）
2、重新声明版本（maven的属性的就近优先原则）
    <properties>
        <java.version>1.8</java.version>
        <mysql.version>5.1.49</mysql.version>
    </properties>

2 自动配置

1 自动配置的类

• DataSourceAutoConfiguration ： 数据源的自动配置
  • 修改数据源相关的配置：spring.datasource
  • 数据库连接池的配置，是自己容器中没有DataSource才自动配置的
  • 底层配置好的连接池是：HikariDataSource

	@Configuration(proxyBeanMethods = false)
	@Conditional(PooledDataSourceCondition.class)
	@ConditionalOnMissingBean({
    
     DataSource.class, XADataSource.class })
	@Import({
    
     DataSourceConfiguration.Hikari.class, DataSourceConfiguration.Tomcat.class,
			DataSourceConfiguration.Dbcp2.class, DataSourceConfiguration.OracleUcp.class,
			DataSourceConfiguration.Generic.class, DataSourceJmxConfiguration.class })
	protected static class PooledDataSourceConfiguration{
    
    
    }

说明:

• DataSourceTransactionManagerAutoConfiguration： 事务管理器的自动配置
• JdbcTemplateAutoConfiguration： JdbcTemplate的自动配置，可以来对数据库进行crud
  • 可以修改这个配置项@ConfigurationProperties(prefix = “spring.jdbc”) 来修改JdbcTemplate
• • @Bean@Primary JdbcTemplate；容器中有这个组件
• JndiDataSourceAutoConfiguration： jndi的自动配置
• XADataSourceAutoConfiguration： 分布式事务相关的

3 修改默认配置

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/test
    username: root
    password: root
    driver-class-name: com.mysql.jdbc.Driver

4 测试

@Slf4j
@SpringBootTest
class Boot05WebAdminApplicationTests {
    
    

    @Autowired
    JdbcTemplate jdbcTemplate;


    @Test
    void contextLoads() {
    
    

//        jdbcTemplate.queryForObject("select * from t_user")
//        jdbcTemplate.queryForList("select * from t_user",)
        Long aLong = jdbcTemplate.queryForObject("select count(*) from t_user", Long.class);
        log.info("记录总数：{}",aLong);
    }

}

2 Druid数据源

1 druid的使用

1 创建数据源

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.17</version>
        </dependency>

<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource"
		destroy-method="close">
		<property name="url" value="${jdbc.url}" />
		<property name="username" value="${jdbc.username}" />
		<property name="password" value="${jdbc.password}" />
		<property name="maxActive" value="20" />
		<property name="initialSize" value="1" />
		<property name="maxWait" value="60000" />
		<property name="minIdle" value="1" />
		<property name="timeBetweenEvictionRunsMillis" value="60000" />
		<property name="minEvictableIdleTimeMillis" value="300000" />
		<property name="testWhileIdle" value="true" />
		<property name="testOnBorrow" value="false" />
		<property name="testOnReturn" value="false" />
		<property name="poolPreparedStatements" value="true" />
		<property name="maxOpenPreparedStatements" value="20" />
</bean>

2 使用官方starter

1 引入依赖

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.17</version>
        </dependency>

2 自动配置

• 扩展配置项 spring.datasource.druid

• DruidSpringAopConfiguration.class, 监控SpringBean的；配置项：spring.datasource.druid.aop-patterns

• DruidStatViewServletConfiguration.class, 监控页的配置：spring.datasource.druid.stat-view-servlet；默认开启

• DruidWebStatFilterConfiguration.class, web监控配置；spring.datasource.druid.web-stat-filter；默认开启

• DruidFilterConfiguration.class}) 所有Druid自己filter的配置

    private static final String FILTER_STAT_PREFIX = "spring.datasource.druid.filter.stat";
    private static final String FILTER_CONFIG_PREFIX = "spring.datasource.druid.filter.config";
    private static final String FILTER_ENCODING_PREFIX = "spring.datasource.druid.filter.encoding";
    private static final String FILTER_SLF4J_PREFIX = "spring.datasource.druid.filter.slf4j";
    private static final String FILTER_LOG4J_PREFIX = "spring.datasource.druid.filter.log4j";
    private static final String FILTER_LOG4J2_PREFIX = "spring.datasource.druid.filter.log4j2";
    private static final String FILTER_COMMONS_LOG_PREFIX = "spring.datasource.druid.filter.commons-log";
    private static final String FILTER_WALL_PREFIX = "spring.datasource.druid.filter.wall";

3 常见配置案例

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/test
    username: root
    password: root
    driver-class-name: com.mysql.jdbc.Driver

    druid:
      aop-patterns: com.atguigu.admin.*  #监控SpringBean
      filters: stat,wall     # 底层开启功能，stat（sql监控），wall（防火墙）

      stat-view-servlet:   # 配置监控页功能
        enabled: true
        login-username: admin
        login-password: admin
        resetEnable: false

      web-stat-filter:  # 监控web
        enabled: true
        urlPattern: /*
        exclusions: '*.js,*.gif,*.jpg,*.png,*.css,*.ico,/druid/*'


      filter:
        stat:    # 对上面filters里面的stat的详细配置
          slow-sql-millis: 1000
          logSlowSql: true
          enabled: true
        wall:
          enabled: true
          config:
            drop-table-allow: false