配置文件 :
spring boot 配置文件 有两种形式 ,一种是properties文件、一种是yml文件。案列使用properties文件。
数据源的默认配置 :
spring boot 约定优先于配置 ,所以数据源也有默认的配置,所有的默认配置文件基本都已xxxautoConfiguration.java 的形式放在spring-boot-configure.jar中,配置在“/META-INF/spring.factories”文件中 。数据源的默认配置类为:org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration ,在配置文件中导入了四中配置,黄色标记部分,如下
@Configuration
@ConditionalOnClass({ DataSource.class, EmbeddedDatabaseType.class })
@EnableConfigurationProperties(DataSourceProperties.class)
@Import({ DataSourcePoolMetadataProvidersConfiguration.class, DataSourceInitializationConfiguration.class })
public class DataSourceAutoConfiguration {
...
@Configuration
@Conditional(PooledDataSourceCondition.class)
@ConditionalOnMissingBean({ DataSource.class, XADataSource.class })
@Import({ DataSourceConfiguration.Hikari.class, DataSourceConfiguration.Tomcat.class,
DataSourceConfiguration.Dbcp2.class, DataSourceConfiguration.Generic.class,
DataSourceJmxConfiguration.class })
protected static class PooledDataSourceConfiguration {
}
...
}
而从DataSourceBuilder类代码看 ,知道 ,会去遍历加载,这个四个数据源,如果加载成功了,就返回,后面的不再加载。
public final class DataSourceBuilder<T extends DataSource> {
private static final String[] DATA_SOURCE_TYPE_NAMES = new String[] { "com.zaxxer.hikari.HikariDataSource",
"org.apache.tomcat.jdbc.pool.DataSource", "org.apache.commons.dbcp2.BasicDataSource" };
...
@SuppressWarnings("unchecked")
public static Class<? extends DataSource> findType(ClassLoader classLoader) {
for (String name : DATA_SOURCE_TYPE_NAMES) {
try {
//加载成功便会返回。
return (Class<? extends DataSource>) ClassUtils.forName(name, classLoader);
}
catch (Exception ex) {
// Swallow and continue
}
}
return null;
}
...
}
看看我们Pom文件导入的数据源jar包,点击后跟踪到最后一个pom文件 ,看到只导入了HikariCP数据源。
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jdbc</artifactId>
<version>2.1.6.RELEASE</version>
</dependency>
<?xml version="1.0" encoding="UTF-8"?>
<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starters</artifactId>
<version>2.1.6.RELEASE</version>
</parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jdbc</artifactId>
<version>2.1.6.RELEASE</version>
<name>Spring Boot JDBC Starter</name>
<description>Starter for using JDBC with the HikariCP connection pool</description>
<url>https://projects.spring.io/spring-boot/#/spring-boot-parent/spring-boot-starters/spring-boot-starter-jdbc</url>
<organization>
<name>Pivotal Software, Inc.</name>
<url>https://spring.io</url>
</organization>
<licenses>
<license>
<name>Apache License, Version 2.0</name>
<url>https://www.apache.org/licenses/LICENSE-2.0</url>
</license>
</licenses>
<developers>
<developer>
<name>Pivotal</name>
<email>info@pivotal.io</email>
<organization>Pivotal Software, Inc.</organization>
<organizationUrl>https://www.spring.io</organizationUrl>
</developer>
</developers>
<scm>
<connection>scm:git:git://github.com/spring-projects/spring-boot.git/spring-boot-starters/spring-boot-starter-jdbc</connection>
<developerConnection>scm:git:ssh://git@github.com/spring-projects/spring-boot.git/spring-boot-starters/spring-boot-starter-jdbc</developerConnection>
<url>https://github.com/spring-projects/spring-boot/spring-boot-starters/spring-boot-starter-jdbc</url>
</scm>
<issueManagement>
<system>Github</system>
<url>https://github.com/spring-projects/spring-boot/issues</url>
</issueManagement>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
<version>2.1.6.RELEASE</version>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>com.zaxxer</groupId>
<artifactId>HikariCP</artifactId>
<version>3.2.0</version>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>5.1.8.RELEASE</version>
<scope>compile</scope>
</dependency>
</dependencies>
</project>
根据代码分析,默认数据源配置就是 HikariCP ,注意,如果,不另外导入jar包,而配置另外的数据源 如:spring.datasource.type = org.apache.tomcat.jdbc.pool.DataSource,则会报错。
配置自定义数据源:
1.导入Druid maven 坐标
<!-- https://mvnrepository.com/artifact/com.alibaba/druid -->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.1.16</version>
</dependency>
1.以配置druid 数据源为例 ,驱动为mysql 。写入配置文件 :
spring.datasource.name = root
spring.datasource.password = 123456
spring.datasource.url = jdbc:mysql://192.168.1.103:3306/jdbc
spring.datasource.driverClassName = com.mysql.jdbc.Driver
spring.datasource.type = com.alibaba.druid.pool.DruidDataSource
3.指定配置type后还不够,数据源已切换过来 ,一下DruidConfig为配置别的属性,不写别的属性配置不进去。
@Configuration
public class DruidConfig {
@ConfigurationProperties(prefix = "spring.datasource")
@Bean
public DataSource druid(){
return new DruidDataSource();
}
//配置Druid的监控
//1、配置一个管理后台的Servlet
@Bean
public ServletRegistrationBean statViewServlet(){
ServletRegistrationBean bean = new ServletRegistrationBean(new StatViewServlet(), "/druid/*");
Map<String,String> initParams = new HashMap<>();
initParams.put("loginUsername","admin");
initParams.put("loginPassword","123456");
initParams.put("allow","");//默认就是允许所有访问
initParams.put("deny","192.168.15.21");
bean.setInitParameters(initParams);
return bean;
}
//2、配置一个web监控的filter
@Bean
public FilterRegistrationBean webStatFilter(){
FilterRegistrationBean bean = new FilterRegistrationBean();
bean.setFilter(new WebStatFilter());
Map<String,String> initParams = new HashMap<>();
initParams.put("exclusions","*.js,*.css,/druid/*");
bean.setInitParameters(initParams);
bean.setUrlPatterns(Arrays.asList("/*"));
return bean;
}
}
4.测试: