springboot2.0整合druid，以及springboot自动装配DataSource原理_Java_鸭鸭的博客-CSDN博客
1.springboot 目前的推荐版是2.1.2.RELEASE，我们就以当前最新的推荐版为例
2.创建项目，引入对应的jar包，我是以maven的形式
父级的pom
<parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.1.2.RELEASE</version> <relativePath /> <!-- lookup parent from repository --> </parent>引入的包
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-jdbc</artifactId> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>com.alibaba</groupId> <artifactId>druid-spring-boot-starter</artifactId> <version>1.1.10</version> </dependency>3.配置文件，更新详细的配置 请参考 阿里的github查看，网址；里面介绍了更详细的属性含义，以及多数据源的配置方式
spring: datasource: url: jdbc:mysql://localhost:3306/test username: root password: 613814 driver-class-name: com.mysql.jdbc.Driver type: com.alibaba.druid.pool.DruidDataSource druid: initial-size: 8 min-idle: 1 max-active: 20 max-wait: 60000 time-between-eviction-runsMillis: 60000 min-evictable-idle-timeMillis: 300000 validation-query: select 'x' FROM DUAL test-while-idle: true test-on-borrow: false test-on-return: false pool-prepared-statements: true max-open-prepared-statements: 20 max-pool-prepared-statement-per-connection-size: 20 filters: stat connection-properties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000 use-global-data-source-stat: true4.测试类，debug运行，可以看到，DataSource接口的实现类就是durid的实现类，可以继续找到配置文件中的一些初始化参数
initial-size: 8
min-idle: 1
max-active: 20
max-wait: 60000
@RunWith(SpringRunner.class)@SpringBootTest(classes = { BadgerDruidApplication.class })public class BadgerDruidApplicationTests { @Autowired DataSource dataSource; @Test public void contextLoads() throws SQLException { Connection connection = dataSource.getConnection(); PreparedStatement prepareStatement = connection .prepareStatement("select * from t_city where parent_id='-1'"); ResultSet resultSet = prepareStatement.executeQuery(); while (resultSet.next()) { String cityName = resultSet.getString("name"); System.out.println(cityName); } }}
至此，druid就与springboot2.0集成完成了；当然中间也会有springboot2.0 mysql的驱动包，跟服务端版本不匹配的异常
java.sql.SQLNonTransientConnectionException: CLIENT_PLUGIN_AUTH is required
替换下mysql驱动的版本
<properties> <java.version>1.8</java.version> <mysql.version>5.1.6</mysql.version> </properties>5.下面讲一点springboot对DataSource的一些自动装配原理，以及另一种druid的方式
spring-boot-autoconfigure-2.1.2.RELEASE.jar包下的org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration类
@Configuration@ConditionalOnClass({ DataSource.class, EmbeddedDatabaseType.class })@EnableConfigurationProperties(DataSourceProperties.class)@Import({ DataSourcePoolMetadataProvidersConfiguration.class, DataSourceInitializationConfiguration.class })public class DataSourceAutoConfiguration { @Configuration @Conditional(EmbeddedDatabaseCondition.class) @ConditionalOnMissingBean({ DataSource.class, XADataSource.class }) @Import(EmbeddedDataSourceConfiguration.class) protected static class EmbeddedDatabaseConfiguration { } @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 { } /** * {@link AnyNestedCondition} that checks that either {@code spring.datasource.type} * is set or {@link PooledDataSourceAvailableCondition} applies. */ static class PooledDataSourceCondition extends AnyNestedCondition { PooledDataSourceCondition() { super(ConfigurationPhase.PARSE_CONFIGURATION); } @ConditionalOnProperty(prefix = "spring.datasource", name = "type") static class ExplicitType { } @Conditional(PooledDataSourceAvailableCondition.class) static class PooledDataSourceAvailable { } }我们先看类上@Import({ DataSourcePoolMetadataProvidersConfiguration.class,DataSourceInitializationConfiguration.class })
DataSourcePoolMetadataProvidersConfiguration导入这个类的实例，点进去可以看到
@ConditionalOnClass(org.apache.tomcat.jdbc.pool.DataSource.class)
@ConditionalOnClass(HikariDataSource.class)
@ConditionalOnClass(BasicDataSource.class)
这3个数据源的装配，都是导入了这些数据源，才会实例创建成功；而springboot2.0的默认生效的HikariDataSource数据源；如图所示，spring-boot-starter-jdbc默认依赖了；而在springboot1.x中，默认生效的org.apache.tomcat.jdbc.pool.DataSource.class
现在我们看下根据spring.datasource.type指定类型的实例化，只拿了一部分主要的，我们主要来看PooledDataSourceConfiguration 这个内部类
@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 { }@Conditional(PooledDataSourceCondition.class) 根据判断条件，实例化这个类，指定了配置文件中，必须有type这个属性
实例化后，@Import 会导入DataSourceConfiguration 这个类；在DataSourceConfiguration这个类中，就是具体的DataSource接口实现；我们默认导入web模块后，会导入tomcat，并且实例化org.apache.tomcat.jdbc.pool.DataSource
/** * Tomcat Pool DataSource configuration. */ //只要导入了这个org.apache.tomcat.jdbc.pool.DataSource.class，就会生效 @ConditionalOnClass(org.apache.tomcat.jdbc.pool.DataSource.class) //没有DataSource的实例 @ConditionalOnMissingBean(DataSource.class) //配置了spring.datasource.type 并且值为org.apache.tomcat.jdbc.pool.DataSource，才会生效； //matchIfMissing=true表示，就算没有配置spring.datasource.type，也会生效 @ConditionalOnProperty(name = "spring.datasource.type", havingValue = "org.apache.tomcat.jdbc.pool.DataSource", matchIfMissing = true) static class Tomcat { @Bean @ConfigurationProperties(prefix = "spring.datasource.tomcat") public org.apache.tomcat.jdbc.pool.DataSource dataSource( DataSourceProperties properties) { org.apache.tomcat.jdbc.pool.DataSource dataSource = createDataSource( properties, org.apache.tomcat.jdbc.pool.DataSource.class); DatabaseDriver databaseDriver = DatabaseDriver .fromJdbcUrl(properties.determineUrl()); String validationQuery = databaseDriver.getValidationQuery(); if (validationQuery != null) { dataSource.setTestOnBorrow(true); dataSource.setValidationQuery(validationQuery); } return dataSource; } }另外springboot 默认支持 type 类型设置的数据源；
@Import({ DataSourceConfiguration.Hikari.class, DataSourceConfiguration.Tomcat.class,
DataSourceConfiguration.Dbcp2.class, DataSourceConfiguration.Generic.class,
DataSourceJmxConfiguration.class })
具体的，接着DataSourceConfiguration类看就可以了，
下面说下，集成druid 在DataSourceConfiguration类，最后的部分
/** * Generic DataSource configuration. */ @ConditionalOnMissingBean(DataSource.class) @ConditionalOnProperty(name = "spring.datasource.type") static class Generic { @Bean public DataSource dataSource(DataSourceProperties properties) { return properties.initializeDataSourceBuilder().build(); } }如果上面，都不生效，就会执行这个；我们直接看 return properties.initializeDataSourceBuilder().build(); 这个build方法；
@SuppressWarnings("unchecked") public T build() { Class<? extends DataSource> type = getType(); DataSource result = BeanUtils.instantiateClass(type); maybeGetDriverClassName(); bind(result); return (T) result; }拿到上述配置文件中的com.alibaba.druid.pool.DruidDataSource 这个类的全类名，反射实例化；至此，datasource的实例过程，就说完了；最后我们看下，阿里官方封装的druid-spring-boot-starter，直接简单粗暴的创建了一个datasource的实现，有感性的朋友，也可以看下DruidDataSourceWrapper 的具体实现，就不在继续描述
@Configuration@ConditionalOnClass(DruidDataSource.class)@AutoConfigureBefore(DataSourceAutoConfiguration.class)@EnableConfigurationProperties({DruidStatProperties.class, DataSourceProperties.class})@Import({DruidSpringAopConfiguration.class, DruidStatViewServletConfiguration.class, DruidWebStatFilterConfiguration.class, DruidFilterConfiguration.class})public class DruidDataSourceAutoConfigure { private static final Logger LOGGER = LoggerFactory.getLogger(DruidDataSourceAutoConfigure.class); @Bean(initMethod = "init") @ConditionalOnMissingBean public DataSource dataSource() { LOGGER.info("Init DruidDataSource"); return new DruidDataSourceWrapper(); }}原网址: 访问
创建于: 2020-05-06 01:31:28
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