【java web篇】MyBatis之Mapper代理

文章目录

• • • 一.引言
    • 二.Hikari
    • 三.Druid
    • 四.连接池参数

一.引言

数据库连接池负责分配、管理、释放数据库连接，它允许应用程序重复使用现有的数据连接，而不是重新创建一个。释放超过最大空间时间的数据库连接来避免因为没有释放数据库连接导致数据库连接泄漏。本文主要介绍Hikari和Druid两种数据库连接池的使用。

Hikari速度极快；但是Druid功能更加全面，支持sql级监控，扩展、SQL防注入，而且有更多、更久的生产实践、更可靠。

二.Hikari

• maven依赖

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

• 配置方式

  spring:
    datasource:
      type: com.zaxxer.hikari.HikariDataSource
      driverClassName: com.mysql.cj.jdbc.Driver
      url: jdbc:mysql://localhost:3306/blog-data?zeroDateTimeBehavior=convertToNull&useUnicode=true&characterEncoding=utf-8
      username: root
      password: 123456
      hikari:
        minimum-idle: 5
  

• HikariDataSource注入过程

  • spring-boot-autoconfigure依赖下的META-INFO/spring-factories

    org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration,
    

  • DataSourceAutoConfiguration

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

  • DataSourceConfiguration.Hikari

    @Configuration(proxyBeanMethods = false)
    //有class文件的时候执行
    	@ConditionalOnClass(HikariDataSource.class)
    //没有实例的时候执行
    	@ConditionalOnMissingBean(DataSource.class)
    //有配置的时候执行
    	@ConditionalOnProperty(name = "spring.datasource.type", havingValue = "com.zaxxer.hikari.HikariDataSource",
    			matchIfMissing = true)
    	static class Hikari {
    
    		//注入dataSource bean
    		@Bean
    		//设置HikariDataSource实例的属性
    		@ConfigurationProperties(prefix = "spring.datasource.hikari")
    		HikariDataSource dataSource(DataSourceProperties properties) {
    			HikariDataSource dataSource = createDataSource(properties, HikariDataSource.class);
    			if (StringUtils.hasText(properties.getName())) {
    				dataSource.setPoolName(properties.getName());
    			}
    			return dataSource;
    		}
    
    	}
    

三.Druid

• maven依赖

  <dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid-spring-boot-starter</artifactId>
    <version>1.1.10</version>
  </dependency>
  

• 配置方式

  spring:
    datasource:
      type: com.zaxxer.hikari.HikariDataSource
      driverClassName: com.mysql.cj.jdbc.Driver
      url: jdbc:mysql://localhost:3306/blog-data?zeroDateTimeBehavior=convertToNull&useUnicode=true&characterEncoding=utf-8
      username: root
      password: 123456
      druid:
        minimum-idle: 5
  

• DruidDataSource注入方式

  • DruidDataSourceAutoConfigure

    //调用DruidDataSource的init方法
    @Bean(
            initMethod = "init"
        )
        @ConditionalOnMissingBean
        public DataSource dataSource() {
            LOGGER.info("Init DruidDataSource");
            return new DruidDataSourceWrapper();
        }
    

  • DruidDataSourceWrapper

    @ConfigurationProperties("spring.datasource.druid")
    class DruidDataSourceWrapper extends DruidDataSource implements InitializingBean {
        @Autowired
        private DataSourceProperties basicProperties;
    
        DruidDataSourceWrapper() {
        }
    
        public void afterPropertiesSet() throws Exception {
            if (super.getUsername() == null) {
                super.setUsername(this.basicProperties.determineUsername());
            }
    
            if (super.getPassword() == null) {
                super.setPassword(this.basicProperties.determinePassword());
            }
    
            if (super.getUrl() == null) {
                super.setUrl(this.basicProperties.determineUrl());
            }
    
            if (super.getDriverClassName() == null) {
                super.setDriverClassName(this.basicProperties.getDriverClassName());
            }
    
        }
    }
    

  • DruidDataSource.init()进行参数校验

四.连接池参数