扣丁学堂Java培训之Spring Boot如何使用HikariCP连接池详解

2019-03-11 14:38:43 1289浏览

今天扣丁学堂Java培训老师给大家介绍一下关于SpringBoot如何使用HikariCP连接池的相关资料，文中通过示例代码介绍的非常详细，首先Springboot让Java开发更加美好，更加简洁，更加简单。SpringBoot2.x中使用HikariCP作为默认的数据连接池。HikariCP使用Javassist字节码操作库来实现动态代理，优化并精简了字节码，同时内部使用com.zaxxer.hikari.util.FastList代替ArrayList、使用了更好的并发集合类com.zaxxer.hikari.util.ConcurrentBag，“号称”是目前最快的数据库连接池。

基本使用

在SpringBoot2.x中使用HikariCP十分简单，只需引入依赖implementation'org.springframework.boot:spring-boot-starter-jdbc'：

pluginManagement {
    repositories {
        gradlePluginPortal()
    }
}
rootProject.name = 'datasource-config'
 
plugins {
    id 'org.springframework.boot' version '2.1.3.RELEASE'
    id 'java'
}
 
apply plugin: 'io.spring.dependency-management'
 
group = 'spring-boot-guides'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '1.8'
 
repositories {
    mavenCentral()
}
 
dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-jdbc'
    runtimeOnly 'com.h2database:h2'
    testImplementation 'org.springframework.boot:spring-boot-starter-test'
}

配置文件如下：

spring:
 datasource:
 url: jdbc:h2:mem:demodb
 username: sa
 password:
 hikari: # https://github.com/brettwooldridge/HikariCP (uses milliseconds for all time values)
 maximumPoolSize: 10
 minimumIdle: 2
 idleTimeout: 600000
 connectionTimeout: 30000
 maxLifetime: 1800000

示例代码如下：

package springbootguides.datasourceconfig;
 
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
 
import javax.sql.DataSource;
import java.sql.Connection;
 
@SpringBootApplication
public class DatasourceConfigApplication implements CommandLineRunner {
 
    @Autowired
    private DataSource datasource;
 
    @Override
    public void run(String... args) throws Exception {
        try(Connection conn = datasource.getConnection()) {
            System.out.println(conn);
        }
    }
 
    public static void main(String[] args) {
        SpringApplication.run(DatasourceConfigApplication.class, args);
    }
 
}

实现原理

SpringBoot使用如下方式整合HikariCP：入口是org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration，通过org.springframework.boot.autoconfigure.jdbc.DataSourceConfiguration.Hikari中的@Bean方式创建com.zaxxer.hikari.HikariDataSource：

/**
     * Hikari DataSource configuration.
     */
    @ConditionalOnClass(HikariDataSource.class)
    @ConditionalOnMissingBean(DataSource.class)
    @ConditionalOnProperty(name = "spring.datasource.type", havingValue = "com.zaxxer.hikari.HikariDataSource", matchIfMissing = true)
    static class Hikari {
 
        @Bean
        @ConfigurationProperties(prefix = "spring.datasource.hikari")
        public HikariDataSource dataSource(DataSourceProperties properties) {
            HikariDataSource dataSource = createDataSource(properties,
                    HikariDataSource.class);
            if (StringUtils.hasText(properties.getName())) {
                dataSource.setPoolName(properties.getName());
            }
            return dataSource;
        }
 
    }

@ConfigurationProperties(prefix="spring.datasource.hikari")会自动把spring.datasource.hikari.*相关的连接池配置信息注入到创建的HikariDataSource实例中。

HikariCP的监控和遥测

因为在我们的微服务体系中使用的监控系统是Prometheus，这里以Prometheus为例。

注意springboot2.0对springboot1.x的metrics进行了重构，不再向后兼容，主要是在spring-boot-acutator中使用了micrometer，支持了更多的监控系统：Atlas、Datadog、Ganglia、Graphite、Influx、JMX、NewRelic、Prometheus、SignalFx、StatsD、Wavefront。Springboot2.0的metrics对比springboot1.x除了引入micrometer外，更大的体现是支持了tag，这也说明Prometheus、Influx等支持Tag的时序监控数据模型的监控系统已经成为主流。

在前面示例中的build.gradle中加入如下依赖：

implementation 'org.springframework.boot:spring-boot-starter-web'
implementation 'org.springframework.boot:spring-boot-starter-actuator'
implementation 'io.micrometer:micrometer-registry-prometheus'

配置文件applycation.yaml中加入对actuator的配置：

management:
 endpoints:
 web:
  exposure:
  include: "health,info,prometheus"
 server:
 port: 8079
 servlet:
  context-path: /

注意这里引入了web和actuator依赖，通过配置management.server.port指定actuator的web端点为8089端口，通过management.endpoints.include对外开放/actuator/prometheus，在引入io.micrometer:micrometer-registry-prometheus依赖之后，端点/actuator/prometheus当即生效。

curl http://localhost:8079/actuator/prometheus | grep hikari
# TYPE hikaricp_connections_acquire_seconds summary
hikaricp_connections_acquire_seconds_count{pool="HikariPool-1",} 3.0
hikaricp_connections_acquire_seconds_sum{pool="HikariPool-1",} 0.001230082
# HELP hikaricp_connections_acquire_seconds_max Connection acquire time
# TYPE hikaricp_connections_acquire_seconds_max gauge
hikaricp_connections_acquire_seconds_max{pool="HikariPool-1",} 0.0
# HELP hikaricp_connections_min Min connections
# TYPE hikaricp_connections_min gauge
hikaricp_connections_min{pool="HikariPool-1",} 2.0
# TYPE hikaricp_connections_timeout_total counter
hikaricp_connections_timeout_total{pool="HikariPool-1",} 0.0
# HELP hikaricp_connections_pending Pending threads
# TYPE hikaricp_connections_pending gauge
hikaricp_connections_pending{pool="HikariPool-1",} 0.0
# HELP hikaricp_connections_usage_seconds Connection usage time
# TYPE hikaricp_connections_usage_seconds summary
hikaricp_connections_usage_seconds_count{pool="HikariPool-1",} 3.0
hikaricp_connections_usage_seconds_sum{pool="HikariPool-1",} 0.06
# HELP hikaricp_connections_usage_seconds_max Connection usage time
# TYPE hikaricp_connections_usage_seconds_max gauge
hikaricp_connections_usage_seconds_max{pool="HikariPool-1",} 0.0
# HELP hikaricp_connections_max Max connections
# TYPE hikaricp_connections_max gauge
hikaricp_connections_max{pool="HikariPool-1",} 10.0
# HELP hikaricp_connections Total connections
# TYPE hikaricp_connections gauge
hikaricp_connections{pool="HikariPool-1",} 2.0
# HELP hikaricp_connections_creation_seconds_max Connection creation time
# TYPE hikaricp_connections_creation_seconds_max gauge
hikaricp_connections_creation_seconds_max{pool="HikariPool-1",} 0.0
# HELP hikaricp_connections_creation_seconds Connection creation time
# TYPE hikaricp_connections_creation_seconds summary
hikaricp_connections_creation_seconds_count{pool="HikariPool-1",} 1.0
hikaricp_connections_creation_seconds_sum{pool="HikariPool-1",} 0.001
# HELP hikaricp_connections_idle Idle connections
# TYPE hikaricp_connections_idle gauge
hikaricp_connections_idle{pool="HikariPool-1",} 2.0
# HELP hikaricp_connections_active Active connections
# TYPE hikaricp_connections_active gauge
hikaricp_connections_active{pool="HikariPool-1",} 0.0

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