Springboot2.0以后默认数据库连接池选择了Hikari（性能高）开源地址：/brettwooldridge/HikariCP里面有技术文档
性能方面hikariCP>druid>tomcat-jdbc>dbcp>c3p0，可以参考性能对比
/qq_31125793/article/details/51241943
本文介绍配置默认的hikari，对比线程池大小设置的运行结果。
上代码。
package com.figo.master.service;import java.util.UUID;import java.util.concurrent.CountDownLatch;import org.junit.Test;import org.junit.runner.RunWith;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.boot.test.context.SpringBootTest;import org.springframework.test.context.junit4.SpringRunner;import com.alibaba.fastjson.JSONObject;import com.figo.master.service.impl.OrderServiceImpl;@RunWith(SpringRunner.class)@SpringBootTestpublic class DbConnectionPoolTest {@Autowiredprivate OrderServiceImpl orderService;int orderTime = 1000;int time = 10;// 循环10次long totalConsumeTime = 0;// 总耗时时间@Testpublic void dbConnPoolTest() throws Exception {for (int i = 0; i < time; i++) {CountDownLatch cdlTime = new CountDownLatch(orderTime);CountDownLatch cdl = new CountDownLatch(1);Long begin = System.currentTimeMillis();for (int a = 0; a < orderTime; a++) {// 生成订单信息Thread thread = new Thread(new OrderRun(cdl,cdlTime));thread.start();}cdl.countDown();cdlTime.await();Long end = System.currentTimeMillis();totalConsumeTime = totalConsumeTime + (end - begin);System.out.println(orderTime + "笔订单，总耗时=" + ((end - begin) / 1000) + "秒");}System.out.println(time * orderTime + "笔订单，总耗时=" + (totalConsumeTime / 1000) + "秒");// 单元测试不支持多线程，需要sleepThread.sleep(300000);}public class OrderRun implements Runnable {CountDownLatch cdlNew;CountDownLatch cdlTimeNew;public OrderRun(CountDownLatch cdl,CountDownLatch cdlTime) {this.cdlNew = cdl;this.cdlTimeNew=cdlTime;}@Overridepublic void run() {try {cdlNew.await();} catch (InterruptedException e1) {// TODO Auto-generated catch blocke1.printStackTrace();}JSONObject orderinfo = new JSONObject();Long timeStamp = System.currentTimeMillis();String uuidString = UUID.randomUUID().toString();orderinfo.put("order_id", timeStamp + uuidString);orderinfo.put("user_id", timeStamp + uuidString);orderinfo.put("good_id", timeStamp + uuidString);try {orderService.createOrder(orderinfo);cdlTimeNew.countDown();} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}}}}
数据库写订单，跑了10次，每次并发1000笔，数据库连接池属性如下：
#datasource
spring.datasource.url=jdbc:mysql://192.160.0.12:3306/master?useSSL=false
spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
#0718配置连接池
# Hikari will use the above plus the following to setup connection pooling
spring.datasource.type=com.zaxxer.hikari.HikariDataSource
spring.datasource.hikari.minimum-idle=2
spring.datasource.hikari.maximum-pool-size=20
spring.datasource.hikari.auto-commit=true
spring.datasource.hikari.idle-timeout=30000
spring.datasource.hikari.pool-name=DatebookHikariCP
spring.datasource.hikari.max-lifetime=1800000
spring.datasource.hikari.connection-timeout=30000
spring.datasource.hikari.connection-test-query=SELECT 1
试验发现spring.datasource.hikari.maximum-pool-size=10，耗时24秒，设置为20耗时12秒，另外如果把hikari相关的属性删除，发现springboot会默认安排连接池大小，我试验下来，会安排10个左右，不会说1000个并发，就创建1000个连接，所以建议还是根据应用程序服务器和数据库服务器性能，进行hikari属性的配置。
