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

直接添加Hikaricp包就可以

          <dependency>
            <groupId>com.zaxxer</groupId>
            <artifactId>HikariCP</artifactId>
            <version>3.1.0</version>
        </dependency>

反之使用jdbc包的要去除掉tomcat的连接配置

 <!-- JDBC连接数据库，因为要用HikariCP，所以需要将SpringBoot中的tomcat-jdbc排除 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>org.apache.tomcat</groupId>
                    <artifactId>tomcat-jdbc</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <!-- HikariCP 连接池依赖，从父依赖获取额版本 -->
        <dependency>
            <groupId>com.zaxxer</groupId>
            <artifactId>HikariCP</artifactId>
            <!-- <scope>runtime</scope> -->
        </dependency> 

2.添加配置：

spring.datasource.url=jdbc:mysql://127.0.0.1:3306/test1?useUnicode=true&characterEncoding=UTF-8&zeroDateTimeBehavior=convertToNull
spring.datasource.username=root
spring.datasource.password=hongda$123456
spring.datasource.driverClassName=com.mysql.jdbc.Driver
spring.datasource.max-idle=10
spring.datasource.max-active=15
spring.datasource.max-lifetime=86430000
spring.datasource.log-abandoned=true
spring.datasource.remove-abandoned=true
spring.datasource.remove-abandoned-timeout=60
spring.datasource.initialize=false
spring.datasource.sqlScriptEncoding=UTF-8

DataSourceConfig:

import com.zaxxer.hikari.HikariConfig;
import com.zaxxer.hikari.HikariDataSource;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import javax.sql.DataSource;
 * HikariCP连接池配置
@Configuration
public class DataSourceConfig {
    @Value("${spring.datasource.url}")
    private String dataSourceUrl;
    @Value("${spring.datasource.username}")
    private String user;
    @Value("${spring.datasource.password}")
    private String password;
    @Bean
    public DataSource dataSource() {
        HikariConfig config = new HikariConfig();
        config.setJdbcUrl(dataSourceUrl); //数据源
        config.setUsername(user); //用户名
        config.setPassword(password); //密码
        config.addDataSourceProperty("cachePrepStmts", "true"); //是否自定义配置，为true时下面两个参数才生效
        config.addDataSourceProperty("prepStmtCacheSize", "250"); //连接池大小默认25，官方推荐250-500
        config.addDataSourceProperty("prepStmtCacheSqlLimit", "2048"); //单条语句最大长度默认256，官方推荐2048
        config.addDataSourceProperty("useServerPrepStmts", "true"); //新版本MySQL支持服务器端准备，开启能够得到显著性能提升
        config.addDataSourceProperty("useLocalSessionState", "true");
        config.addDataSourceProperty("useLocalTransactionState", "true");
        config.addDataSourceProperty("rewriteBatchedStatements", "true");
        config.addDataSourceProperty("cacheResultSetMetadata", "true");
        config.addDataSourceProperty("cacheServerConfiguration", "true");
        config.addDataSourceProperty("elideSetAutoCommits", "true");
        config.addDataSourceProperty("maintainTimeStats", "false");
        HikariDataSource ds = new HikariDataSource(config);
        return ds;
https://gitee.com/mirrors/hikaricp
http://fanlychie.github.io/post/spring-boot-tomcat-pool-hikaricp-dbcp-dbcp2.html
https://www.jianshu.com/p/f728e8c131a9
https://blog.csdn.net/chen15369337607/article/details/78142751
http://blog.didispace.com/Springboot-2-0-HikariCP-default-reason/
https://my.oschina.net/u/3452433/blog/1607850