Spring boot associated druid

First of all, why do we use this database connection pool? A large part of our development is around the database. When we operate on the database, we need to go in and out of the database connection pool to obtain the connection with the database. Therefore, an efficient and safe database connection pool has become our goal.
So we choose druid, which is the implementation of a database connection pool on Alibaba's open source platform.
The most niubi important thing about him is that he can realize background supervision and log monitoring. It's like hiring a housekeeper to keep an eye on the connection pool, making our pool more secure.
After talking for a long time, let's start step by step to use druid in spring boot.

Guide Package

First, of course, import our dependencies
Be sure to remember to import druid launcher!!!!

<dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.23</version>
        </dependency>
        
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.23</version>
        </dependency>       

These two packages are enough. One is druid, and the other is used by spring to start druid
The next step is to operate in the springboot configuration file

spring:
 datasource:
   username: sa
   password: 123456
   url: jdbc:mysql://localhost:3306/mysql?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8
   driver-class-name: com.mysql.jdbc.Driver
   type: com.alibaba.druid.pool.DruidDataSource
   Remember to change the type of database connection pool
   Then the following is the configuration of the database connection pool 
   If you can't identify it, it's start Question of
   
   druid:
     initialSize: 5
     minIdle: 5
     maxActive: 20
     maxWait: 60000
     timeBetweenEvictionRunsMillis: 60000
     minEvictableIdleTimeMillis: 300000
     validationQuery: SELECT 1 FROM DUAL
     testWhileIdle: true
     testOnBorrow: false
     testOnReturn: false
     poolPreparedStatements: true
     filters: stat,wall,log4j
     maxPoolPreparedStatementPerConnectionSize: 20
     useGlobalDataSourceStat: true
     connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=500







server:
 port: 8080

mybatis:
 mapper-locations:
   - classpath:dao/*.xml
   - classpath*:com/**/dao/*.xml

Once configured, you can use it. If you don't feel at ease, you can test it yourself. Because the connection pool is registered in the bean, we can directly use autowird to inject and then output the getclass of the connection pool. You can see that it has indeed been replaced with druid

Because we also need to use the built-in front-end display of the database connection pool
So we still need to customize a configuration

package com.liujiacheng.config;

import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.support.http.StatViewServlet;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import java.util.HashMap;
import java.util.Map;

/**
 * @author Michelle
 */
@Configuration
public class DruidConfig {
    @ConfigurationProperties(prefix = "spring.datasource.druid")
    @Bean
    public DruidDataSource druidDataSource() {
        return new DruidDataSource();
    }

    @Bean
    public ServletRegistrationBean statViewServlet() {
        ServletRegistrationBean bean = new ServletRegistrationBean(new StatViewServlet(), "/druid/*");

        Map<String, String> initParams = new HashMap<>();
        initParams.put("loginUsername", "admin");
        initParams.put("loginPassword", "123456");
        initParams.put("allow", "");
        bean.setInitParameters(initParams);
        return bean;
    }


}

Are some dead code, just use it directly
Then go directly when you visit
http://localhost:8080/druid/helloSql
This website can access this page