1. 修改pom.xml,增加druid和log4j依赖

<!--https://mvnrepository.com/artifact/com.alibaba/druid -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.21</version>
        </dependency>

        <!--druid需要log4j-->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>

2. 新建一个config包，新建DruidConfig类

package cn.boxku.config;

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

import javax.sql.DataSource;
import java.util.HashMap;

/**
 * ————————————————————————————————————————————————
 * CREATED BY since ON 2020/3/6 11:27
 * ————————————————————————————————————————————————
 */

@Configuration
public class DruidConfig {

    @ConfigurationProperties(prefix = "spring.datasource")
    @Bean
    public DataSource druidDataSource(){
        return new DruidDataSource();
    }

    @Bean
    public ServletRegistrationBean statViewServlet()
    {
        ServletRegistrationBean<StatViewServlet> bean = new ServletRegistrationBean<>(new StatViewServlet(),"/druid/*");
        HashMap<String, String> initParameters = new HashMap<>();
        //账户密码
        initParameters.put("loginUsername","admin");
        initParameters.put("loginPassword","admin");
        //允许谁访问
        initParameters.put("allow","localhost");
        //禁止谁访问
        bean.setInitParameters(initParameters);
        return bean;
    }

    @Bean
    public FilterRegistrationBean webStatFilter(){
        FilterRegistrationBean bean = new FilterRegistrationBean();
        bean.setFilter(new WebStatFilter());
        HashMap<String, String> initParameters = new HashMap<>();
        //这些不统计
        initParameters.put("exclusions","*.js,/druid/*");
        bean.setInitParameters(initParameters);
        return bean;
    }

}

3. 修改application.yml文件

spring:
  datasource:
    username: mallmall
    password: mallmall
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/mallmall? serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8
    #druid
    type: com.alibaba.druid.pool.DruidDataSource
    #Spring Boot 默认是不注入这些属性值的，需要自己绑定
    #druid 数据源专有配置
    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

    #配置监控统计拦截的filters，stat:监控统计、log4j：日志记录、wall：防御sql注入
    #如果允许时报错  java.lang.ClassNotFoundException: org.apache.log4j.Priority
    #则导入 log4j 依赖即可，Maven 地址： https://mvnrepository.com/artifact/log4j/log4j
    filters: stat,wall,log4j
    maxPoolPreparedStatementPerConnectionSize: 20
    useGlobalDataSourceStat: true
    connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=500