说明java程序很大一部分要操作数据库，为了提高性能操作数据库的时候，有不得不使用数据库连接池。数据库连接池有很多选择，c3p、dhcp、proxool等，druid作为一名后起之秀，凭借其出色的性能，也逐渐印入了大家的眼帘。接下来本教程就说一下druid的简单使用。

一、在pom.xml文件中加入druid-1.1.4.jar

<dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>druid-spring-boot-starter</artifactId>
        <version>1.1.4</version>
</dependency>

二、配置数据源

spring.datasource.druid.driverClassName=com.mysql.jdbc.Driver
spring.datasource.druid.url=jdbc:mysql://localhost:3306/demo?characterEncoding=UTF-8&useSSL=false
spring.datasource.druid.username=root
spring.datasource.druid.password=123456
spring.datasource.druid.db-type=mysql
spring.datasource.druid.initialSize=5
spring.datasource.druid.minIdle=5
spring.datasource.druid.maxActive=20
spring.datasource.druid.maxWait=60000
spring.datasource.druid.timeBetweenEvictionRunsMillis=60000
spring.datasource.druid.minEvictableIdleTimeMillis=300000
spring.datasource.druid.validationQuery=SELECT 1 FROM DUAL
spring.datasource.druid.testWhileIdle=true
spring.datasource.druid.testOnBorrow=false
spring.datasource.druid.testOnReturn=false
spring.datasource.druid.poolPreparedStatements=true
spring.datasource.druid.maxPoolPreparedStatementPerConnectionSize=20
spring.datasource.druid.filters=stat,wall,log4j,config
spring.datasource.druid.connectionProperties=druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000
spring.datasource.druid.useGlobalDataSourceStat=true
spring.datasource.druid.filter.wall.enabled=true

三、编写配置类DruidConfiguration

注意这个配置类得让spring boot加载

@Configurable
public class DruidConfiguration {

    @Bean
    public ServletRegistrationBean DruidStatViewServle2() {

        ServletRegistrationBean servletRegistrationBean = new ServletRegistrationBean(new StatViewServlet(),"/druid/*");
        //白名单
        servletRegistrationBean.addInitParameter("allow","127.0.0.1");

        //黑名单
        servletRegistrationBean.addInitParameter("deny","");

        //登陆账号
        servletRegistrationBean.addInitParameter("loginUsername","admin");
        servletRegistrationBean.addInitParameter("loginPassword","123456");
        //是否重置数据
        servletRegistrationBean.addInitParameter("resetEnable","false");
        return servletRegistrationBean;
    }

    @Bean
    public FilterRegistrationBean druidStatFilter2() {
        FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean(new WebStatFilter());
        //添加过滤规则
        filterRegistrationBean.addUrlPatterns("/*");
        // 添加不需要忽略的格式信息
        filterRegistrationBean.addInitParameter("exclusions","*.js,*.gif,*.jpg,*.png,*.css,*.ico,/druid/*");
        return filterRegistrationBean;
    }
}

启动应用就可以访问:http://localhost:18100/druid/sql.html 账号admin密码123456