SpringBoot整合Druid连接池

        SpringBoot 1.x版本默认使用的的tomcat的jdbc连接池。前期快速开发并没有采用更好的连接池。由于jdbc性能，稳定性，监控能力都不如druid连接池，所以将连接池更改为druid连接池。不过在SpringBoot 2.x版本后 默认连接池已经替换成了HikariCP，由于HikariCP性能强、速度快、口碑好、代码少和稳定，暂时不推荐替换成成其他连接池。

1.引入依赖

<dependency>  
    <groupId>com.alibaba</groupId>  
    <artifactId>druid</artifactId>  
    <version>1.1.5</version>  
</dependency>

2.配置信息

在application.properties配置文件中加入druid配置

spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
spring.datasource.url=jdbc:mysql://localhost:3306?allowMultiQueries=true&autoReconnect=true
spring.datasource.username=root
spring.datasource.password=3718900
spring.datasource.driverClassName=com.mysql.jdbc.Driver
#dataSource Pool configuration
# 初始化大小
spring.datasource.initialSize=5
# 最小
spring.datasource.minIdle=5
# 最大
spring.datasource.maxActive=20
# 配置获取连接等待超时的时间
spring.datasource.maxWait=60000
# 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒
spring.datasource.timeBetweenEvictionRunsMillis=60000
# 配置一个连接在池中最小生存的时间，单位是毫秒
spring.datasource.minEvictableIdleTimeMillis=300000
# 校验SQL，Oracle配置 spring.datasource.validationQuery=SELECT 1 FROM DUAL，如果不配validationQuery项，则下面三项配置无用
spring.datasource.validationQuery=SELECT 'x'
spring.datasource.testWhileIdle=true
spring.datasource.testOnBorrow=false
spring.datasource.testOnReturn=false
# 打开PSCache，并且指定每个连接上PSCache的大小
spring.datasource.poolPreparedStatements=true
spring.datasource.maxPoolPreparedStatementPerConnectionSize=20
# 配置监控统计拦截的filters，去掉后监控界面sql无法统计，'wall'用于防火墙
spring.datasource.filters=stat,wall,log4j
# 通过connectProperties属性来打开mergeSql功能；慢SQL记录
spring.datasource.connectionProperties=druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000
# 合并多个DruidDataSource的监控数据
spring.datasource.useGlobalDataSourceStat=true

3.配置WebFilter

package com.example.durid.filter;

import com.alibaba.druid.support.http.WebStatFilter;

import javax.servlet.annotation.WebFilter;
import javax.servlet.annotation.WebInitParam;

/**
 * 配置监控拦截器
 * druid监控拦截器
 * @ClassName: DruidStatFilter
 * @author 16437
 * @date 2018年6月4日 20:53:07
 */
@WebFilter(filterName = "druidWebStatFilter",
        urlPatterns = "/*",
        initParams =
                // 忽略资源
                { @WebInitParam(name = "exclusions", value = "*.js,*.gif,*.jpg,*.bmp,*.png,*.css,*.ico,/druid/*")}
)
public class DruidStatFilter extends WebStatFilter {

}

4.配置WebServlet

package com.example.durid.base;

import com.alibaba.druid.support.http.StatViewServlet;

import javax.servlet.annotation.WebInitParam;
import javax.servlet.annotation.WebServlet;

/**
 * druid监控视图配置
 * @ClassName: DruidStatViewServlet
 * @author 16437
 * @date 2018年6月5日 20:58:22
 */
@WebServlet(urlPatterns = "/druid/*", initParams={
        @WebInitParam(name="allow",value=""),// IP白名单 (没有配置或者为空，则允许所有访问)
        @WebInitParam(name="deny",value="192.168.16.111"),// IP黑名单 (存在共同时，deny优先于allow)
        @WebInitParam(name="loginUsername",value="admin"),// 用户名
        @WebInitParam(name="loginPassword",value="admin"),// 密码
        @WebInitParam(name="resetEnable",value="true")// 禁用HTML页面上的“Reset All”功能
})
public class DruidStatViewServlet extends StatViewServlet {

}

5.扫描Servlet

注意要启动类中加上@ServletComponentScan注解，否则Servlet无法生效 。

package com.example.durid;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.ServletComponentScan;

@SpringBootApplication
@ServletComponentScan
public class DuridApplication {

	public static void main(String[] args) {
		SpringApplication.run(DuridApplication.class, args);
	}
}

6.手动初始化DataSource

有些版本存在自动初始化数据，SQL监控显示不出任何的内容问题，如果版本不存在bug可以跳过这一步。

package com.example.durid;

import com.alibaba.druid.pool.DruidDataSource;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;

import java.sql.SQLException;

@Configuration
public class DruidConfiguration {
    @Value("${spring.datasource.url}")
    private String dbUrl;
    @Value("${spring.datasource.username}")
    private String username;
    @Value("${spring.datasource.password}")
    private String password;
    @Value("${spring.datasource.driverClassName}")
    private String driverClassName;
    @Value("${spring.datasource.initialSize}")
    private int initialSize;
    @Value("${spring.datasource.minIdle}")
    private int minIdle;
    @Value("${spring.datasource.maxActive}")
    private int maxActive;
    @Value("${spring.datasource.maxWait}")
    private int maxWait;
    @Value("${spring.datasource.timeBetweenEvictionRunsMillis}")
    private int timeBetweenEvictionRunsMillis;
    @Value("${spring.datasource.minEvictableIdleTimeMillis}")
    private int minEvictableIdleTimeMillis;
    @Value("${spring.datasource.validationQuery}")
    private String validationQuery;
    @Value("${spring.datasource.testWhileIdle}")
    private boolean testWhileIdle;
    @Value("${spring.datasource.testOnBorrow}")
    private boolean testOnBorrow;
    @Value("${spring.datasource.testOnReturn}")
    private boolean testOnReturn;
    @Value("${spring.datasource.poolPreparedStatements}")
    private boolean poolPreparedStatements;
    @Value("${spring.datasource.maxPoolPreparedStatementPerConnectionSize}")
    private int maxPoolPreparedStatementPerConnectionSize;
    @Value("${spring.datasource.filters}")
    private String filters;
    @Value("${spring.datasource.connectionProperties}")
    private String connectionProperties;
    @Value("${spring.datasource.useGlobalDataSourceStat}")
    private boolean useGlobalDataSourceStat;

    @Bean     //声明其为Bean实例
    @Primary  //在同样的DataSource中，首先使用被标注的DataSource
    public DruidDataSource dataSource(){
        DruidDataSource datasource = new DruidDataSource();
        datasource.setUrl(this.dbUrl);
        datasource.setUsername(username);
        datasource.setPassword(password);
        datasource.setDriverClassName(driverClassName);

        //configuration
        datasource.setInitialSize(initialSize);
        datasource.setMinIdle(minIdle);
        datasource.setMaxActive(maxActive);
        datasource.setMaxWait(maxWait);
        datasource.setTimeBetweenEvictionRunsMillis(timeBetweenEvictionRunsMillis);
        datasource.setMinEvictableIdleTimeMillis(minEvictableIdleTimeMillis);
        datasource.setValidationQuery(validationQuery);
        datasource.setTestWhileIdle(testWhileIdle);
        datasource.setTestOnBorrow(testOnBorrow);
        datasource.setTestOnReturn(testOnReturn);
        datasource.setPoolPreparedStatements(poolPreparedStatements);
        datasource.setMaxPoolPreparedStatementPerConnectionSize(maxPoolPreparedStatementPerConnectionSize);
        datasource.setUseGlobalDataSourceStat(useGlobalDataSourceStat);
        try {
            datasource.setFilters(filters);
        } catch (SQLException e) {
            System.err.println("druid configuration initialization filter: "+ e);
        }
        datasource.setConnectionProperties(connectionProperties);
        return datasource;
    }

}

7.启动应用程序

在浏览器中输入http://localhost:8080/druid/login.html登陆

这样就已经配置好了。

参考：https://github.com/alibaba/druid