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如何在SpringBoot 中使用 Druid 數(shù)據(jù)庫連接池

更新時(shí)間：2021年03月19日 17:14:00 作者：水貨程序員

這篇文章主要介紹了SpringBoot 中使用 Druid 數(shù)據(jù)庫連接池的實(shí)現(xiàn)步驟，幫助大家更好的理解和學(xué)習(xí)使用SpringBoot，感興趣的朋友可以了解下

1.Maven中的pom文件

<dependency>
	<groupId>com.alibaba</groupId>
	<artifactId>druid</artifactId>
	<version>1.1.14</version>
</dependency>
<dependency>
	<groupId>log4j</groupId>
	<artifactId>log4j</artifactId>
	<version>1.2.17</version>
</dependency>

使用 Spring Boot-2.x時(shí)，如果未引入log4j，在配置 Druid 時(shí)，會(huì)遇到Caused by: java.lang.ClassNotFoundException: org.apache.log4j.Priority的報(bào)錯(cuò)。因?yàn)镾pring Boot默認(rèn)使用的是log4j2。

2.SpringBoot 配置文件

下面是一個(gè)完整的yml文件的，其中使用mybatis作為數(shù)據(jù)庫訪問框架

server:
 servlet:
 context-path: /
 session:
  timeout: 60m
 port: 8080

spring:
 datasource:
 url: jdbc:mysql://127.0.0.1:9080/hospital?allowMultiQueries=true&useUnicode=true&characterEncoding=UTF-8&zeroDateTimeBehavior=convertToNull
 username: root
 password: root
 # 環(huán)境 dev|test|pro
 profiles:
  active: dev
 driver-class-name: com.mysql.cj.jdbc.Driver

 ########################## druid配置 ##########################
 type: com.alibaba.druid.pool.DruidDataSource
 # 初始化大小，最小，最大 
 initialSize: 5
 minIdle: 1
 maxActive: 20
  # 配置獲取連接等待超時(shí)的時(shí)間 
 maxWait: 60000
 # 配置間隔多久才進(jìn)行一次檢測，檢測需要關(guān)閉的空閑連接，單位是毫秒 
 timeBetweenEvictionRunsMillis: 60000
 # 配置一個(gè)連接在池中最小生存的時(shí)間，單位是毫秒 
 minEvictableIdleTimeMillis: 300000
 # 校驗(yàn)SQL，Oracle配置 validationQuery=SELECT 1 FROM DUAL，如果不配validationQuery項(xiàng)，則下面三項(xiàng)配置無用 
 validationQuery: SELECT 1 FROM DUAL
 testWhileIdle: true
 testOnBorrow: false
 testOnReturn: false
 # 打開PSCache，并且指定每個(gè)連接上PSCache的大小 
 poolPreparedStatements: true
 maxPoolPreparedStatementPerConnectionSize: 20
 # 配置監(jiān)控統(tǒng)計(jì)攔截的filters，去掉后監(jiān)控界面sql無法統(tǒng)計(jì)，'wall'用于防火墻 
 filters: stat,wall,log4j
 # 通過connectProperties屬性來打開mergeSql功能；慢SQL記錄 
 connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000
 # 合并多個(gè)DruidDataSource的監(jiān)控?cái)?shù)據(jù) 
 useGlobalDataSourceStat: true
 
# Mybatis配置
mybatis:
 mapperLocations: classpath:mapper/*.xml,classpath:mapper/extend/*.xml
 configuration:
 map-underscore-to-camel-case: true
 log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

3.配置Druid數(shù)據(jù)源實(shí)例

由于Druid暫時(shí)不在Spring Boot中的直接支持，故需要進(jìn)行配置信息的定制：

SpringBoot中的配置信息無法再Druid中直接生效，需要在Spring容器中實(shí)現(xiàn)一個(gè)DataSource實(shí)例。

import java.sql.SQLException;
import javax.sql.DataSource;
import org.apache.log4j.Logger;
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 com.alibaba.druid.pool.DruidDataSource;

@Configuration
public class DruidDBConfig {
	private Logger logger = Logger.getLogger(this.getClass());	//log4j日志

	@Value("${spring.datasource.url}")
	private String dbUrl;

	@Value("${spring.datasource.username}")
	private String username;

	@Value("${spring.datasource.password}")
	private String password;

	@Value("${spring.datasource.driver-class-name}")
	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;

	@Bean // 聲明其為Bean實(shí)例
	@Primary // 在同樣的DataSource中，首先使用被標(biāo)注的DataSource
	public DataSource dataSource() {
		DruidDataSource datasource = new DruidDataSource();

		datasource.setUrl(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);
		try {
			datasource.setFilters(filters);
		} catch (SQLException e) {
			//logger.error("druid configuration initialization filter", e);
			logger.error("druid configuration initialization filter", e);
			e.printStackTrace();
		}
		datasource.setConnectionProperties(connectionProperties);

		return datasource;
	}

}

4.過濾器和Servlet

還需要實(shí)現(xiàn)一個(gè)過濾器和Servlet，用于訪問統(tǒng)計(jì)頁面。

過濾器

import javax.servlet.annotation.WebFilter;
import javax.servlet.annotation.WebInitParam;
import com.alibaba.druid.support.http.WebStatFilter;
@WebFilter(filterName="druidWebStatFilter",urlPatterns="/*",
 initParams={
 @WebInitParam(name="exclusions",value="*.js,*.gif,*.jpg,*.bmp,*.png,*.css,*.ico,/druid/*")//忽略資源
 }
)
public class DruidStatFilter extends WebStatFilter {
 }

Servlet

import javax.servlet.annotation.WebInitParam;
import javax.servlet.annotation.WebServlet;
 
import com.alibaba.druid.support.http.StatViewServlet;
 
@WebServlet(urlPatterns="/druid/*",
 initParams={
   @WebInitParam(name="allow",value="127.0.0.1,192.168.163.1"),// IP白名單(沒有配置或者為空，則允許所有訪問)
   @WebInitParam(name="deny",value="192.168.1.73"),// IP黑名單 (存在共同時(shí)，deny優(yōu)先于allow)
   @WebInitParam(name="loginUsername",value="admin"),// 用戶名
   @WebInitParam(name="loginPassword",value="admin"),// 密碼
   @WebInitParam(name="resetEnable",value="false")// 禁用HTML頁面上的“Reset All”功能
})
public class DruidStatViewServlet extends StatViewServlet {
	private static final long serialVersionUID = -2688872071445249539L;
 
}

5.使用@ServletComponentScan注解，

使得剛才創(chuàng)建的Servlet，F(xiàn)ilter能被訪問，SpringBoot掃描并注冊。

@SpringBootApplication()
@MapperScan("cn.china.mytestproject.dao")
//添加servlet組件掃描，使得Spring能夠掃描到我們編寫的servlet和filter
@ServletComponentScan
public class MytestprojectApplication {
 public static void main(String[] args) {
 SpringApplication.run(MytestprojectApplication.class, args);
 } 
}