前言
本章节主要讲解Druid数据库连接池,为什么要学Druid数据库连接池呢??
我的知识储备数据库连接池有两种->C3P0,DBCP,可是现在看起来并不够用阿~当时学习C3P0的时候,觉得这个数据库连接池是挺强大的。看过的一些书上也是多数介绍了这两种数据库连接池,自己做的Demo也是使用C3P0。可是现在看起来这两种都不够了~业界发展得真快呀


上面的我就没有打码了,都是一些热心的开发者评论,正因为他们的评论才促使我会去学更好的东西,也希望大家多多指点~
于是乎,我就花一点时间去学习Druid数据库连接池了…如果有错的地方往指正~~
Druid数据库连接池是阿里的,因此文档是有中文版本的,英语不好学起来也不用那么头疼.
一、Druid介绍
Druid一般的用处有两个:
所以本文主要是使用Druid作为数据库连接池并且使用一下实时监控应用,做个入门学习~
二、搭建Druid环境
由于简化配置,我就直接实用SpringBoot和SpringData JPA的方式来搭建一个Druid的Demo了~~~
2.1引入pom
<dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> </dependency> <dependency> <groupId>com.alibaba</groupId> <artifactId>druid</artifactId> <version>1.1.5</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-jpa</artifactId> </dependency> <dependency> <groupId>ch.qos.logback</groupId> <artifactId>logback-classic</artifactId> <version>1.2.3</version> <scope>test</scope> </dependency></dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.1.5</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-classic</artifactId>
<version>1.2.3</version>
<scope>test</scope>
</dependency>
</dependencies>
2.2Druid默认的配置
配置数据源的信息(Druid),和JPA相关配置~
# 数据库访问配置# 主数据源,默认的spring.datasource.type=com.alibaba.druid.pool.DruidDataSourcespring.datasource.driver-class-name=com.mysql.jdbc.Driverspring.datasource.url=jdbc:mysql://localhost:3306/druidspring.datasource.username=rootspring.datasource.password=root# 下面为连接池的补充设置,应用到上面所有数据源中# 初始化大小,最小,最大spring.datasource.initialSize=5spring.datasource.minIdle=5spring.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=300000spring.datasource.validationQuery=SELECT 1 FROM DUALspring.datasource.testWhileIdle=truespring.datasource.testOnBorrow=falsespring.datasource.testOnReturn=false# 打开PSCache,并且指定每个连接上PSCache的大小spring.datasource.poolPreparedStatements=truespring.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#JPA配置spring.jpa.hibernate.ddl-auto=updatespring.jpa.show-sql=truespring.jackson.serialization.indent_output=true
spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/druid
spring.datasource.username=root
spring.datasource.password=root
# 下面为连接池的补充设置,应用到上面所有数据源中
# 初始化大小,最小,最大
spring.datasource.initialSize=5
spring.datasource.minIdle=5
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
spring.datasource.validationQuery=SELECT 1 FROM DUAL
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
#JPA配置
spring.jpa.hibernate.ddl-auto=update
spring.jpa.show-sql=true
spring.jackson.serialization.indent_output=true
更多的配置要去看官方文档了~不过这里一般就够用了。
2.3配置监控页面
Druid的监控统计功能是通过filter-chain扩展实现,如果你要打开监控统计功能,配置StatFilter
配置druid数据源状态监控,配置一个拦截器和一个Servlet即可~
package com.example.demo;/** * Created by ozc on 2018/3/26. * * @author ozc * @version 1.0 */import com.alibaba.druid.support.http.StatViewServlet;import com.alibaba.druid.support.http.WebStatFilter;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;/** * druid 配置. * <p> * 这样的方式不需要添加注解:@ServletComponentScan * * @author Administrator */@Configurationpublic class DruidConfiguration { /** * 注册一个StatViewServlet * * @return */ @Bean public ServletRegistrationBean DruidStatViewServle2() { //org.springframework.boot.context.embedded.ServletRegistrationBean提供类的进行注册. ServletRegistrationBean servletRegistrationBean = new ServletRegistrationBean(new StatViewServlet(), "/druid/*"); //添加初始化参数:initParams //白名单: servletRegistrationBean.addInitParameter("allow", "127.0.0.1"); //IP黑名单 (存在共同时,deny优先于allow) : 如果满足deny的话提示:Sorry, you are not permitted to view this page. servletRegistrationBean.addInitParameter("deny", "192.168.1.73"); //登录查看信息的账号密码. servletRegistrationBean.addInitParameter("loginUsername", "admin2"); servletRegistrationBean.addInitParameter("loginPassword", "123456"); //是否能够重置数据. servletRegistrationBean.addInitParameter("resetEnable", "false"); return servletRegistrationBean; } /** * 注册一个:filterRegistrationBean * * @return */ @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; }}
/**
* Created by ozc on 2018/3/26.
*
* @author ozc
* @version 1.0
*/
import com.alibaba.druid.support.http.StatViewServlet;
import com.alibaba.druid.support.http.WebStatFilter;
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;
/**
* druid 配置.
* <p>
* 这样的方式不需要添加注解:@ServletComponentScan
*
* @author Administrator
*/
@Configuration
public class DruidConfiguration {
/**
* 注册一个StatViewServlet
*
* @return
*/
@Bean
public ServletRegistrationBean DruidStatViewServle2() {
//org.springframework.boot.context.embedded.ServletRegistrationBean提供类的进行注册.
ServletRegistrationBean servletRegistrationBean = new ServletRegistrationBean(new StatViewServlet(), "/druid/*");
//添加初始化参数:initParams
//白名单:
servletRegistrationBean.addInitParameter("allow", "127.0.0.1");
//IP黑名单 (存在共同时,deny优先于allow) : 如果满足deny的话提示:Sorry, you are not permitted to view this page.
servletRegistrationBean.addInitParameter("deny", "192.168.1.73");
//登录查看信息的账号密码.
servletRegistrationBean.addInitParameter("loginUsername", "admin2");
servletRegistrationBean.addInitParameter("loginPassword", "123456");
//是否能够重置数据.
servletRegistrationBean.addInitParameter("resetEnable", "false");
return servletRegistrationBean;
}
/**
* 注册一个:filterRegistrationBean
*
* @return
*/
@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;
}
}

2.4JPA测试
POJO:
@Entitypublic class User implements Serializable { /** * serialVersionUID. */ private static final long serialVersionUID = 1L; /** * 主键. */ @Id @GeneratedValue private String id; /** * 用户名. */ private String userName = ""; /** * 手机号码. */ private String mobileNo = ""; /** * 邮箱. */ private String email = ""; /** * 密码. */ private String password = ""; /** * 用户类型. */ private Integer userType = 0; /** * 注册时间. */ private Date registerTime = new Date(); /** * 所在区域. */ private String region = ""; /** * 是否有效 0 有效 1 无效. */ private Integer validity = 0; /** * 头像. */ private String headPortrait = "";}
public class User implements Serializable {
/**
* serialVersionUID.
*/
private static final long serialVersionUID = 1L;
/**
* 主键.
*/
@Id
@GeneratedValue
private String id;
/**
* 用户名.
*/
private String userName = "";
/**
* 手机号码.
*/
private String mobileNo = "";
/**
* 邮箱.
*/
private String email = "";
/**
* 密码.
*/
private String password = "";
/**
* 用户类型.
*/
private Integer userType = 0;
/**
* 注册时间.
*/
private Date registerTime = new Date();
/**
* 所在区域.
*/
private String region = "";
/**
* 是否有效 0 有效 1 无效.
*/
private Integer validity = 0;
/**
* 头像.
*/
private String headPortrait = "";
}
Controller:
@RestControllerpublic class UserController { @Autowired private UserRepos userRepos; @RequestMapping(value="saveUser") public User saveUser(){ return userRepos.save(new User()); } @RequestMapping(value="/findByUserName") public List<User> findByUserName(String userName){ return userRepos.findByUserName(userName); } @RequestMapping(value="findByUserNameLike") public List<User> findByUserNameLkie(String userName){ return userRepos.findByUserNameLike(userName); } @RequestMapping(value="findByPage") public Page<User> findByPage(Integer userType){ return userRepos.findByUserType(userType, new PageRequest(1, 5)); }}
public class UserController {
@Autowired
private UserRepos userRepos;
@RequestMapping(value="saveUser")
public User saveUser(){
return userRepos.save(new User());
}
@RequestMapping(value="/findByUserName")
public List<User> findByUserName(String userName){
return userRepos.findByUserName(userName);
}
@RequestMapping(value="findByUserNameLike")
public List<User> findByUserNameLkie(String userName){
return userRepos.findByUserNameLike(userName);
}
@RequestMapping(value="findByPage")
public Page<User> findByPage(Integer userType){
return userRepos.findByUserType(userType, new PageRequest(1, 5));
}
}
Repository:
public interface UserRepos extends JpaRepository<User, String> { /** * 通过用户名相等查询 * * @param userName 用户名 * @return */ List<User> findByUserName(String userName); /** * 通过名字like查询 * * @param userName 用户名 * @return */ List<User> findByUserNameLike(String userName); /** * 通过用户名和手机号码查询 * * @param userName 用户名 * @param mobileNo 手机号码 * @return */ User findByUserNameAndMobileNo(String userName, String mobileNo); /** * 根据用户类型,分页查询 * * @param userType 用户类型 * @param pageable * @return */ Page<User> findByUserType(Integer userType, Pageable pageable); /** * 根据用户名,排序查询 * * @param userName 用户名 * @param sort * @return */ List<User> findByUserName(String userName, Sort sort);}interface UserRepos extends JpaRepository<User, String> {
/**
* 通过用户名相等查询
*
* @param userName 用户名
* @return
*/
List<User> findByUserName(String userName);
/**
* 通过名字like查询
*
* @param userName 用户名
* @return
*/
List<User> findByUserNameLike(String userName);
/**
* 通过用户名和手机号码查询
*
* @param userName 用户名
* @param mobileNo 手机号码
* @return
*/
User findByUserNameAndMobileNo(String userName, String mobileNo);
/**
* 根据用户类型,分页查询
*
* @param userType 用户类型
* @param pageable
* @return
*/
Page<User> findByUserType(Integer userType, Pageable pageable);
/**
* 根据用户名,排序查询
*
* @param userName 用户名
* @param sort
* @return
*/
List<User> findByUserName(String userName, Sort sort);
}
在页面上访问:http://localhost:8080/findByUserName?userName=Java3y
结果:


三、最后
本文只是简单的对Druid进行入门,Druid是一个非常好的开源数据库连接池框架,更多的资料可看GitHub的文档。
参考资料:
如果文章有错的地方欢迎指正,大家互相交流。习惯在微信看技术文章,想要获取更多的Java资源的同学,可以关注微信公众号:Java3y