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SpringBoot之数据库连接池(druid)

2016-12-14 18:09 239 查看


1.介绍

SpringBoot默认使用 org.apache.tomcat.jdbc.pool.DataSource

Tomcat 在 7.0 以前的版本都是使用 commons-dbcp 做为连接池的实现,但是 dbcp 饱受诟病,原因有:

dbcp 是单线程的,为了保证线程安全会锁整个连接池
dbcp 性能不佳
dbcp 太复杂,超过 60 个类
dbcp 使用静态接口,在 JDK 1.6 编译有问题
dbcp 发展滞后

因此很多人会选择一些第三方的连接池组件,例如 c3p0 , bonecp, druid (@wenshao )
等。

为此,Tomcat 从 7.0 开始引入一个新的模块:Tomcat jdbc pool

tomcat jdbc pool 近乎兼容 dbcp ,性能更高
异步方式获取连接
tomcat jdbc pool 是 tomcat 的一个模块,基于 tomcat JULI,使用 Tomcat 的日志框架
使用 javax.sql.PooledConnection 接口获取连接
支持高并发应用环境
超简单,核心文件只有8个,比 c3p0 还
更好的空闲连接处理机制
支持 JMX
支持 XA Connection

tomcat jdbc pool 的优点远不止这些,详情请看这里

tomcat jdbc pool 可在 Tomcat 中直接使用,也可以在独立的应用中使用。

Tomcat 中直接使用的方法:

数据源配置:

01
<
Resource
name
=
"jdbc/TestDB"
02
auth
=
"Container"
03
type
=
"javax.sql.DataSource"
04
factory
=
"org.apache.tomcat.jdbc.pool.DataSourceFactory"
05
testWhileIdle
=
"true"
06
testOnBorrow
=
"true"
07
testOnReturn
=
"false"
08
validationQuery
=
"SELECT
1"
09
validationInterval
=
"30000"
10
timeBetweenEvictionRunsMillis
=
"30000"
11
maxActive
=
"100"
12
minIdle
=
"10"
13
maxWait
=
"10000"
14
initialSize
=
"10"
15
removeAbandonedTimeout
=
"60"
16
removeAbandoned
=
"true"
17
logAbandoned
=
"true"
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minEvictableIdleTimeMillis
=
"30000"
19
jmxEnabled
=
"true"
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jdbcInterceptors
=
21
"org.apache.tomcat.jdbc.pool.interceptor.ConnectionState;org.apache.tomcat.jdbc.pool.interceptor.StatementFinalizer"
22
username
=
"root"
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password
=
"password"
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driverClassName
=
"com.mysql.jdbc.Driver"
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url
=
"jdbc:mysql://localhost:3306/mysql"
/>
异步获取连接的方法:

01
Connection
con =
null
;
02
try
{
03
Future<Connection>
future = datasource.getConnectionAsync();
04
while
(!future.isDone())
{
05
System.out.println(
"Connection
is not yet available. Do some background work"
);
06
try
{
07
Thread.sleep(
100
);
//simulate
work
08
}
catch
(InterruptedException
x){
09
Thread.currentThread().interrupted();
10
}
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}
12
con
= future.get();
//should
return instantly
13
Statement
st = con.createStatement();
14
ResultSet
rs = st.executeQuery(
"select
* from user"
);
在独立的应用中使用:

01
import
java.sql.Connection;
02
import
java.sql.ResultSet;
03
import
java.sql.Statement;
04
05
import
org.apache.tomcat.jdbc.pool.DataSource;
06
import
org.apache.tomcat.jdbc.pool.PoolProperties;
07
08
public
class
SimplePOJOExample
{
09
10
public
static
void
main(String[]
args)
throws
Exception
{
11
PoolProperties
p =
new
PoolProperties();
12
p.setUrl(
"jdbc:mysql://localhost:3306/mysql"
);
13
p.setDriverClassName(
"com.mysql.jdbc.Driver"
);
14
p.setUsername(
"root"
);
15
p.setPassword(
"password"
);
16
p.setJmxEnabled(
true
);
17
p.setTestWhileIdle(
false
);
18
p.setTestOnBorrow(
true
);
19
p.setValidationQuery(
"SELECT
1"
);
20
p.setTestOnReturn(
false
);
21
p.setValidationInterval(
30000
);
22
p.setTimeBetweenEvictionRunsMillis(
30000
);
23
p.setMaxActive(
100
);
24
p.setInitialSize(
10
);
25
p.setMaxWait(
10000
);
26
p.setRemoveAbandonedTimeout(
60
);
27
p.setMinEvictableIdleTimeMillis(
30000
);
28
p.setMinIdle(
10
);
29
p.setLogAbandoned(
true
);
30
p.setRemoveAbandoned(
true
);
31
p.setJdbcInterceptors(
"org.apache.tomcat.jdbc.pool.interceptor.ConnectionState;"
+
32
"org.apache.tomcat.jdbc.pool.interceptor.StatementFinalizer"
);
33
DataSource
datasource =
new
DataSource();
34
datasource.setPoolProperties(p);
35
36
Connection
con =
null
;
37
try
{
38
con
= datasource.getConnection();
39
Statement
st = con.createStatement();
40
ResultSet
rs = st.executeQuery(
"select
* from user"
);
41
int
cnt
=
1
;
42
while
(rs.next())
{
43
System.out.println((cnt++)+
".
Host:"
+rs.getString(
"Host"
)+
44
"
User:"
+rs.getString(
"User"
)+
"
Password:"
+rs.getString(
"Password"
));
45
}
46
rs.close();
47
st.close();
48
}
finally
{
49
if
(con!=
null
)
try
{con.close();}
catch
(Exception
ignore){}
50
}
51
}
52
53
}
以上只是简单的介绍,具体的使用方法还需参考:

https://tomcat.apache.org/tomcat-7.0-doc/jdbc-pool.html



Druid是一个JDBC组件库,包括数据库连接池、SQL Parser等组件。DruidDataSource是最好的数据库连接池。SpringBoot支持任何一种数据库链接池的配置,在这里用druid作为例子进行讲解


2.快速开始

这块先以spring的JdbcTemplate为列子进行讲解


pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.4.1.RELEASE</version>
</parent>
<modelVersion>4.0.0</modelVersion>

<artifactId>springboot-6</artifactId>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
<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>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.39</version>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.0.26</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<version>1.4.1.RELEASE</version>
<configuration>
<fork>true</fork>
</configuration>
</plugin>
</plugins>
</build>

</project>
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[/code]

配置统一的DataSource,这种方式不太合适生产环境,SpringBoot可以统一的配置application.yaml,但是目前仅仅支持dbcp、dbcp2、hikari

下面这种方式无法不支持的DruidDataSource的其他参数


application.yaml

spring:
datasource:
driver-class-name: com.mysql.jdbc.Driver
username: root
password: qq123456
url: jdbc:mysql://localhost:3306/test1
type: com.alibaba.druid.pool.DruidDataSource
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[/code]


通过代码的方式进行配置


@SpringBootApplication
public class AppApplication {

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

/**
* 注册DruidServlet
*
* @return
*/
@Bean
public ServletRegistrationBean druidServletRegistrationBean(){
ServletRegistrationBean servletRegistrationBean = new ServletRegistrationBean();
servletRegistrationBean.setServlet(new StatViewServlet());
servletRegistrationBean.addUrlMappings("/druid/*");
return servletRegistrationBean;
}

/**
* 注册DruidFilter拦截
*
* @return
*/
@Bean
public FilterRegistrationBean duridFilterRegistrationBean(){
FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean();
filterRegistrationBean.setFilter(new WebStatFilter());
Map<String, String> initParams = new HashMap<String, String>();
//设置忽略请求
initParams.put("exclusions", "*.js,*.gif,*.jpg,*.bmp,*.png,*.css,*.ico,/druid/*");
filterRegistrationBean.setInitParameters(initParams);
filterRegistrationBean.addUrlPatterns("/*");
return filterRegistrationBean;
}

/**
* 配置DataSource
* @return
* @throws SQLException
*/
@Bean
public DataSource druidDataSource()throws SQLException {
DruidDataSource druidDataSource = new DruidDataSource();
druidDataSource.setUsername("root");
druidDataSource.setPassword("qq123456");
druidDataSource.setUrl("jdbc:mysql://localhost:3306/test1");
druidDataSource.setMaxActive(100);
druidDataSource.setFilters("stat,wall");
druidDataSource.setInitialSize(10);
return druidDataSource;
}

}

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[/code]

这块采用的是
ServletRegistrationBean
FilterRegistrationBean
的方式进行注册Servlet和Filter,这种是SpingBoot里面提供支持原生的方式

除了这种方式还可以采用其他方式进行配置,采用Servlet3.0的注解Servlet进行配置

这块配置基本就完事了,可以访问本地链接http://localhost:8080/druid/datasource.html查看监控信息


官方资料

其他的详细配置可以查看官方文档进行配置,这里不过多讲述

https://github.com/alibaba/druid/wiki/%E9%A6%96%E9%A1%B5
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