SpringBoot集成Druid

2024-01-02 17:16:58

Druid

是一个阿里开源的连接池组件
加⼊了日志监控，不需要额外的界面开发

详细介绍可以看官方文档：https://www.alibabacloud.com/help/zh/doc-detail/72987.htm

在springboot 2.0 以上默认都是使⽤用Hikari数据源， Hikari与Druid都是当前⽐比较优秀的数据源

com.alibaba.druid.pool.DruidDataSource 基本配置参数如下：

配置	缺省值	说明
name		配置这个属性的意义在于，如果存在多个数据源，监控的时候可以通过名字来区分开来。如果没有配置，将会生成一个名字，格式是：“DataSource-” + System.identityHashCode(this)
jdbcUrl		连接数据库的url，不同数据库不一样。例如： mysql : jdbc:mysql://10.20.153.104:3306/druid2 oracle : jdbc:oracle:thin:@10.20.149.85:1521:ocnauto
username		连接数据库的用户名
password		连接数据库的密码。如果你不希望密码直接写在配置文件中，可以使用ConfigFilter。详细看这里：https://github.com/alibaba/druid/wiki/%E4%BD%BF%E7%94%A8ConfigFilter
driverClassName		根据url自动识别这一项可配可不配，如果不配置druid会根据url自动识别dbType，然后选择相应的driverClassName(建议配置下)
initialSize	0	初始化时建立物理连接的个数。初始化发生在显示调用init方法，或者第一次getConnection时
maxActive	8	最大连接池数量
maxIdle	8	已经不再使用，配置了也没效果
minIdle		最小连接池数量
maxWait		获取连接时最大等待时间，单位毫秒。配置了maxWait之后，缺省启用公平锁，并发效率会有所下降，如果需要可以通过配置useUnfairLock属性为true使用非公平锁。
poolPreparedStatements	false	是否缓存preparedStatement，也就是PSCache。PSCache对支持游标的数据库性能提升巨大，比如说oracle。在mysql下建议关闭。
maxOpenPreparedStatements	-1	要启用PSCache，必须配置大于0，当大于0时，poolPreparedStatements自动触发修改为true。在Druid中，不会存在Oracle下PSCache占用内存过多的问题，可以把这个数值配置大一些，比如说100
validationQuery		用来检测连接是否有效的sql，要求是一个查询语句。如果validationQuery为null，testOnBorrow、testOnReturn、testWhileIdle都不会其作用。
testOnBorrow	true	申请连接时执行validationQuery检测连接是否有效，做了这个配置会降低性能。
validationQueryTimeout		单位：秒，检测连接是否有效的超时时间。底层调⽤用jdbc Statement对象的void setQueryTimeout(int seconds)⽅方法
testOnReturn	false	归还连接时执行validationQuery检测连接是否有效，做了这个配置会降低性能
testWhileIdle	false	建议配置为true，不影响性能，并且保证安全性。申请连接的时候检测，如果空闲时间大于timeBetweenEvictionRunsMillis，执行validationQuery检测连接是否有效。
timeBetweenEvictionRunsMillis	1分钟（1.0.14）	有两个含义： 1) Destroy线程会检测连接的间隔时间2) testWhileIdle的判断依据，详细看testWhileIdle属性的说明
numTestsPerEvictionRun		不再使用，一个DruidDataSource只支持一个EvictionRun
minEvictableIdleTimeMillis	30分钟（1.0.14）	连接保持空闲⽽而不不被驱逐的最⻓长时间
connectionInitSqls		物理连接初始化的时候执行的sql
exceptionSorter	根据dbType自动识别	当数据库抛出一些不可恢复的异常时，抛弃连接
filters		属性类型是字符串，通过别名的方式配置扩展插件，常用的插件有：监控统计用的filter:stat日志用的filter:log4j防御sql注入的filter:wall
proxyFilters		类型是List<com.alibaba.druid.filter.
maxPoolPreparedStatementPerConnectionSize	10	要启⽤用PSCache，必须配置⼤大于0，当⼤大于0时poolPreparedStatements自动触发修改为true。单个connnection独享⼀一个statement cache，也就是说maxOpenPreparedStatements是针对单个connection链接的

连接池运行原理

连接池初始化的时候按照initialSize创建多个连接
有DB操作访问的时候，就从里面取一个
如果当前正在使用的连接=maxActive,就会进入等待，没有到maxActive拿一个空闲连接，没有空闲就创建一个新连接，等待超过maxWati则会报错
使用完毕还回去等待其它人用，不会物理销毁
每一个connection在连接池里都有空闲时长的，允许最大空闲时长：minEvictableldleTimeMillis,多久检测一次：timeBetweenEvictionRunsMillis
maxActive如何配置：理论上应该设置成最大并发数
只要连接被前端业务拿到就算不空闲了，这个时候如果说长时间占有连接，连接数是不会崩溃，连接池主动关闭是使用中的连接，属于一个高级功能
removeAbandoned=“true”
removeAbandonedTimeout=“60”
logAbandoned=“true”

知道了连接池的运行原理之后，我们就正式来用SpringBoot来集成它吧

导入依赖：

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid-spring-boot-starter</artifactId>
    <version>1.1.21</version>
</dependency>

编写配置文件：application.yaml

 spring:
datasource:
  username: root
  password: 123456
  url: jdbc:mysql://localhost:3306/ec_admin?useUnicode=true&characterEncoding=UTF-8
  driver-class-name: com.mysql.jdbc.Driver
  type: com.alibaba.druid.pool.DruidDataSource
  #Spring Boot 默认是不注入这些属性值的，需要自己绑定
  #druid 数据源专有配置
  initialSize: 5
  minIdle: 5
  maxActive: 20
  maxWait: 60000
  timeBetweenEvictionRunsMillis: 60000
  minEvictableIdleTimeMillis: 300000
  validationQuery: SELECT 1 FROM DUAL
  testWhileIdle: true
  testOnBorrow: false
  testOnReturn: false
  # 打开PSCache
  poolPreparedStatements: true
  #配置监控统计拦截的filters，stat:监控统计、log4j：日志记录、wall：防御sql注入
  #如果运行时报错  java.lang.ClassNotFoundException: org.apache.log4j.Priority
  #则导入 log4j 依赖即可，Maven 地址： https://mvnrepository.com/artifact/log4j/log4j
  filters: stat,wall,log4j,config
  #指定每个连接上PSCache的大小
  maxPoolPreparedStatementPerConnectionSize: 20
  #合并多个DruidDataSource的监控数据
  useGlobalDataSourceStat: true
  #通过connectProperties属性来打开mergeSql功能；慢SQL记录
  connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000

3、编写配置类：

@Configuration
public class DruidConfig {
<span class="token annotation punctuation">@ConfigurationProperties</span><span class="token punctuation">(</span>prefix <span class="token operator">=</span> <span class="token string">"spring.datasource"</span><span class="token punctuation">)</span>
<span class="token annotation punctuation">@Bean</span>
<span class="token keyword">public</span> DataSource <span class="token function">druidDataSource</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">{<!-- --></span>
    <span class="token keyword">return</span> <span class="token keyword">new</span> <span class="token class-name">DruidDataSource</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token punctuation">}</span>
<span class="token comment">//因为Springboot内置了servlet容器，所以没有web.xml，替代方法就是将ServletRegistrationBean注册进去</span>
<span class="token comment">//加入后台监控</span>
<span class="token annotation punctuation">@Bean</span>  <span class="token comment">//这里其实就相当于servlet的web.xml</span>
<span class="token keyword">public</span> ServletRegistrationBean <span class="token function">statViewServlet</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">{<!-- --></span>
    ServletRegistrationBean<span class="token generics function"><span class="token punctuation">&lt;</span>StatViewServlet<span class="token punctuation">&gt;</span></span> bean <span class="token operator">=</span>
            <span class="token keyword">new</span> <span class="token class-name">ServletRegistrationBean</span><span class="token generics function"><span class="token punctuation">&lt;</span>StatViewServlet<span class="token punctuation">&gt;</span></span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">StatViewServlet</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span><span class="token string">"/druid/*"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

    <span class="token comment">//后台需要有人登录，进行配置</span>
    <span class="token operator">/</span><span class="token operator">/</span>bean<span class="token punctuation">.</span><span class="token function">addUrlMappings</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> 这个可以添加映射，我们在构造里已经写了
    <span class="token operator">/</span><span class="token operator">/</span>设置一些初始化参数
    Map<span class="token generics function"><span class="token punctuation">&lt;</span>String<span class="token punctuation">,</span>String<span class="token punctuation">&gt;</span></span> initParas <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">HashMap</span><span class="token generics function"><span class="token punctuation">&lt;</span>String<span class="token punctuation">,</span>String<span class="token punctuation">&gt;</span></span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    initParas<span class="token punctuation">.</span><span class="token function">put</span><span class="token punctuation">(</span><span class="token string">"loginUsername"</span><span class="token punctuation">,</span><span class="token string">"admin"</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token operator">/</span><span class="token operator">/</span>它这个账户密码是固定的
    initParas<span class="token punctuation">.</span><span class="token function">put</span><span class="token punctuation">(</span><span class="token string">"loginPassword"</span><span class="token punctuation">,</span><span class="token string">"123456"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token operator">/</span><span class="token operator">/</span>允许谁能防伪
    initParas<span class="token punctuation">.</span><span class="token function">put</span><span class="token punctuation">(</span><span class="token string">"allow"</span><span class="token punctuation">,</span><span class="token string">""</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token operator">/</span><span class="token operator">/</span>这个值为空或没有就允许所有人访问，ip白名单
    <span class="token operator">/</span><span class="token operator">/</span>initParas<span class="token punctuation">.</span><span class="token function">put</span><span class="token punctuation">(</span><span class="token string">"allow"</span><span class="token punctuation">,</span><span class="token string">"localhost"</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token operator">/</span><span class="token operator">/</span>只允许本机访问，多个ip用逗号<span class="token punctuation">,</span>隔开
    <span class="token operator">/</span><span class="token operator">/</span>initParas<span class="token punctuation">.</span><span class="token function">put</span><span class="token punctuation">(</span><span class="token string">"deny"</span><span class="token punctuation">,</span><span class="token string">""</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token operator">/</span><span class="token operator">/</span>ip黑名单，拒绝谁访问 deny和allow同时存在优先deny
    initParas<span class="token punctuation">.</span><span class="token function">put</span><span class="token punctuation">(</span><span class="token string">"resetEnable"</span><span class="token punctuation">,</span><span class="token string">"false"</span><span class="token punctuation">)</span><span class="token punctuation">;</span><span class="token operator">/</span><span class="token operator">/</span>禁用HTML页面的Reset按钮
    bean<span class="token punctuation">.</span><span class="token function">setInitParameters</span><span class="token punctuation">(</span>initParas<span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token keyword">return</span> bean<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

<span class="token operator">/</span><span class="token operator">/</span>再配置一个过滤器，Servlet按上面的方式注册Filter也只能这样
<span class="token annotation punctuation">@Bean</span>
<span class="token keyword">public</span> FilterRegistrationBean <span class="token function">webStatFilter</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">{<!-- --></span>
    FilterRegistrationBean bean <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">FilterRegistrationBean</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token operator">/</span><span class="token operator">/</span>可以设置也可以获取<span class="token punctuation">,</span>设置一个阿里巴巴的过滤器
    bean<span class="token punctuation">.</span><span class="token function">setFilter</span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">WebStatFilter</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    bean<span class="token punctuation">.</span><span class="token function">addUrlPatterns</span><span class="token punctuation">(</span><span class="token string">"/*"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token comment">//可以过滤和排除哪些东西</span>
    Map<span class="token generics function"><span class="token punctuation">&lt;</span>String<span class="token punctuation">,</span>String<span class="token punctuation">&gt;</span></span> initParams <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">HashMap</span><span class="token generics function"><span class="token punctuation">&lt;</span>String<span class="token punctuation">,</span>String<span class="token punctuation">&gt;</span></span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token operator">/</span><span class="token operator">/</span>把不需要监控的过滤掉<span class="token punctuation">,</span>这些不进行统计
    initParams<span class="token punctuation">.</span><span class="token function">put</span><span class="token punctuation">(</span><span class="token string">"exclusions"</span><span class="token punctuation">,</span><span class="token string">"*.js,*.css,/druid/*"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    bean<span class="token punctuation">.</span><span class="token function">setInitParameters</span><span class="token punctuation">(</span>initParams<span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token keyword">return</span> bean<span class="token punctuation">;</span>
<span class="token punctuation">}</span>

编写完之后我们启动项目，访问http://localhost:8080/druid/login.html
就会到Druid的监控登录界面

输入我们配置的登录用户名和密码进行登录即可访问

使用这个我们可以很好的监控我们的数据库了

这里要注意一个参数：PSCache

PSCache

PreparedStatement Cache
就要从MySQL的SQL执⾏行行过程来讲
连接器器
- 进⾏行行数据库连接，⽤用户名密码验证
- show processlist
查询缓存
- key-value， key是SQL， value就是结果集
- ⼤大多数情况下不不建议使⽤用查询缓存
  - testOnBorrow: false
  - testOnReturn: false
  - poolPreparedStatements: false
- query_cache_type : DEMAND //默认的SQL都不不使⽤用查询缓存
- mysql> select SQL_CACHE * from student where id=1; //声明使⽤用
分析器器
- 词法分析
  - SQL的关键词进⾏行行识别
- 语法分析
  - 对语法进⾏行行分析 “use near”
优化器器
- 决定我们SQL使⽤用那个⼈人索引
执⾏器
- 会判断你是否对这个表有查询/更更新权限
存储引擎
- 获取数据的具体⽂文件地址

SQL的写法
select * from userinfo where id=? //PreparedStatement id=1 id=2 硬解析1次
select * from userinfo where id=1 / select * from user info id=2（这个在数据库都认为是两个不不同的SQL）硬解析2次

词法、语法、语义、优化器器（执⾏计划）、执⾏
硬解析：词法、语法
结论： prepare语法适⽤用于执⾏行行频繁且复杂的SQL
prepare+execute两次

数据库密码加密
执行以下命令，会生成加密的密码和private key,public key

java -cp /Users/gavin/Documents/maven-repo/com/alibaba/druid/1.1.21/druid-
1.1.21.jar com.alibaba.druid.filter.config.ConfigTools 你的密码

生成的public key：

druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000;config.decrypt=true;con
fig.decrypt.key=MFwwDQYJKoZIhvcNAQEBBQADSwAwSAJBAM9l5I7/YAFtLPr2Ep1G70ovzMX8Ncd9jcuKUWaWEiJ/3SLu90v/K0IPxqYGDYaI+QmulYgecmyQ+XJIdpimtqsCAwEAAQ==

#通过connectProperties属性来打开mergeSql功能；慢SQL记录，这⾥里里⽅方publickey
connectionProperties:
druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000;config.decrypt=true;con
fig.decrypt.key=MFwwDQYJKoZIhvcNAQEBBQADSwAwSAJBAM9l5I7/YAFtLPr2Ep1G70ovzMX8Nc
d9jcuKUWaWEiJ/3SLu90v/K0IPxqYGDYaI+QmulYgecmyQ+XJIdpimtqsCAwEAAQ

使用spring框架配置，可以参考这篇文章：https://www.cnblogs.com/wuyun-blog/p/5679073.html

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