springboot的缓存技术的实现
引子
我门知道一个程序的瓶颈在于数据库,我门也知道内存的速度是大大快于硬盘的速度的。当我门需要重复的获取相同的数据的时候,我门一次又一次的请求数据库或者远程服务,导致大量的时间耗费在数据库查询或者远程方法的调用上,导致程序性能的恶化,这更是数据缓存要解决的问题。
spring 缓存支持
spring定义了 org.springframework.cache.cachemanager和org.springframework.cache.cache接口来统一不同的缓存技术。其中,cachemanager是spring提供的各种缓存技术抽象接口,cache接口包含了缓存的各种操作(增加、删除获得缓存,我门一般不会直接和此接口打交道)
spring 支持的cachemanager
针对不同的缓存技术,需要实现不同的cachemanager ,spring 定义了如下表的cachemanager实现。
实现任意一种cachemanager 的时候,需要注册实现cachemanager的bean,当然每种缓存技术都有很多额外的配置,但配置cachemanager 是必不可少的。
声明式缓存注解
spring提供了4个注解来声明缓存规则(又是使用注解式的aop的一个生动例子),如表。
开启声明式缓存
开启声明式缓存支持非常简单,只需要在配置类上使用@enabelcaching 注解即可。
springboot 的支持
在spring中国年使用缓存技术的关键是配置cachemanager 而springbok 为我门自动配置了多个cachemanager的实现。在spring boot 环境下,使用缓存技术只需要在项目中导入相关缓存技术的依赖包,并配置类使用@enabelcaching开启缓存支持即可。
小例子
小例子是使用 springboot+jpa +cache 实现的。
实例步骤目录
- 创建maven项目
- 数据库配置
- jpa配置和cache配置
- 编写bean 和dao层
- 编写service层
- 编写controller
- 启动cache
- 测试校验
1.创建maven项目
新建maven 项目pom.xml文件如下内容如下:
<?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"> <modelversion>4.0.0</modelversion> <groupid>com.us</groupid> <artifactid>springboot-cache</artifactid> <version>1.0-snapshot</version> <parent> <groupid>org.springframework.boot</groupid> <artifactid>spring-boot-starter-parent</artifactid> <version>1.3.0.release</version> </parent> <properties> <start-class>com.us.application</start-class> <maven.compiler.target>1.8</maven.compiler.target> <maven.compiler.source>1.8</maven.compiler.source> </properties> <!-- add typical dependencies for a web application --> <dependencies> <dependency> <groupid>org.springframework.boot</groupid> <artifactid>spring-boot-starter-cache</artifactid> </dependency> <dependency> <groupid>org.springframework.boot</groupid> <artifactid>spring-boot-starter-data-jpa</artifactid> </dependency> <dependency> <groupid>org.springframework.boot</groupid> <artifactid>spring-boot-starter-web</artifactid> </dependency> <dependency> <groupid>net.sf.ehcache</groupid> <artifactid>ehcache</artifactid> </dependency> <!--db--> <dependency> <groupid>mysql</groupid> <artifactid>mysql-connector-java</artifactid> <version>6.0.5</version> </dependency> <dependency> <groupid>com.mchange</groupid> <artifactid>c3p0</artifactid> <version>0.9.5.2</version> <exclusions> <exclusion> <groupid>commons-logging</groupid> <artifactid>commons-logging</artifactid> </exclusion> </exclusions> </dependency> </dependencies> </project>
2.数据库配置
在src/main/esouces目录下新建application.properties 文件,内容为数据库连接信息,如下:
application.properties
ms.db.driverclassname=com.mysql.jdbc.driver ms.db.url=jdbc:mysql://localhost:3306/cache?prepstmtcachesize=517&cacheprepstmts=true&autoreconnect=true&useunicode=true&characterencoding=utf-8&usessl=false&allowmultiqueries=true ms.db.username=root ms.db.password=xxxxxx ms.db.maxactive=500
新建dbconfig.java 配置文件,配置数据源
package com.us.example.config; /** * created by yangyibo on 17/1/13. */ import java.beans.propertyvetoexception; import org.springframework.beans.factory.annotation.autowired; import org.springframework.context.annotation.bean; import org.springframework.context.annotation.configuration; import org.springframework.core.env.environment; import com.mchange.v2.c3p0.combopooleddatasource; @configuration public class dbconfig { @autowired private environment env; @bean(name="datasource") public combopooleddatasource datasource() throws propertyvetoexception { combopooleddatasource datasource = new combopooleddatasource(); datasource.setdriverclass(env.getproperty("ms.db.driverclassname")); datasource.setjdbcurl(env.getproperty("ms.db.url")); datasource.setuser(env.getproperty("ms.db.username")); datasource.setpassword(env.getproperty("ms.db.password")); datasource.setmaxpoolsize(20); datasource.setminpoolsize(5); datasource.setinitialpoolsize(10); datasource.setmaxidletime(300); datasource.setacquireincrement(5); datasource.setidleconnectiontestperiod(60); return datasource; } }
数据库设计,数据库只有一张person表,设计如下:
3.jpa配置
spring-data- jpa 配置文件如下:
package com.us.example.config; import java.util.hashmap; import java.util.map; import javax.persistence.entitymanagerfactory; import javax.sql.datasource; import org.springframework.beans.factory.annotation.autowired; import org.springframework.context.annotation.bean; import org.springframework.context.annotation.componentscan; import org.springframework.context.annotation.configuration; import org.springframework.data.jpa.repository.config.enablejparepositories; import org.springframework.orm.jpa.jpatransactionmanager; import org.springframework.orm.jpa.localcontainerentitymanagerfactorybean; import org.springframework.orm.jpa.vendor.hibernatejpavendoradapter; import org.springframework.transaction.platformtransactionmanager; import org.springframework.transaction.annotation.enabletransactionmanagement; /** * created by yangyibo on 17/1/13. */ @configuration @enablejparepositories("com.us.example.dao") @enabletransactionmanagement @componentscan public class jpaconfig { @autowired private datasource datasource; @bean public entitymanagerfactory entitymanagerfactory() { hibernatejpavendoradapter vendoradapter = new hibernatejpavendoradapter(); localcontainerentitymanagerfactorybean factory = new localcontainerentitymanagerfactorybean(); factory.setjpavendoradapter(vendoradapter); factory.setpackagestoscan("com.us.example.bean"); factory.setdatasource(datasource); map<string, object> jpaproperties = new hashmap<>(); jpaproperties.put("hibernate.ejb.naming_strategy","org.hibernate.cfg.improvednamingstrategy"); jpaproperties.put("hibernate.jdbc.batch_size",50); factory.setjpapropertymap(jpaproperties); factory.afterpropertiesset(); return factory.getobject(); } @bean public platformtransactionmanager transactionmanager() { jpatransactionmanager txmanager = new jpatransactionmanager(); txmanager.setentitymanagerfactory(entitymanagerfactory()); return txmanager; } }
4.编写bean 和dao层
实体类 person.java
package com.us.example.bean; import javax.persistence.entity; import javax.persistence.generatedvalue; import javax.persistence.id; import javax.persistence.table; /** * created by yangyibo on 17/1/13. */ @entity @table(name = "person") public class person { @id @generatedvalue private long id; private string name; private integer age; private string address; public person() { super(); } public person(long id, string name, integer age, string address) { super(); this.id = id; this.name = name; this.age = age; this.address = address; } public long getid() { return id; } public void setid(long id) { this.id = id; } public string getname() { return name; } public void setname(string name) { this.name = name; } public integer getage() { return age; } public void setage(integer age) { this.age = age; } public string getaddress() { return address; } public void setaddress(string address) { this.address = address; } }
dao层,personrepository.java
package com.us.example.dao; import com.us.example.bean.person; import org.springframework.data.jpa.repository.jparepository; /** * created by yangyibo on 17/1/13. */ public interface personrepository extends jparepository<person, long> { }
5.编写service层
service 接口
package com.us.example.service; import com.us.example.bean.person; /** * created by yangyibo on 17/1/13. */ public interface demoservice { public person save(person person); public void remove(long id); public person findone(person person); }
实现:(重点,此处加缓存)
package com.us.example.service.impl; import com.us.example.bean.person; import com.us.example.dao.personrepository; import com.us.example.service.demoservice; import org.springframework.beans.factory.annotation.autowired; import org.springframework.cache.annotation.cacheevict; import org.springframework.cache.annotation.cacheput; import org.springframework.cache.annotation.cacheable; import org.springframework.stereotype.service; /** * created by yangyibo on 17/1/13. */ @service public class demoserviceimpl implements demoservice { @autowired private personrepository personrepository; @override //@cacheput缓存新增的或更新的数据到缓存,其中缓存名字是 people 。数据的key是person的id @cacheput(value = "people", key = "#person.id") public person save(person person) { person p = personrepository.save(person); system.out.println("为id、key为:"+p.getid()+"数据做了缓存"); return p; } @override //@cacheevict 从缓存people中删除key为id 的数据 @cacheevict(value = "people") public void remove(long id) { system.out.println("删除了id、key为"+id+"的数据缓存"); //这里不做实际删除操作 } @override //@cacheable缓存key为person 的id 数据到缓存people 中,如果没有指定key则方法参数作为key保存到缓存中。 @cacheable(value = "people", key = "#person.id") public person findone(person person) { person p = personrepository.findone(person.getid()); system.out.println("为id、key为:"+p.getid()+"数据做了缓存"); return p; } }
6.编写controller
为了测试方便请求方式都用了get
package com.us.example.controller; import com.us.example.bean.person; import com.us.example.service.demoservice; import org.springframework.beans.factory.annotation.autowired; import org.springframework.stereotype.controller; import org.springframework.web.bind.annotation.requestmapping; import org.springframework.web.bind.annotation.responsebody; import org.springframework.web.bind.annotation.restcontroller; /** * created by yangyibo on 17/1/13. */ @restcontroller public class cachecontroller { @autowired private demoservice demoservice; //http://localhost:8080/put?name=abel&age=23&address=shanghai @requestmapping("/put") public person put(person person){ return demoservice.save(person); } //http://localhost:8080/able?id=1 @requestmapping("/able") @responsebody public person cacheable(person person){ return demoservice.findone(person); } //http://localhost:8080/evit?id=1 @requestmapping("/evit") public string evit(long id){ demoservice.remove(id); return "ok"; } }
7.启动cache
启动类中要记得开启缓存配置。
package com.us.example; import org.springframework.boot.autoconfigure.springbootapplication; import org.springframework.cache.annotation.enablecaching; import org.springframework.context.configurableapplicationcontext; import org.springframework.context.annotation.componentscan; import static org.springframework.boot.springapplication.*; /** * created by yangyibo on 17/1/13. */ @componentscan(basepackages ="com.us.example") @springbootapplication @enablecaching public class application { public static void main(string[] args) { configurableapplicationcontext run = run(application.class, args); } }
8.测试校验检验able:
启动application 类,启动后在浏览器输入:http://localhost:8080/able?id=1(首先要在数据库中初始化几条数据。)
控制台输出:
“为id、key为:1数据做了缓存“ 此时已经为此次查询做了缓存,再次查询该条数据将不会出现此条语句,也就是不查询数据库了。
检验put
在浏览器输入:http://localhost:8080/put?name=abel&age=23&address=shanghai(向数据库插入一条数据,并将数据放入缓存。)
此时控制台输出为该条记录做了缓存:
然后再次调用able 方法,查询该条数据,将不再查询数据库,直接从缓存中读取数据。
测试evit
在浏览器输入:http://localhost:8080/evit?id=1(将该条记录从缓存中清楚,清除后,在次访问该条记录,将会重新将该记录放入缓存。)
控制台输出:
切换缓存
1.切换为ehcache作为缓存
pom.xml 文件中添加依赖
<dependency> <groupid>net.sf.ehcache</groupid> <artifactid>ehcache</artifactid> </dependency>
在resource 文件夹下新建ehcache的配置文件ehcache.xml 内容如下,此文件spring boot 会自动扫描
<?xml version="1.0" encoding="utf-8"?> <ehcache> <!--切换为ehcache 缓存时使用--> <cache name="people" maxelementsinmemory="1000" /> </ehcache>
2.切换为guava作为缓存
只需要在pom中添加依赖
<dependency> <groupid>com.google.guava</groupid> <artifactid>guava</artifactid> <version>18.0</version> </dependency>
3.切换为redis作为缓存
请看下篇博客
本文参考:《javaee开发的颠覆者:spring boot实战 》
本文源代码:https://github.com/527515025/springboot.git
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持。