Springboot integrates EHcache to implement paging caching

A brief overview

@Cacheable caches the current object

@Cacheable Function: Add the return value of the method to Ehcache for caching

@Cacheable （value=“xxx”，key="xxxx"）

Value attribute: specify a cache strategy in the Ehcache configuration file, if no value is given, then the default cache strategy is used

The role of the key: give a name to the stored value, and if the name is the same in the query, the value is taken from the known name. Otherwise, re-query the database.

Two cases

2.1 Engineering structure

2.2 pom file

    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.13</version>
      <scope>test</scope>
    </dependency>
    <!-- springBoot 的启动器 -->
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <!-- springBoot 的启动器 -->
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-thymeleaf</artifactId>
    </dependency>
    <!-- springBoot 的启动器 -->
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>
    <!-- 测试工具的启动器 -->
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-test</artifactId>
    </dependency>
    <!-- mysql -->
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
    </dependency>
    <!-- druid连接池 -->
    <dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>druid</artifactId>
      <version>1.1.10</version>
    </dependency>
    <!-- Spring Boot 缓存支持启动器 -->
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-cache</artifactId>
    </dependency>
    <!-- Ehcache 坐标 -->
    <dependency>
      <groupId>net.sf.ehcache</groupId>
      <artifactId>ehcache</artifactId>
    </dependency>

2.3 dao

package com.ljf.spring.boot.demo.dao;

import com.ljf.spring.boot.demo.model.Users;
import org.springframework.data.jpa.repository.JpaRepository;

/**
 * 参数一 T :当前需要映射的实体
 * 参数二 ID :当前映射的实体中的OID的类型
 *
 */
public interface UserRepository extends JpaRepository<Users,Integer> {

}

2.4 model

package com.ljf.spring.boot.demo.model;

import javax.persistence.*;
import java.io.Serializable;

/**
 * @ClassName: Users
 * @Description: TODO
 * @Author: liujianfu
 * @Date: 2020/09/02 08:50:18 
 * @Version: V1.0
 **/
    @Entity
    @Table(name="tb_users_tb")
    public class Users implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id")
    private Integer id;

    @Column(name = "name")
    private String name;

    @Column(name = "age")
    private Integer age;

    @Column(name = "address")
    private String address;


    public Integer getId() {
        return id;
    }

    public void setId(Integer 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;
    }

    @Override
    public String toString() {
        return "Users [id=" + id + ", name=" + name + ", age=" + age + ", address=" + address + "]";
    }
}

2.5 service

Interface layer:

package com.ljf.spring.boot.demo.service;

import com.ljf.spring.boot.demo.model.Users;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;

import java.util.List;

public interface UserService {
    List<Users> findUserAll();
    public Page<Users> findUserByPage(Pageable pageable );
}

Implementation layer:

package com.ljf.spring.boot.demo.service.impl;

import com.ljf.spring.boot.demo.dao.UserRepository;
import com.ljf.spring.boot.demo.model.Users;
import com.ljf.spring.boot.demo.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import org.springframework.stereotype.Service;

import java.util.List;

/**
 * @ClassName: UserServiceImpl
 * @Description: TODO
 * @Author: liujianfu
 * @Date: 2020/09/02 08:57:11 
 * @Version: V1.0
 **/
@Service
public class UserServiceImpl  implements UserService {
    @Autowired
    private UserRepository userRepository;
    @Override
    //@Cacheable 对当前的对象做缓存处理
    //@Cacheable 作用：把方法的返回值添加到 Ehcache 中做缓存
    // Value 属性：指定一个 Ehcache 配置文件中的缓存策略，如果没有给定 value，那么则表示使用默认的缓存策略
    @Cacheable(value = "users")
    public List<Users> findUserAll() {
        return this.userRepository.findAll();
    }

   // @Cacheable(value="users",key="#pageable") //默认key的值为pageable
   // @Cacheable(value="users",key="#pageable.pageSize") //指定key的值为#pageable.pageSize
    public Page<Users> findUserByPage(Pageable pageable ){
        return this.userRepository.findAll(pageable);
    }

}

2.6 Configuration file

1.application configuration file

#spring的配置mysql
spring.datasource.driverClassName=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/test_db?serverTimezone=UTC
spring.datasource.username=root
spring.datasource.password=root
#ali
spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
spring.jpa.hibernate.ddl-auto=update
spring.jpa.show-sql=true
spring.cache.ehcache.cofnig=ehcache.xml

2.ehcache cache file

<ehcache xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../config/ehcache.xsd">

    <diskStore path="java.io.tmpdir"/>

  <!--defaultCache:echcache的默认缓存策略  -->
    <defaultCache
            maxElementsInMemory="10000"
            eternal="false"
            timeToIdleSeconds="120"
            timeToLiveSeconds="120"
            maxElementsOnDisk="10000000"
            diskExpiryThreadIntervalSeconds="120"
            memoryStoreEvictionPolicy="LRU">
        <persistence strategy="localTempSwap"/>
    </defaultCache>
    <!-- 自定义缓存策略 -->
    <cache name="users"
            maxElementsInMemory="10000"
            eternal="false"
            timeToIdleSeconds="120"
            timeToLiveSeconds="120"
            maxElementsOnDisk="10000000"
            diskExpiryThreadIntervalSeconds="120"
            memoryStoreEvictionPolicy="LRU">
        <persistence strategy="localTempSwap"/>
    </cache>
</ehcache>

2.7 Startup class

package com.ljf.spring.boot.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
import org.springframework.boot.autoconfigure.jdbc.DataSourceTransactionManagerAutoConfiguration;
import org.springframework.cache.annotation.EnableCaching;

/**
 * Hello world!
 *
 */
@SpringBootApplication
@EnableCaching
public class StartApp
{
    public static void main( String[] args )
    {
        SpringApplication.run(StartApp.class, args);
        System.out.println( "Hello World!" );

    }
}

2.8 Test category

    @Test
    public void queryByPage(){
        Pageable pageable= PageRequest.of(0, 10);
        Page<Users> list=us.findUserByPage(pageable);
        System.out.println("第1次:"+list.getContent().get(0).getAddress());
        Page<Users> list2=us.findUserByPage(pageable);
        System.out.println("第2次:"+list2.getContent().get(0).getAddress());
         pageable= PageRequest.of(0, 5);
        Page<Users> list3=us.findUserByPage(pageable);
        System.out.println("第3次:"+list3.getContent().get(0).getAddress());
    }

Without caching, the query was executed 3 times to query the database

2.9 Add cache

In the paging method, if cached, the pageable that has been paged is used as the key

Through the execution results, we can see that the database is queried for the first time, and the memory is queried for the second time. When the paging pageable = PageRequest.of(0, 10); is changed to pageable = PageRequest.of(0, 5);, when it is executed again, Re-query the database