<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>

#项目端口配置
server.port=8080
server.address=0.0.0.0

spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/ssm?characterEncoding=UTF8&useSSL=false&serverTimezone=UTC
spring.datasource.username=root
spring.datasource.password=root

spring.datasouce.type=com.alibaba.druid.pool.DruidDataSource

spring.jpa.hibernate.ddl-auto=update
spring.jpa.show-sql=true

spring.devtools.restart.enabled=true

spring.cache.ehcache.config=classpath:ehcache.xml

package com.bjsxt;

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

@SpringBootApplication
@EnableCaching//启用缓存机制
public class BootDataApplication {

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

}

package com.bjsxt.service.impl;

import com.bjsxt.dao.UserDao;
import com.bjsxt.pojo.Users;
import com.bjsxt.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cache.annotation.CacheEvict;
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;

@Service
public class UserServiceImpl implements UserService {

    @Autowired
    UserDao ud;

    @Override
    @CacheEvict(value = "users",allEntries = true)//清空缓存
    public void addUser(Users users) {
        ud.save(users);
    }

    @Override
    @Cacheable(value = "users")//配置缓存，查找缓存文件
    public List<Users> findall() {
        List<Users> usersList = ud.findAll();
        return usersList;
    }

    @Override
    @Cacheable(value = "users",key = "#pageable.pageSize")//配置缓存，配置缓存的key
    public Page<Users> findUserByPage(Pageable pageable) {
        Page<Users> usersPage = ud.findAll(pageable);
        return usersPage;
    }


}

package com.bjsxt.pojo;

import lombok.Data;

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

@Entity
@Table(name = "users")
@Data
public class Users implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "userid")
    private int userid;

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

    @Column(name = "userage")
    private int userage;

    public Users(){}
    public Users(String username, int userage) {
        this.username = username;
        this.userage = userage;
    }
}

package com.bjsxt.test;
import com.bjsxt.BootDataApplication;
import com.bjsxt.dao.UserDao;
import com.bjsxt.pojo.Users;
import com.bjsxt.service.UserService;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Pageable;
import org.springframework.data.jpa.domain.Specification;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

import javax.persistence.criteria.CriteriaBuilder;
import javax.persistence.criteria.CriteriaQuery;
import javax.persistence.criteria.Predicate;
import javax.persistence.criteria.Root;
import java.util.ArrayList;
import java.util.List;

@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(classes = BootDataApplication.class)
public class UserTest {

    @Autowired
    UserService us;

    @Autowired
    UserDao ud;


    /**
     * 添加用户
     */
    @Test
    public void TestAddUser(){
        Users users=new Users();
        users.setUsername("杨彪");
        users.setUserage(27);
        us.addUser(users);
    }

    @Test
    public void findByNameAndAge(){
        Specification<Users> spec=new Specification<Users>() {
            @Override
            public Predicate toPredicate(Root<Users> root, CriteriaQuery<?> criteriaQuery, CriteriaBuilder criteriaBuilder) {
                /*List<Predicate> predicates=new ArrayList<>();
                predicates.add(criteriaBuilder.equal(root.get("username"),"asd"));
                predicates.add(criteriaBuilder.equal(root.get("userage"),"123"));
                Predicate[] arr=new Predicate[predicates.size()];
                return criteriaBuilder.and(predicates.toArray(arr));*/
               return criteriaBuilder.or(criteriaBuilder.equal(root.get("username"),"asd"),criteriaBuilder.equal(root.get("userage"),"22"));
            }
        };
        List<Users> users = ud.findAll(spec);
        for (Users user : users) {
            System.out.println(user);
        }
    }

    /**
     * 测试使用缓存查询所有，第二次不会打印sql语句
     */
    @Test
    public void TestFindAll(){
        System.out.println("第一次查询：");
        List<Users> users = us.findall();
        for (Users user : users) {
            System.out.println("First:"+user);
        }
        Users use=new Users();
        use.setUsername("杨彪3");
        use.setUserage(22);
        us.addUser(use);

        System.out.println("n第二次查询：");
        List<Users> u = us.findall();
        for (Users user : u) {
            System.out.println("Second:"+user);
        }

    }

    @Test
    public void findUserByPage(){
        Pageable pageable=new PageRequest(0,2);

        System.out.println("第一次查询：");
        Page<Users> userByPage = us.findUserByPage(pageable);
        long totalElements = userByPage.getTotalElements();
        System.out.println("First总条数："+totalElements);

        System.out.println("n第二次查询：");
        Page<Users> userByPage2 = us.findUserByPage(pageable);
        long totalElements2 = userByPage2.getTotalElements();
        System.out.println("Second总条数："+totalElements2);


        System.out.println("n第三次查询：");
        pageable=new PageRequest(1,2);
        Page<Users> userByPage3 = us.findUserByPage(pageable);
        long totalElements3 = userByPage3.getTotalElements();
        System.out.println("Third总条数："+totalElements3);
    }

}