guava快取的使用及與spring的整合
阿新 • • 發佈：2019-02-15
一、guava快取簡介
guava是google為java開發的庫，對jdk進行了擴充套件。在此我們只介紹guava的快取。
guava快取是記憶體快取，也就是資料存在記憶體中的。
二、guava基本使用
1、新增maven依賴
<dependency> <groupId>com.google.guava</groupId> <artifactId>guava</artifactId> <version>23.0</version> </dependency>
2、自定義guava工具類
public class GuavaCacheUtil { public static LoadingCache<String, String> strCache = CacheBuilder .newBuilder() .maximumSize(1000) .expireAfterAccess(5, TimeUnit.MINUTES) .build( new CacheLoader<String, String>() { @Overridepublic String load(String s) throws Exception { //當快取中不存在時，自動載入新資料到快取 return null; } } ); /** * 將值存入快取 * * @param key * @param val */ public static void setStr(String key, String val) { strCache.put(key, val); } /** * 從快取中取值 * * @paramkey * @return */ public static String getStr(String key) { String val = ""; try { val = strCache.get(key); } catch (ExecutionException e) { } return val; } }
3、使用
public class GuavaCacheMain { public static void main(String[] args) { String key = "k1"; String val = "v1"; GuavaCacheUtil.setStr(key, val); String v1 = GuavaCacheUtil.getStr(key); System.out.println("k1 : " + v1); String v2 = GuavaCacheUtil.getStr(key); System.out.println("k2 : " + v2); } }輸出：
k1 : v1
k1 : v1
三、guava快取與spring的整合
1、新增maven依賴
<dependency> <groupId>com.google.guava</groupId> <artifactId>guava</artifactId> <version>23.0</version> </dependency>2、在spring中配置guava快取
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xmlns:cache="http://www.springframework.org/schema/cache" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/cache http://www.springframework.org/schema/cache/spring-cache.xsd "> <context:component-scan base-package="com.dragon.study" /> <cache:annotation-driven /> <bean id="cacheManager" class="org.springframework.cache.guava.GuavaCacheManager"> <property name="cacheSpecification" value="concurrencyLevel=4,expireAfterAccess=100s,expireAfterWrite=100s" /> <property name="cacheNames"> <list> <value>guavaCache</value> </list> </property> </bean> </beans>3、在服務中使用guava快取
public interface StudentService { public Student getStudent(Integer id); public Student updateStudent(Student stu); public void deleteStudent(Integer id); public void deleteAllStudent(); public void myDelete(Integer id); }
@Service("studentGuavaCache") public class StudentGuavaCacheImpl implements StudentService { @Cacheable(value = "guavaCache",key="'id_'+#id",condition = "#id<3") public Student getStudent(Integer id) { Student stu = new Student(); stu.setId(id); stu.setName("apple"); return stu; } @CachePut(value = "guavaCache",key="'id_'+#stu.getId()") public Student updateStudent(Student stu){ System.out.println("update stu"); return stu; } @CacheEvict(value = "guavaCache",key="'id_'+#id") public void deleteStudent(Integer id){ System.out.println("delete student "+id); } public void myDelete(Integer id){ try { StudentService ss = (StudentService) AopContext.currentProxy(); ss.deleteStudent(id); return ; }catch (Exception e){ e.printStackTrace(); } this.deleteStudent(id); } @CacheEvict(value = "guavaCache",allEntries = true) public void deleteAllStudent(){ System.out.println("delete all student "); } }4、測試
public class SpringGuavaCacheMain { public static void main(String[] args) { ClassPathXmlApplicationContext ac = new ClassPathXmlApplicationContext("classpath:spring-guava-cache.xml"); StudentService studentService = (StudentService) ac.getBean("studentGuavaCache"); Integer id =1; Student stu = studentService.getStudent(id); //新建快取 stu = studentService.getStudent(id); //從快取中取 studentService.myDelete(id); stu = studentService.getStudent(id); //從快取中取 stu.setName("banana"); //重新設定值 studentService.updateStudent(stu); //更新快取 stu = studentService.getStudent(id); //從快取中取出新值 stu = new Student(); //新例項 stu.setId(0); studentService.updateStudent(stu); //用新建的例項進行更新，會新建快取 stu = studentService.getStudent(0); //從快取中取 studentService.deleteStudent(id); // 刪除快取 stu = studentService.getStudent(id); //再次新建快取 id=2; stu = studentService.getStudent(id); //新建快取 studentService.deleteAllStudent(); //刪除所有快取 id=1; stu = studentService.getStudent(id); //因所有快取被前一步清除，會新建快取 id=5; stu = studentService.getStudent(id); //不會新建快取 因為設定了快取條件必須小於3 stu = studentService.getStudent(id); //因沒有快取，不會從快取中取 Assert.notNull(stu); } }輸出：
delete student 1
update stu
update stu
delete student 1
delete all student
四、guava快取與其它形式快取共存
除了guava快取，在還有其它如redis等快取，使用方法類似，在此僅列出其spring的配置檔案
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xmlns:cache="http://www.springframework.org/schema/cache" xmlns:p="http://www.springframework.org/schema/p" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/cache http://www.springframework.org/schema/cache/spring-cache.xsd "> <context:component-scan base-package="com.dragon.study" /> <cache:annotation-driven /> <bean id="cacheManager" class="org.springframework.cache.support.CompositeCacheManager"> <property name="cacheManagers"> <list> <ref bean="simpleCacheManager" /> <ref bean="guavaCacheManager" /> </list> </property> <property name="fallbackToNoOpCache" value="true" /> </bean> <bean id="simpleCacheManager" class="org.springframework.cache.support.SimpleCacheManager"> <property name="caches"> <set> <bean class="org.springframework.cache.concurrent.ConcurrentMapCacheFactoryBean" p:name="default" /> <bean class="org.springframework.cache.concurrent.ConcurrentMapCacheFactoryBean" p:name="mycache" /> <bean class="com.dragon.tbscheduleStudy.cache.RedisCache" p:name="redisCache" p:timeout="60000" /> </set> </property> </bean> <bean id="guavaCacheManager" class="org.springframework.cache.guava.GuavaCacheManager"> <property name="cacheSpecification" value="concurrencyLevel=4,expireAfterAccess=100s,expireAfterWrite=100s" /> <property name="cacheNames"> <list> <value>guavaCache</value> </list> </property> </bean> </beans>