springboot利用AOP自定义注解的方式提供redis缓存
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添加pom文件支持
4.0.0 com.sg cristina 0.0.1-SNAPSHOT cristina El psy congroo org.springframework.boot spring-boot-starter-parent 2.0.3.RELEASE UTF-8 UTF-8 1.8 commons-io commons-io 2.4 commons-lang commons-lang 2.5 com.alibaba druid 1.1.9 com.alibaba fastjson 1.2.46 org.springframework.boot spring-boot-starter-web com.github.pagehelper pagehelper 4.0.0 org.apache.zookeeper zookeeper 3.4.8 com.github.sgroschupf zkclient 0.1 com.alibaba dubbo 2.8.4 org.springframework.boot spring-boot-configuration-processor true org.springframework.boot spring-boot-starter-test test org.mybatis.spring.boot mybatis-spring-boot-starter 1.3.2 mysql mysql-connector-java org.projectlombok lombok 1.16.22 io.springfox springfox-swagger2 2.7.0 io.springfox springfox-swagger-ui 2.7.0 org.aspectj aspectjweaver 1.8.13 org.springframework.boot spring-boot-starter-data-redis redis.clients jedis 2.8.1 org.apache.httpcomponents httpclient 4.5 org.springframework.boot spring-boot-maven-plugin org.mybatis.generator mybatis-generator-maven-plugin 1.3.2 ${basedir}/src/main/resources/generator/generatorConfig.xml true true -
springboot开启AOP
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@EnableAspectJAutoProxy @SpringBootApplication @MapperScan("com.sg.cristina.dao") public class CristinaApplication { public static void main(String[] args) { SpringApplication.run(CristinaApplication.class, args); } } -
自定义用于添加缓存的注解和用户删除缓存的注解
/** * Created by jw on 19/3/29. * @usage 缓存注解类 */ @Retention(RetentionPolicy.RUNTIME) @Target(ElementType.METHOD) @Documented public @interface Cacheable { String key(); String fieldKey() ; int expireTime() default 3600; } /** * Created by jw on 19/3/29. * * @usage 清除过期缓存注解，放置于update delete insert 类型逻辑之上 */ @Retention(RetentionPolicy.RUNTIME) @Target(ElementType.METHOD) public @interface CacheEvict { String key(); String fieldKey() ; int expireTime() default 3600; } -
切面逻辑
import java.lang.reflect.Method; /** * Created by jw on 19/3/29. */ @Aspect @EnableAspectJAutoProxy @Component public class RedisCacheAspect { private static final Logger logger = Logger.getLogger(RedisCacheAspect.class); /** * 分隔符 **/ private static final String DELIMITER = "|"; @Autowired RedisUtil redisUtil; /** * Service层切点 使用到了我们定义的 Cacheable 作为切点表达式。 * 而且我们可以看出此表达式基于 annotation。 * 并且用于内建属性为查询的方法之上 */ @Pointcut("@annotation(com.sg.cristina.config.aspect.Cacheable)") public void queryCache() { } /** * Service层切点 使用到了我们定义的 RedisEvict 作为切点表达式。 * 而且我们可以看出此表达式是基于 annotation 的。 * 并且用于内建属性为非查询的方法之上，用于更新表 */ @Pointcut("@annotation(com.sg.cristina.config.aspect.CacheEvict)") public void ClearCache() { } @Around("queryCache()") public Object Interceptor(ProceedingJoinPoint pjp) throws Throwable { Object result = null; System.out.println("query cache -------------------------------"); Method method = getMethod(pjp); //获取被切方法的注解 Cacheable cacheable = method.getAnnotation(Cacheable.class); //key的value String fieldKey = parseKey(cacheable.fieldKey(), method, pjp.getArgs()); //使用redis 的hash进行存取，类似于一张表 result = redisUtil.hget(cacheable.key(), fieldKey); if (result == null) { //如果缓存没有则执行原本逻辑 System.out.println("cache is empty ,query db--------"); try { result = pjp.proceed(); System.out.println("get result from db ----------"); //从db查询到了则再加入缓存 if (result != null) { redisUtil.hset(cacheable.key(), fieldKey, result); System.out.println("set result to cache ----------"); } } catch (Throwable e) { e.printStackTrace(); logger.error(e.getMessage()); } } return result; } /*** 定义清除缓存逻辑*/ @Around(value = "ClearCache()") public Object evict(ProceedingJoinPoint pjp) throws Throwable { Object result = null; System.out.println("clear cache ---------------"); Method method = getMethod(pjp); CacheEvict cacheEvict = method.getAnnotation(CacheEvict.class); String fieldKey = parseKey(cacheEvict.fieldKey(), method, pjp.getArgs()); //先删除缓存 redisUtil.hdel(cacheEvict.key(), fieldKey); //然后操作db result = pjp.proceed(); return result; } /** * 获取被拦截方法对象 ** MethodSignature.getMethod() 获取的是顶层接口或者父类的方法对象 * 而缓存的注解在实现类的方法上 * 所以应该使用反射获取当前对象的方法对象 */ public Method getMethod(ProceedingJoinPoint pjp) { //获取参数的类型 Object[] args = pjp.getArgs(); Class[] argTypes = new Class[pjp.getArgs().length]; for (int i = 0; i < args.length; i++) { argTypes[i] = args[i].getClass(); } Method method = null; try { Object target = pjp.getTarget(); Class aClass = target.getClass(); Signature signature = pjp.getSignature(); method = aClass.getMethod(signature.getName(), argTypes); } catch (NoSuchMethodException e) { e.printStackTrace(); logger.error(e.getMessage()); } catch (SecurityException e) { e.printStackTrace(); logger.error(e.getMessage()); } return method; } /** * 获取缓存的key * key 定义在注解上，支持SPEL表达式 * * @param * @return */ private String parseKey(String key, Method method, Object[] args) { //获取被拦截方法参数名列表(使用Spring支持类库) LocalVariableTableParameterNameDiscoverer u = new LocalVariableTableParameterNameDiscoverer(); String[] paraNameArr = u.getParameterNames(method); //使用SPEL进行key的解析 ExpressionParser parser = new SpelExpressionParser(); //SPEL上下文 StandardEvaluationContext context = new StandardEvaluationContext(); //把方法参数放入SPEL上下文中 for (int i = 0; i < paraNameArr.length; i++) { context.setVariable(paraNameArr[i], args[i]); } return parser.parseExpression(key).getValue(context, String.class); } }
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注解使用方式及注意事项
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这种注解方式适用于单表的增删改查，一般以id(唯一标示)作为缓存的要素，如果将连表查询的结果缓存到redis那么对缓存的对象有一定的要求，如：读的频率高，且改动少。
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本次采用的缓存逻辑是在service层对select类方法进行先查缓存再查db处理，如果缓存没查到，那么执行db查询，然后将查到的结果缓存到redis，对update的方法和delete的方法统一采用先删除缓存然后修改db
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使用方法参考：
/** * @Author: jiangwei * @Date: 2019/4/20 * @Desc: */ @Service public class UserServiceImpl implements UserService { @Autowired SgUserMapper userMapper ; /** * @param sgId * @mbggenerated */ @CacheEvict(key = "SgUser",fieldKey = "#sgId") @Override public int deleteByPrimaryKey(Integer sgId) { return userMapper.deleteByPrimaryKey(sgId); } /** * @param record * @mbggenerated */ @Override public int insert(SgUser record) { return userMapper.insert(record); } /** * @param record * @mbggenerated */ @CacheEvict(key = "SgUser",fieldKey = "#record.sgId") @Override public int insertSelective(SgUser record) { return userMapper.insertSelective(record); } /** * @param sgId * @mbggenerated */ @Cacheable(key = "SgUser",fieldKey = "#sgId") @Override public SgUser selectByPrimaryKey(Integer sgId) { return userMapper.selectByPrimaryKey(sgId); } /** * @param record * @mbggenerated */ @CacheEvict(key = "SgUser",fieldKey = "#record.sgId") @Override public int updateByPrimaryKeySelective(SgUser record) { return userMapper.updateByPrimaryKeySelective(record); } /** * @param record * @mbggenerated */ @CacheEvict(key = "SgUser",fieldKey = "#record.sgId") @Override public int updateByPrimaryKey(SgUser record) { return userMapper.updateByPrimaryKey(record); } @Override public SgUser selectByGitId(String gitId) { return userMapper.selectByGitId(gitId); } }
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