[项目系列文章说明]: 该类型的文章是对项目的实现方案和部分代码进行说明.
除了使用Spring cache之外, 项目对自定义缓存扩展有一定需求的情况下, 自己动手编写一个针对方法级别的缓存(可扩展支持到类,但不易维护, 不建议使用类级别的).
结合STC-stcconfig动态配置系统, 可实现缓存的动态删除, 缓存开关实时生效.
代码地址: https://github.com/lvxingzhi/stcdatacache
系统实现原理
利用Spring 提供的AOP机制,实现对方法的扩展.
利用Spel表达式实现方法入参与缓存key动态匹配.
预定义缓存接口,实现对不同缓存方式的兼容.
异常处理保证业务的可用性.
整理并不复杂, 流程图略.
依赖
1, Spring
2, 任意分布式缓存
目录结构
annotation: 注解
aspect: 注解处理器
cache: 缓存接口定义和本地实现案例
test: 测试Demo
核心代码
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| /**
* STCDataCache处理器
*
* @Author xingzhi.lv
* @Version 2.1
* @Date 2021/11/3 11:02
*/
@Aspect
@Component
public class STCDataCacheAspect {
private static final Logger logger = LoggerFactory.getLogger(STCDataCacheAspect.class);
public static final ExpressionParser EXPRESSION_PARSER = new SpelExpressionParser();
public static final String KEY_SPLIT = "_";
private STCCacheTemplate cacheTemplate = new STCCacheLocalTemplate();
public static final String STCNULL = "STCNULL";
// 缓存切面
@Pointcut("@annotation(com.note.stcdatacache.annotation.STCDataCache)")
public void methodCachePoint() {
}
// 删除缓存切面
@Pointcut("@annotation(com.note.stcdatacache.annotation.STCDataCacheDelete)")
public void methodCacheDeletePoint() {
}
@Around(value = "methodCachePoint()")
public Object around(ProceedingJoinPoint joinPoint) throws Throwable {
try {
MethodSignature signature = (MethodSignature) joinPoint.getSignature();
Method method = signature.getMethod();
STCDataCache cacheAnno = AnnotationUtils.findAnnotation(method, STCDataCache.class);
String keyEL = cacheAnno.cacheKey();
Object[] args = joinPoint.getArgs();
String[] argNames = signature.getParameterNames();
// 使用Spel解析
EvaluationContext context = new StandardEvaluationContext();
String cacheKey;
if (Strings.isNotEmpty(keyEL)) {
if (args != null && args.length > 0) {
for (int i = 0; i < argNames.length; i++) {
context.setVariable(argNames[i], args[i]);
}
}
Object obj = EXPRESSION_PARSER.parseExpression(keyEL).getValue(context);
cacheKey = obj.toString();
} else {
String className = joinPoint.getSignature().getDeclaringTypeName();
String methodName = joinPoint.getSignature().getName();
cacheKey = className + KEY_SPLIT + methodName;
}
String group = cacheAnno.group();
cacheKey = group + KEY_SPLIT + cacheKey;
// 读取缓存数据
Object cacheResult = cacheTemplate.get(cacheKey);
if (cacheResult != null && !STCNULL.equals(cacheResult)) {
return cacheResult;
}
// 空占位符
if (STCNULL.equals(cacheResult)) {
return null;
}
final Object result = joinPoint.proceed();
if (Objects.isNull(result)) {
cacheTemplate.set(cacheKey, STCNULL);
} else {
cacheTemplate.set(cacheKey, result);
}
return result;
} catch (Throwable ta) {
logger.error("STCDataCache read cache error", ta);
return joinPoint.proceed();
}
}
@Around(value = "methodCacheDeletePoint()")
public Object deleteAround(ProceedingJoinPoint joinPoint) throws Throwable {
try {
MethodSignature signature = (MethodSignature) joinPoint.getSignature();
Method method = signature.getMethod();
STCDataCacheDelete cacheAnno = AnnotationUtils.findAnnotation(method, STCDataCacheDelete.class);
String keyEL = cacheAnno.cacheKey();
Object[] args = joinPoint.getArgs();
String[] argNames = signature.getParameterNames();
// 使用Spel解析
EvaluationContext context = new StandardEvaluationContext();
String cacheKey;
if (Strings.isNotEmpty(keyEL)) {
if (args != null && args.length > 0) {
for (int i = 0; i < argNames.length; i++) {
context.setVariable(argNames[i], args[i]);
}
}
Object obj = EXPRESSION_PARSER.parseExpression(keyEL).getValue(context);
cacheKey = obj.toString();
} else {
String className = joinPoint.getSignature().getDeclaringTypeName();
String methodName = joinPoint.getSignature().getName();
cacheKey = className + KEY_SPLIT + methodName;
}
String group = cacheAnno.group();
cacheKey = group + KEY_SPLIT + cacheKey;
// 删除缓存数据
cacheTemplate.delete(cacheKey);
} catch (Throwable ta) {
logger.error("STCDataCache delete cache error", ta);
}
return joinPoint.proceed();
}
public STCCacheTemplate getCacheTemplate() {
return cacheTemplate;
}
public void setCacheTemplate(STCCacheTemplate cacheTemplate) {
this.cacheTemplate = cacheTemplate;
}
|
测试
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| @SpringBootTest
class StcdatacacheApplicationTests {
@Resource
private DemoService demoService;
@Test
void contextLoads() {
String demoName1 = demoService.findDemoName(58);
System.out.println(demoName1);
String demoName2 = demoService.findDemoName(58);
System.out.println(demoName2);
demoService.deleteDemoDelete(58);
String demoName3 = demoService.findDemoName(58);
System.out.println(demoName3);
}
}
|
结果
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| DemoName : -2094750780
DemoName : -2094750780
DemoName : 336840328
|