Java 如何在Spring3中执行方法后强制@Cacheable工作？

我有一个将实体保存到数据库的方法。它是：

@Cacheable(value = EMPLOYEE_CACHE,key="#employee.id")
    public Employee createEmployee(Employee employee) {
        try {
            entityManager.persist(employee);
        } catch (Exception e) {
            return null;
        }
        return employee;
    }

我希望通过

Employee

的key=

id

缓存结果

Employee

。员工的

id

在运行

entityManager，persist

方法后分配。 我知道由于AOP，

@Cacheable

可以工作。默认情况下，在方法

createEmployee

运行之前，它将

employee

存储到缓存中

如何强制

org.springframework.cache.annotation.@Cacheable

在方法执行后存储到缓存中

堆栈跟踪：

java.lang.IllegalArgumentException: Null key returned for cache operation (maybe you are using named params on classes without debug info?) CachePutOperation[public com.livelessons.spring.springcore.entities.Employee com.livelessons.spring.springcore.service.EmployeeServiceImpl.createEmployee(com.livelessons.spring.springcore.entities.Employee)] caches=[employees] | key='#employee.id' | condition='' | unless=''
    at org.springframework.cache.interceptor.CacheAspectSupport.inspectCacheUpdates(CacheAspectSupport.java:371)
    at org.springframework.cache.interceptor.CacheAspectSupport.execute(CacheAspectSupport.java:202)
    at org.springframework.cache.interceptor.CacheInterceptor.invoke(CacheInterceptor.java:66)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
    at com.sun.proxy.$Proxy30.createEmployee(Unknown Source)
    at com.livelessons.spring.springcore.EmployeeServiceTest.saveEmployee(EmployeeServiceTest.java:59)
    at com.livelessons.spring.springcore.EmployeeServiceTest.testSpringCacheable(EmployeeServiceTest.java:51)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
    at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:74)
    at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:83)
    at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:231)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:88)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)
    at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
    at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:174)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)

---

您可以定义自己的注释，例如@DefferedCachable，然后使用aop以编程方式在缓存中存储/读取对象。

您应该使用

@CachePut

而不是

@Cacheable

（具有相同的属性）：

与{@Cacheable}注释相反

此注释不会导致跳过目标方法

相反，它总是导致调用方法并将其结果放入缓存中

---

有点晚了，但可能对某人有用。 @Cacheable从方法参数定义键，而不是返回值，因此，如果传递的是没有id的新Employee对象，则会得到null。 简单的解决方案可能如下所示：

public Employee createEmployeeWithCaching(Employee employee) {
    Employee employee = persistEmployee(employee);
    return saveEmployeeInCache(employee);   
}

private Employee persistEmployee(Employee employee) {
    try {
         return entityManager.persist(employee);
        } catch (Exception e) {
            return null;
        }
}

@Cacheable(value = EMPLOYEE_CACHE,key="#employee.id")
private Employee saveEmployeeInCache(Employee employee) {
    return employee;
}

---

但是，如果确实需要在

catch

块中返回

null

，请三思。显然，它将导致

saveEmployeeInCache

方法中的其他异常。

我在文档和我的代码@CachePut中将实体存储到缓存中，然后再执行方法。我在调用@CachePut方法时尝试了一个不为null的属性，它存储OK，但如果我将null属性

id

用作

CachePut

的

key

，则会引发异常。我甚至在@CachePut方法中显式地分配了id，并得到了相同的异常。请尝试调用

entityManager.flush（）

调用

persist（）

之后。它将为员工对象分配一个id。谢谢！这没有帮助，因为@CachePut在方法调用之前将存储放入缓存。查看stacktrace的编辑。