框架代码中出现这个空指针的原因是什么？我最近开始将我们的一些应用程序堆栈从带有 JGroups 的 ehcache 迁移到 Redis。作为其中的一部分，我们将继续使用 ehcache 作为某些功能的二级缓存。在一些 集成测试(约 900 个)期间，我在客户端库(Jedis 或 Lettuce)的连接代码中得到了一致的 NullPointerExceptions。但是，缓存机制在正常应用程序运行期间确实起作用，并且缓存在某些集成测试期间正常工作。现有的应用程序代码使用了@Cacheable，这对我来说效果很好。我使用以下 gradle 依赖项和缓存配置进行了集成:

compile 'org.springframework.data:spring-data-redis:1.6.0.RELEASE'
compile 'biz.paluch.redis:lettuce:'3.3.Final'

redisContext.xml

<bean id="lettucePool" class="org.springframework.data.redis.connection.lettuce.DefaultLettucePool">
  <property name="hostName" value="${redis.host}" />
  <property name="port" value="${redis.port}" />
  <property name="poolConfig" ref="lettucePoolConfiguration" />
</bean> 

<bean id="lettucePoolConfiguration" class="org.springframework.data.redis.connection.PoolConfig">
  <property name="maxIdle" value="900"/>
  <property name="maxActive" value="1000" />
  <property name="maxTotal" value="1200" />
  <property name="testOnBorrow" value="true" />
  <property name="testOnReturn" value="true" />
</bean>

<bean id="lettuceConnectionFactory" class="org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory" p:host-name="${redis.host}" p:port="${redis.port}">
    <constructor-arg index="0" ref="lettucePool"/>
    <property name="validateConnection" value="true"></property>
    <property name="shareNativeConnection" value="true"></property>
</bean>

<bean id="redisTemplate" class="org.springframework.data.redis.core.RedisTemplate" p:connection-factory-ref="lettuceConnectionFactory">
    <property name="keySerializer">
        <bean class="c.h.c.c.util.MultiKeySerializer"/> <!-- Used to translate SPeL array to key String -->
    </property>
    <property name="hashKeySerializer">
        <bean class="org.springframework.data.redis.serializer.StringRedisSerializer"/>
    </property>
</bean>

<bean id="redisCacheManager" class="org.springframework.data.redis.cache.RedisCacheManager">
    <constructor-arg index="0" ref="redisTemplate"></constructor-arg>
    <property name="cacheNames">
        <set>
            <value>cachenames......</value>
        </set>
    </property>
    <property name="expires">
        <map>
            <entry key="cachenames......" value="times...."/>
        </map>
    </property>
</bean>

缓存上下文文件

<cache:annotation-driven cache-manager="ehcacheManager"/>
<cache:annotation-driven cache-manager="redisCacheManager"/>

<bean id="ehcacheManager" class="org.springframework.cache.ehcache.EhCacheCacheManager">
    <property name="cacheManager" ref="ehcache" />
</bean>

<bean id="ehcache" class="org.springframework.cache.ehcache.EhCacheManagerFactoryBean">
    <property name="configLocation" value="classpath:ehcache.xml" />
    <property name="acceptExisting" value="true" />
</bean>

<bean id="userCacheInstance" factory-bean="ehcacheManager" factory-method="getCache">
    <constructor-arg value="user" />
</bean>

<import resource="classpath:redisContext.xml />

异常(exception):

org.springframework.data.redis.RedisSystemException: Unknown redis exception; nested exception is java.lang.NullPointerException
at org.springframework.data.redis.FallbackExceptionTranslationStrategy.getFallback(FallbackExceptionTranslationStrategy.java:48)
at org.springframework.data.redis.FallbackExceptionTranslationStrategy.translate(FallbackExceptionTranslationStrategy.java:38)
at org.springframework.data.redis.connection.lettuce.LettuceConnection.convertLettuceAccessException(LettuceConnection.java:305)
at org.springframework.data.redis.connection.lettuce.LettuceConnection.get(LettuceConnection.java:1175)
at sun.reflect.GeneratedMethodAccessor353.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.springframework.data.redis.core.CloseSuppressingInvocationHandler.invoke(CloseSuppressingInvocationHandler.java:57)
at com.sun.proxy.$Proxy137.get(Unknown Source)
at org.springframework.data.redis.cache.RedisCache$1.doInRedis(RedisCache.java:110)
at org.springframework.data.redis.cache.RedisCache$1.doInRedis(RedisCache.java:106)
at org.springframework.data.redis.cache.RedisCache$AbstractRedisCacheCallback.doInRedis(RedisCache.java:424)
at org.springframework.data.redis.core.RedisTemplate.execute(RedisTemplate.java:191)
at org.springframework.data.redis.core.RedisTemplate.execute(RedisTemplate.java:153)
at org.springframework.data.redis.core.RedisTemplate.execute(RedisTemplate.java:141)
at org.springframework.data.redis.cache.RedisCache.get(RedisCache.java:105)
at org.springframework.data.redis.cache.RedisCache.get(RedisCache.java:90)
at org.springframework.cache.interceptor.AbstractCacheInvoker.doGet(AbstractCacheInvoker.java:68)
at org.springframework.cache.interceptor.CacheAspectSupport.findInCaches(CacheAspectSupport.java:466)
at org.springframework.cache.interceptor.CacheAspectSupport.findCachedItem(CacheAspectSupport.java:432)
at org.springframework.cache.interceptor.CacheAspectSupport.execute(CacheAspectSupport.java:336)
at org.springframework.cache.interceptor.CacheAspectSupport.execute(CacheAspectSupport.java:302)
at org.springframework.cache.interceptor.CacheInterceptor.invoke(CacheInterceptor.java:61)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:208)
at com.sun.proxy.$Proxy93.getMasterAttributeValues(Unknown Source)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:302)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:190)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
at org.springframework.cache.interceptor.CacheInterceptor$1.invoke(CacheInterceptor.java:52)
at org.springframework.cache.interceptor.CacheAspectSupport.invokeOperation(CacheAspectSupport.java:320)
at org.springframework.cache.interceptor.CacheAspectSupport.execute(CacheAspectSupport.java:353)
at org.springframework.cache.interceptor.CacheAspectSupport.execute(CacheAspectSupport.java:302)
at org.springframework.cache.interceptor.CacheInterceptor.invoke(CacheInterceptor.java:61)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:208)
at com.sun.proxy.$Proxy95.search(Unknown Source)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:302)
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:190)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99)
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:281)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:208)
at com.sun.proxy.$Proxy96.search(Unknown Source)
at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:720)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99)
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:281)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:655)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:222)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:137)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:110)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:814)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:737)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:668)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
at org.springframework.test.web.servlet.TestDispatcherServlet.service(TestDispatcherServlet.java:65)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:770)
at org.springframework.mock.web.MockFilterChain$ServletFilterProxy.doFilter(MockFilterChain.java:167)
at org.springframework.mock.web.MockFilterChain.doFilter(MockFilterChain.java:134)
at org.springframework.test.web.servlet.MockMvc.perform(MockMvc.java:155)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
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:75)
at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86)
at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:254)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:89)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:193)
at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecuter.runTestClass(JUnitTestClassExecuter.java:114)
at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecuter.execute(JUnitTestClassExecuter.java:57)
at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassProcessor.processTestClass(JUnitTestClassProcessor.java:66)
at org.gradle.api.internal.tasks.testing.SuiteTestClassProcessor.processTestClass(SuiteTestClassProcessor.java:51)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:35)
at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
at org.gradle.internal.dispatch.ContextClassLoaderDispatch.dispatch(ContextClassLoaderDispatch.java:32)
at org.gradle.internal.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:93)
at com.sun.proxy.$Proxy3.processTestClass(Unknown Source)
at org.gradle.api.internal.tasks.testing.worker.TestWorker.processTestClass(TestWorker.java:109)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:35)
at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
at org.gradle.internal.remote.internal.hub.MessageHubBackedObjectConnection$DispatchWrapper.dispatch(MessageHubBackedObjectConnection.java:147)
at org.gradle.internal.remote.internal.hub.MessageHubBackedObjectConnection$DispatchWrapper.dispatch(MessageHubBackedObjectConnection.java:129)
at org.gradle.internal.remote.internal.hub.MessageHub$Handler.run(MessageHub.java:404)
at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:63)
at org.gradle.internal.concurrent.StoppableExecutorImpl$1.run(StoppableExecutorImpl.java:46)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)

Caused by: java.lang.NullPointerException
at com.lambdaworks.redis.protocol.CommandArgs.write(CommandArgs.java:121)
at com.lambdaworks.redis.protocol.CommandArgs.addKey(CommandArgs.java:54)
at com.lambdaworks.redis.BaseRedisCommandBuilder.createCommand(BaseRedisCommandBuilder.java:26)
at com.lambdaworks.redis.RedisCommandBuilder.get(RedisCommandBuilder.java:357)
at com.lambdaworks.redis.RedisAsyncConnectionImpl.get(RedisAsyncConnectionImpl.java:354)
at sun.reflect.GeneratedMethodAccessor354.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.lambdaworks.redis.FutureSyncInvocationHandler.handleInvocation(FutureSyncInvocationHandler.java:63)
at com.google.common.reflect.AbstractInvocationHandler.invoke(AbstractInvocationHandler.java:87)
at com.sun.proxy.$Proxy136.get(Unknown Source)
at org.springframework.data.redis.connection.lettuce.LettuceConnection.get(LettuceConnection.java:1173)
... 139 more

最佳答案

好的，这里有很多问题。它们都没有使用 Spring-Data-Redis 或连接客户端库。第一个属于我们如何生成 key 。如果您使用:

@Cacheable(....., key={#key1,#key2})

然后 Spring 会将生成的键视为 ArrayList。我无法使用默认的 org.springframework.data.redis.serializer.StringRedisSerializer 来处理它，因为它会由于 ArrayList != String 而遇到 ClassCastException。因此，我创建了 MultiKeySerializer 以在 ArrayList 获取一个实例以从中生成 key 时循环遍历 ArrayList。

public class MultiKeySerializer implements RedisSerializer<Object>{

private final Charset charset;

public MultiKeySerializer() {
    this(Charset.forName("UTF8"));
}

public MultiKeySerializer(Charset charset) {
    Assert.notNull(charset);
    this.charset = charset;
}

@Override
public byte[] serialize(Object t) throws SerializationException {

    if(t instanceof ArrayList){

        StringBuilder sb = new StringBuilder();
        ArrayList tList = (ArrayList) t;
        for(Object o: tList){
            sb.append(o == null ? null: o.toString()); 
        }

        String string = sb.toString();

        return (string == null ? null : string.getBytes(charset));
    }
    // return null - used to return null. Root cause.
    return t == null ? null : t.toString().getBytes(charset);
}

@Override
public String deserialize(byte[] bytes) throws SerializationException {

    return (bytes == null ? null : new String(bytes, charset));
}
}

问题是一些代码使用了@Cacheable 并且没有指定键属性。这导致 Spring 将其视为 SimpleKey，从而落入 key 生成逻辑。虽然 Spring-Data-Redis 不是罪魁祸首，但如果他们在键为 null 时给出更具描述性的异常就好了。

关于java - 带有@Cacheable的Spring Data Redis NullPointerException，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/44204918/