Spring Boot + Infinispan 嵌入式 - 當要緩存的對象被修改時如何防止 ClassCastException？

Question

我有一個帶有 Spring Boot 2.5.5 和嵌入式 Infinispan 12.1.7 的 Web 應用程序。

我有一個帶有端點的控制器，可以通過 ID 獲取 Person 對象：

@RestController
public class PersonController {

    private final PersonService service;

    public PersonController(PersonService service) {
        this.service = service;
    }

    @GetMapping("/person/{id}")
    public ResponseEntity<Person> getPerson(@PathVariable("id") String id) {
        Person person = this.service.getPerson(id);
        return ResponseEntity.ok(person);
    }
}

以下是在getPerson方法上使用@Cacheable注釋的PersonService實現：

public interface PersonService {

    Person getPerson(String id);
}

@Service
public class PersonServiceImpl implements PersonService {

    private static final Logger LOG = LoggerFactory.getLogger(PersonServiceImpl.class);

    @Override
    @Cacheable("person")
    public Person getPerson(String id) {
        LOG.info("Get Person by ID {}", id);

        Person person = new Person();
        person.setId(id);
        person.setFirstName("John");
        person.setLastName("Doe");
        person.setAge(35);
        person.setGender(Gender.MALE);
        person.setExtra("extra value");

        return person;
    }
}

這是 Person 類：

public class Person implements Serializable {

    private static final long serialVersionUID = 1L;

    private String id;
    private String firstName;
    private String lastName;
    private Integer age;
    private Gender gender;
    private String extra;

    /* Getters / Setters */
    ...
}

我將 infinispan 配置為使用基於文件系統的緩存存儲：

<?xml version="1.0" encoding="UTF-8"?>
<infinispan xmlns="urn:infinispan:config:12.1"
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xsi:schemaLocation="urn:infinispan:config:12.1 https://infinispan.org/schemas/infinispan-config-12.1.xsd">
    <cache-container default-cache="default">

        <serialization marshaller="org.infinispan.commons.marshall.JavaSerializationMarshaller">
            <allow-list>
                <regex>com.example.*</regex>
            </allow-list>
        </serialization>

        <local-cache-configuration name="mirrorFile">
            <persistence passivation="false">
                <file-store path="${infinispan.disk.store.dir}"
                            shared="false"
                            preload="false"
                            purge="false"
                            segmented="false">
                </file-store>
            </persistence>
        </local-cache-configuration>

        <local-cache name="person" statistics="true" configuration="mirrorFile">
            <memory max-count="500"/>
            <expiration lifespan="86400000"/>
        </local-cache>
    </cache-container>
</infinispan>

我請求端點獲取 ID 為“1”的人：http://localhost:8090/assets-webapp/person/1
第一次調用PersonService.getPerson(String)並緩存結果。
我再次請求端點獲取 ID 為“1”的人，並在緩存中檢索結果。

我通過使用 getter/setter 刪除extra字段來更新Person對象，並添加一個extra2字段：

public class Person implements Serializable {

    private static final long serialVersionUID = 1L;

    private String id;
    private String firstName;
    private String lastName;
    private Integer age;
    private Gender gender;
    private String extra2;

    ...

    public String getExtra2() {
        return extra2;
    }

    public void setExtra2(String extra2) {
        this.extra2 = extra2;
    }
}

我再次請求端點獲取 ID 為“1”的人，但拋出了ClassCastException ：

java.lang.ClassCastException: com.example.controller.Person cannot be cast to com.example.controller.Person] with root cause java.lang.ClassCastException: com.example.controller.Person cannot be cast to com.example.controller.Person
    at com.example.controller.PersonServiceImpl$$EnhancerBySpringCGLIB$$ec42b86.getPerson(<generated>) ~[classes/:?]
    at com.example.controller.PersonController.getPerson(PersonController.java:19) ~[classes/:?]

我通過刪除extra2字段並添加extra字段來回滾 Person 對象修改。
我再次請求端點獲取 ID 為“1”的人，但始終拋出ClassCastException

infinispan 使用的編組器是JavaSerializationMarshaller 。

我猜如果類已經重新編譯，java 序列化不允許對緩存的數據進行解組。

但我想知道如何避免這種情況，尤其是能夠在訪問緩存數據時管理類的更新（添加/刪除字段）而不會出現異常。

有沒有人有辦法解決嗎？

Answer 1

最好的選擇是將緩存編碼更改為application/x-protostream並使用 ProtoStream 庫序列化您的對象。

<local-cache-configuration name="mirrorFile">
   <encoding>
      <key media-type="application/x-protostream"/>
      <value media-type="application/x-protostream"/>
   </encoding>
</local-cache>

Infinispan 緩存默認將實際的 Java 對象保存在內存中，而不對其進行序列化。 配置的編組器僅用於將條目寫入磁盤。

當您修改類時，Spring 可能會在新的類加載器中創建一個同名的新類。 但是緩存中的對象仍然使用舊類加載器中的類，因此它們與新類不兼容。

配置除application/x-java-object之外的編碼媒體類型會告訴 Infinispan 序列化保留在內存中的對象。

您還可以將緩存編碼更改為application/x-java-serialized-object ，以便您的對象使用JavaSerializationMarshaller存儲在內存中，它已經用於在磁盤上存儲對象。 但是使用 Java 序列化保持與舊版本的兼容性需要大量工作，並且需要提前計划：您需要一個serialVersionUUID字段，可能是一個版本字段，以及一個可以讀取舊格式的readExternal()實現。 使用 ProtoStream，因為它基於 Protobuf 模式，您可以輕松添加新（可選）字段並忽略不再使用的字段，只要您不更改或重用字段編號。

Answer 2

我最終創建了自己的 Marshaller，在 JSON 中進行序列化/反序列化，靈感來自以下類： GenericJackson2JsonRedisSerializer.java

public class JsonMarshaller extends AbstractMarshaller {

    private static final byte[] EMPTY_ARRAY = new byte[0];

    private final ObjectMapper objectMapper;

    public JsonMarshaller() {
        this.objectMapper = objectMapper();
    }

    private ObjectMapper objectMapper() {
        ObjectMapper objectMapper = new ObjectMapper();

        objectMapper.enable(JsonGenerator.Feature.IGNORE_UNKNOWN);
        objectMapper.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);
        objectMapper.enable(DeserializationFeature.ACCEPT_SINGLE_VALUE_AS_ARRAY);
        objectMapper.activateDefaultTyping(objectMapper.getPolymorphicTypeValidator(), ObjectMapper.DefaultTyping.NON_FINAL, JsonTypeInfo.As.PROPERTY);

        // Serialize/Deserialize objects from any fields or creators (constructors and (static) factory methods). Ignore getters/setters.
        objectMapper.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.NONE);
        objectMapper.setVisibility(PropertyAccessor.CREATOR, JsonAutoDetect.Visibility.ANY);
        objectMapper.setVisibility(PropertyAccessor.FIELD, JsonAutoDetect.Visibility.ANY);

        // Register support of other new Java 8 datatypes outside of date/time: most notably Optional, OptionalLong, OptionalDouble
        objectMapper.registerModule(new Jdk8Module());

        // Register support for Java 8 date/time types (specified in JSR-310 specification)
        objectMapper.registerModule(new JavaTimeModule());

        // simply setting {@code mapper.disable(SerializationFeature.FAIL_ON_EMPTY_BEANS)} does not help here since we need
        // the type hint embedded for deserialization using the default typing feature.
        objectMapper.registerModule(new SimpleModule("NullValue Module").addSerializer(new NullValueSerializer(null)));

        objectMapper.registerModule(
                new SimpleModule("SimpleKey Module")
                        .addSerializer(new SimpleKeySerializer())
                        .addDeserializer(SimpleKey.class, new SimpleKeyDeserializer(objectMapper))
        );

        return objectMapper;
    }

    @Override
    protected ByteBuffer objectToBuffer(Object o, int estimatedSize) throws IOException, InterruptedException {
        return ByteBufferImpl.create(objectToBytes(o));
    }

    private byte[] objectToBytes(Object o) throws JsonProcessingException {
        if (o == null) {
            return EMPTY_ARRAY;
        }
        return objectMapper.writeValueAsBytes(o);
    }

    @Override
    public Object objectFromByteBuffer(byte[] buf, int offset, int length) throws IOException, ClassNotFoundException {
        if (isEmpty(buf)) {
            return null;
        }
        return objectMapper.readValue(buf, Object.class);
    }

    @Override
    public boolean isMarshallable(Object o) throws Exception {
        return true;
    }

    @Override
    public MediaType mediaType() {
        return MediaType.APPLICATION_JSON;
    }

    private static boolean isEmpty(byte[] data) {
        return (data == null || data.length == 0);
    }

    /**
     * {@link StdSerializer} adding class information required by default typing. This allows de-/serialization of {@link NullValue}.
     */
    private static class NullValueSerializer extends StdSerializer<NullValue> {

        private static final long serialVersionUID = 1999052150548658808L;
        private final String classIdentifier;

        /**
         * @param classIdentifier can be {@literal null} and will be defaulted to {@code @class}.
         */
        NullValueSerializer(String classIdentifier) {

            super(NullValue.class);
            this.classIdentifier = StringUtils.isNotBlank(classIdentifier) ? classIdentifier : "@class";
        }

        @Override
        public void serialize(NullValue value, JsonGenerator jgen, SerializerProvider provider) throws IOException {
            jgen.writeStartObject();
            jgen.writeStringField(classIdentifier, NullValue.class.getName());
            jgen.writeEndObject();
        }
    }
}

SimpleKey 對象的序列化器/反序列化器：

public class SimpleKeySerializer extends StdSerializer<SimpleKey> {

    private static final Logger LOG = LoggerFactory.getLogger(SimpleKeySerializer.class);

    protected SimpleKeySerializer() {
        super(SimpleKey.class);
    }

    @Override
    public void serialize(SimpleKey simpleKey, JsonGenerator gen, SerializerProvider provider) throws IOException {
        gen.writeStartObject();
        serializeFields(simpleKey, gen, provider);
        gen.writeEndObject();
    }

    @Override
    public void serializeWithType(SimpleKey value, JsonGenerator gen, SerializerProvider provider, TypeSerializer typeSer) throws IOException {
        WritableTypeId typeId = typeSer.typeId(value, JsonToken.START_OBJECT);
        typeSer.writeTypePrefix(gen, typeId);
        serializeFields(value, gen, provider);
        typeSer.writeTypeSuffix(gen, typeId);

    }

    private void serializeFields(SimpleKey simpleKey, JsonGenerator gen, SerializerProvider provider) {
        try {
            Object[] params = (Object[]) FieldUtils.readField(simpleKey, "params", true);
            gen.writeArrayFieldStart("params");
            gen.writeObject(params);
            gen.writeEndArray();
        } catch (Exception e) {
            LOG.warn("Could not read 'params' field from SimpleKey {}: {}", simpleKey, e.getMessage(), e);
        }
    }
}

public class SimpleKeyDeserializer extends StdDeserializer<SimpleKey> {

    private final ObjectMapper objectMapper;

    public SimpleKeyDeserializer(ObjectMapper objectMapper) {
        super(SimpleKey.class);
        this.objectMapper = objectMapper;
    }

    @Override
    public SimpleKey deserialize(JsonParser jp, DeserializationContext ctxt) throws IOException, JsonProcessingException {
        List<Object> params = new ArrayList<>();
        TreeNode treeNode = jp.getCodec().readTree(jp);
        TreeNode paramsNode = treeNode.get("params");
        if (paramsNode.isArray()) {
            for (JsonNode paramNode : (ArrayNode) paramsNode) {
                Object[] values = this.objectMapper.treeToValue(paramNode, Object[].class);
                params.addAll(Arrays.asList(values));
            }
        }
        return new SimpleKey(params.toArray());
    }

}

我將 infinispan 配置如下：

<?xml version="1.0" encoding="UTF-8"?>
<infinispan xmlns="urn:infinispan:config:12.1"
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xsi:schemaLocation="urn:infinispan:config:12.1 https://infinispan.org/schemas/infinispan-config-12.1.xsd">
    <cache-container default-cache="default">

        <serialization marshaller="com.example.JsonMarshaller">
            <allow-list>
                <regex>com.example.*</regex>
            </allow-list>
        </serialization>

        <local-cache-configuration name="mirrorFile">
            <persistence passivation="false">
                <file-store path="${infinispan.disk.store.dir}"
                            shared="false"
                            preload="false"
                            purge="false"
                            segmented="false">
                </file-store>
            </persistence>
        </local-cache-configuration>

        <local-cache name="person" statistics="true" configuration="mirrorFile">
            <memory max-count="500"/>
            <expiration lifespan="86400000"/>
        </local-cache>
    </cache-container>
</infinispan>