使用Kryo进行通用Java序列化/反序列化

Question

我试图使用和默认的序列化程序()序列化和反序列化自定义类的对象(例如,SomeClass具有默认的无参数构造函数)到byte[]数组.Kryo 2.19FieldSerializer

序列化似乎工作正常,但我在反序列化中得到各种异常,具体取决于实际的实现SomeClass.

代码看起来像这样:

SomeClass object = getObject(); // Create and populate a new object of SomeClass

Kryo kryo = new Kryo();
FieldSerializer<?> serializer = new FieldSerializer<SomeClass>(kryo, SomeClass.class);
kryo.register(SomeClass.class, serializer);

ByteArrayOutputStream stream = new ByteArrayOutputStream();
Output output = new Output(stream);

kryo.writeObject(output, object);

output.close(); // Also calls output.flush()

byte[] buffer = stream.toByteArray(); // Serialization done, get bytes

// Deserialize the serialized object.
object = kryo.readObject(new Input(new ByteArrayInputStream(buffer)), SomeClass.class);

我得到的例外情况的一个例子是:

Exception in thread "main" java.lang.IncompatibleClassChangeError: Found interface org.objectweb.asm.MethodVisitor, but class was expected
    at com.esotericsoftware.reflectasm.ConstructorAccess.insertConstructor(ConstructorAccess.java:89)
    at com.esotericsoftware.reflectasm.ConstructorAccess.get(ConstructorAccess.java:70)
    at com.esotericsoftware.kryo.Kryo.newInstantiator(Kryo.java:1009)
    at com.esotericsoftware.kryo.Kryo.newInstance(Kryo.java:1059)
    at com.esotericsoftware.kryo.serializers.FieldSerializer.create(FieldSerializer.java:228)
    at com.esotericsoftware.kryo.serializers.FieldSerializer.read(FieldSerializer.java:217)
    at com.esotericsoftware.kryo.Kryo.readObject(Kryo.java:629)

似乎参数化类型在反序列化方面存在问题.为了测试这个假设,这里是一个参数化的实现SomeClass和getObject():

class SomeClass<T extends Serializable>
{
    private final T[] elements;

    private final int first;
    private final int second;

    private SomeClass()
    {
        this.elements = null;
        this.first  = 0;
        this.second = 0;
    }

    private SomeClass(T[] elements, int first, int second)
    {
        this.elements = elements;
        this.first = first;
        this.second = second;
    }
}

SomeClass<?> getObject()
{
    String[] elements = new String[] {"This is a test", "one"};

    return new SomeClass<String>(elements, 1, 2);
}

这序列化很好,但反序列化会抛出以下异常(观察异常原因中如何报告字符串的第一个字母):

Exception in thread "main" com.esotericsoftware.kryo.KryoException: Unable to find class: his is a test
Serialization trace:
elements (net.cetas.parserserver.data.report.SourceDataReporter$SomeClass)
    at com.esotericsoftware.kryo.util.DefaultClassResolver.readName(DefaultClassResolver.java:132)
    at com.esotericsoftware.kryo.util.DefaultClassResolver.readClass(DefaultClassResolver.java:109)
    at com.esotericsoftware.kryo.Kryo.readClass(Kryo.java:613)
    at com.esotericsoftware.kryo.Kryo.readClassAndObject(Kryo.java:724)
    at com.esotericsoftware.kryo.serializers.DefaultArraySerializers$ObjectArraySerializer.read(DefaultArraySerializers.java:338)
    at com.esotericsoftware.kryo.serializers.DefaultArraySerializers$ObjectArraySerializer.read(DefaultArraySerializers.java:293)
    at com.esotericsoftware.kryo.Kryo.readObjectOrNull(Kryo.java:702)
    at com.esotericsoftware.kryo.serializers.FieldSerializer$ObjectField.read(FieldSerializer.java:521)
    at com.esotericsoftware.kryo.serializers.FieldSerializer.read(FieldSerializer.java:221)
    at com.esotericsoftware.kryo.Kryo.readObject(Kryo.java:629)

如果上面的类是在没有参数化的情况下实现的(即,elements数组声明为a String[]),则反序列化按预期工作.

有任何想法吗？

Answer 1

Exception in thread "main" java.lang.IncompatibleClassChangeError: Found interface org.objectweb.asm.MethodVisitor, but class was expected

请检查您在项目中使用的ASM版本.MethodVisitor是ASM中最高3.3的接口.在4.0版之后,这是一个类.

链接:

• http://asm.ow2.org/asm33/javadoc/user/org/objectweb/asm/MethodVisitor.html
• http://asm.ow2.org/asm40/javadoc/user/org/objectweb/asm/MethodVisitor.html