Dubbo序列化問題排查

h1. 現象

為一個dubbbo介面新增了一個方法：

{code}DomainObject<String> testSer();實現：@Override    public DomainObject<String> testSer() {        DomainObject<String> result = new DomainObject<String>();        result.setAge(10);        result.setName("test");        result.add("DomainObject1");        return result;    }{code}

傳回值定義如下：

{code}public class DomainObject<E> extends ArrayList<E> {    private static final long serialVersionUID = -7393642276493435828L;    private String name;    private int    age;}{code}

遠程調用：

{code}DomainObject<String> result = voucherInfoQueryService.testSer();System.out.println(result.getAge());System.out.println(result.getName());System.out.println(result.get(0));{code}

輸出結果：丟失了age和name兩個屬性的值，而 list內部的值還是存在的

{code}0nullDomainObject1{code}

h1. 問題排查h4. 使用java內建序列化執行序列化和還原序列化， 不會出現屬性丟失的問題，懷疑dubbo序列化有特殊處理h4. dubbo 預設用的序列化協議是hessian2，查看代碼

序列化時代碼如下:

{code}public void writeObject(Object object)    throws IOException  {    if (object == null) {      writeNull();      return;    }    Serializer serializer;    ##尋找對應的serializer    serializer = findSerializerFactory().getSerializer(object.getClass());    ##序列化    serializer.writeObject(object, this);  }{code}

尋找serializer：由代碼可知，上面的DomainObject對應的serializer是CollectionSerializer

{code}public Serializer getSerializer(Class cl)    throws HessianProtocolException  {  ...   else if (Collection.class.isAssignableFrom(cl)) {      if (_collectionSerializer == null) {_collectionSerializer = new CollectionSerializer();   ...      }{code}

CollectionSerializer.writeObject

{code}public void writeObject(Object obj, AbstractHessianOutput out)    throws IOException  {    ...    Iterator iter = list.iterator();    while (iter.hasNext()) {      Object value = iter.next();      out.writeObject(value);    }    ...  }{code}

所以，屬性丟失。