java.io.InvalidClassException: ; incompatible types for field 異常追蹤

java.io.InvalidClassException: <className>; incompatible types for field <fieldName> 異常追蹤 異常資訊

後台日誌中產生了如下異常資訊：

java.io.InvalidClassException: <className>; incompatible types for field <fieldName>        at java.io.ObjectStreamClass.matchFields(ObjectStreamClass.java:2299) ~[?:1.8.0_74]        at java.io.ObjectStreamClass.getReflector(ObjectStreamClass.java:2193) ~[?:1.8.0_74]        at java.io.ObjectStreamClass.initNonProxy(ObjectStreamClass.java:669) ~[?:1.8.0_74]        at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1623) ~[?:1.8.0_74]        at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1518) ~[?:1.8.0_74]        at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1774) ~[?:1.8.0_74]        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351) ~[?:1.8.0_74]        at java.io.ObjectInputStream.readArray(ObjectInputStream.java:1707) ~[?:1.8.0_74]        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1345) ~[?:1.8.0_74]        at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2000) ~[?:1.8.0_74]        at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1924) ~[?:1.8.0_74]        at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1801) ~[?:1.8.0_74]        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351) ~[?:1.8.0_74]        at java.io.ObjectInputStream.readObject(ObjectInputStream.java:371) ~[?:1.8.0_74]

涉及到OutputInputStream.readObject，因此猜測是對象還原序列化時，而產生的問題。 異常來源

 private static ObjectStreamField[] matchFields(ObjectStreamField[] fields,                                                   ObjectStreamClass localDesc)        throws InvalidClassException{  // ...           for (int j = 0; j < localFields.length; j++) {                ObjectStreamField lf = localFields[j];                if (f.getName().equals(lf.getName())) {                    if ((f.isPrimitive() || lf.isPrimitive()) &&                        f.getTypeCode() != lf.getTypeCode())                    {                        throw new InvalidClassException(localDesc.name,                            "incompatible types for field " + f.getName());                    }                    if (lf.getField() != null) {                        m = new ObjectStreamField(                            lf.getField(), lf.isUnshared(), false);                    } else {                        m = new ObjectStreamField(                            lf.getName(), lf.getSignature(), lf.isUnshared());                    }                }            }     // ... }

異常重現

import java.io.Serializable;public class Request implements Serializable {    private static final long serialVersionUID = 3663364724485038109L;    public Integer status;    public Integer addressStatus;    // setter getter}

序列化Request對象

public class Serialization {    public static void main(String[] args) throws IOException, ClassNotFoundException{        Request r1 = new Request();        r1.setAddressStatus(100);        r1.setStatus(200);        Request r2 = new Request();        r2.setAddressStatus(300);        r2.setStatus(400);        File file = new File("D:/MySQL/workspace/spring/resources/request.ser");        serializable(file, r1, r2);        Request[] rs = deserializable(file);        for (Request request : rs)            System.out.println(request.getAddressStatus() + " " + request.getStatus());    }    public static void serializable(File file, Request... requests) throws IOException {        ObjectOutputStream stream = new ObjectOutputStream(new FileOutputStream(file));        if (requests != null)            stream.writeObject(requests);        stream.close();    }    public static Request[] deserializable(File file) throws IOException, ClassNotFoundException {        ObjectInputStream stream = new ObjectInputStream(new FileInputStream(file));        Request[] requests = (Request[])stream.readObject();        stream.close();        return requests;    }}

修改Request範圍類型

import java.io.Serializable;public class Request implements Serializable {    private static final long serialVersionUID = 3663364724485038109L;    public int status;    public int addressStatus;    // setter getter}

還原序列化對象

public class Serialization {    public static void main(String[] args) throws IOException, ClassNotFoundException{        Request r1 = new Request();        r1.setAddressStatus(100);        r1.setStatus(200);        Request r2 = new Request();        r2.setAddressStatus(300);        r2.setStatus(400);        File file = new File("D:/MySQL/workspace/spring/resources/request.ser");        Request[] rs = deserializable(file);        for (Request request : rs)            System.out.println(request.getAddressStatus() + " " + request.getStatus());    }    public static void serializable(File file, Request... requests) throws IOException {        ObjectOutputStream stream = new ObjectOutputStream(new FileOutputStream(file));        if (requests != null)            stream.writeObject(requests);        stream.close();    }    public static Request[] deserializable(File file) throws IOException, ClassNotFoundException {        ObjectInputStream stream = new ObjectInputStream(new FileInputStream(file));        Request[] requests = (Request[])stream.readObject();        stream.close();        return requests;    }}

將會拋出如下異常

Exception in thread "main" java.io.InvalidClassException: com.spring.domain.Request; incompatible types for field addressStatus    at java.io.ObjectStreamClass.matchFields(ObjectStreamClass.java:2399)    at java.io.ObjectStreamClass.getReflector(ObjectStreamClass.java:2293)    at java.io.ObjectStreamClass.initNonProxy(ObjectStreamClass.java:741)    at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1876)    at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1745)    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2033)    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1567)    at java.io.ObjectInputStream.readArray(ObjectInputStream.java:1966)    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1561)    at java.io.ObjectInputStream.readObject(ObjectInputStream.java:427)    at com.spring.domain.Serialization.deserializable(Serialization.java:38)    at com.spring.domain.Serialization.main(Serialization.java:24)

調試分析,可知還原序列化類型為int和對象的序列化類別型為Integer, 因此產生異常。

總結

項目中使用了Spring httpinvoker 遠程服務。用戶端與服務端使用一套服務介面，而介面的具體實現是在服務端。

用戶端調用遠程方法時，會序列化要調用的(介面)方法和參數，發送到服務端。

服務端會根據請求還原序列化還原，調用具體方法擷取結果，並將結果序列化發給用戶端。

用戶端接收響應，將服務端結果還原序列化還原。

而如果用戶端與服務端代碼的版本不一致，就會產生該異常。