java反序列化的试验

试验目的：哪些情况会导致java反序列化失败。

 

持久化到本地

 

public class Test {

	private static String file = "/serialFile.txt";
	
	public static void main(String[] args)throws Exception {
		
		write();
		//read();
		
	}
	
	static void write() throws Exception{
		FileOutputStream os = new FileOutputStream(file);
		ObjectOutputStream oos = new ObjectOutputStream(os);
		Student s = new Student();
		s.setAge(20);
		s.setName("test");
		s.setState(State.TEST);
		oos.writeObject(s);
		oos.close();
	}
	
	static void read() throws Exception{
		FileInputStream is = new FileInputStream(file);
		ObjectInputStream ois = new ObjectInputStream(is);
		Student s = (Student)ois.readObject();
		System.out.println(s);
	}
}

class Student implements Serializable {
	
	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;

	State state;
	
	
	
	String name;
	
	String id;
	
	int age;

	public void setState(State state) {
		this.state = state;
	}

	public void setName(String name) {
		this.name = name;
	}

	
	
	public void setAge(int age) {
		this.age = age;
	}
	
	public String getId() {
		return id;
	}

	public void setId(String id) {
		this.id = id;
	}

	public String toString(){
		StringBuffer str = new StringBuffer();
		str.append("state:").append(state != null ? state.getValue() : "error").append(" ");
		str.append("name:" + name).append(" ");
		str.append("age:" + age).append(" ");
		str.append("id:" + id);
		return str.toString();
	}
}


public enum State {

	COMMON(1),TEST(2);
	
	private int value;
	
	private State(int value){
		this.value = value;
	}

	public int getValue() {
		return value;
	}

	public void setValue(int value) {
		this.value = value;
	}
	
	
}

 

 

1.枚举类型实例删除,反序列化会有问题

  //将 Test实例删除
  public enum State {

	COMMON(1);
	
	private int value;
	
	private State(int value){
		this.value = value;
	}

	public int getValue() {
		return value;
	}

	public void setValue(int value) {
		this.value = value;
	}
	
	
 }

 

Exception in thread "main" java.io.InvalidObjectException: enum constant TEST does not exist in class com.my.test.serializable.State
	at java.io.ObjectInputStream.readEnum(ObjectInputStream.java:1704)
	at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1326)
	at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1947)
	at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1871)
	at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1753)
	at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1329)
	at java.io.ObjectInputStream.readObject(ObjectInputStream.java:351)
	at com.my.test.serializable.Test.read(Test.java:34)
	at com.my.test.serializable.Test.main(Test.java:16)
Caused by: java.lang.IllegalArgumentException: No enum const class com.my.test.serializable.State.TEST
	at java.lang.Enum.valueOf(Enum.java:196)
	at java.io.ObjectInputStream.readEnum(ObjectInputStream.java:1702)
	... 8 more

 

 

2.减少一个属性,和方法,执行read() ,不会有问题

   减少以下代码

  

    String name;
	
public void setName(String name) {
     this.name = name;
}

 

 

3.增加属性和方法,执行read(),不会有问题

 

                //增加
	String id;
	
	
	//增加
	public String getId() {
		return id;
	}
	
	//增加
	public void setId(String id) {
		this.id = id;
	}

 

4.将private static final long serialVersionUID = 1L;变成2,执行read()

 

Exception in thread "main" java.io.InvalidClassException: com.my.test.serializable.Student; 
	local class incompatible: stream classdesc serialVersionUID = 1, local class serialVersionUID = 2
	at java.io.ObjectStreamClass.initNonProxy(ObjectStreamClass.java:562)
	at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1583)
	at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1496)
	at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1732)
	at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1329)
	at java.io.ObjectInputStream.readObject(ObjectInputStream.java:351)
	at com.my.test.serializable.Test.read(Test.java:34)
	at com.my.test.serializable.Test.main(Test.java:16)

 

 

部分结论：

 

1.反序列化时如果是减少或增加属性（包括枚举），方法，不会有问题

2.如果要反序列化枚举实例时，程序端有该枚举类型但没有该实例，则抛错。

3.如果反序列化时,程序端原枚举类型增加了新的实例且原实例存在,不会抛错.

4.序列化版本号不对，抛错。