我正在探索可外部化的接口。当我在序列化文件中写的属性比我读的更多时，我发现了一个奇怪的行为。下面是我的员工类。
public class Employee implements Externalizable {
private int id;
private String name;
private Boolean isTempEmp;
public Employee(int id, String name, Boolean isTempEmp) {
super();
this.id = id;
this.name = name;
this.isTempEmp = isTempEmp;
}
@Override
public String toString() {
return "Employee [id=" + id + ", name=" + name + ", isTempEmp=" + isTempEmp + "]";
}
@Override
public void writeExternal(ObjectOutput out) throws IOException {
out.writeInt(id);
out.writeUTF(name);
out.writeBoolean(isTempEmp);
}
@Override
public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
this.id=in.readInt();
this.name=in.readUTF();
//this.isTempEmp=in.readBoolean();
}
}
下面是我的类，用于将文件中的员工对象外部化并从文件中读取
public class ExternalizeTest2 {
public static void main(String[] args) {
Employee emp1=new Employee(1, "Swet", true);
Employee emp4=new Employee(2, "Varun", true);
try(OutputStream os=new FileOutputStream("Employee.txt");
ObjectOutputStream oos=new ObjectOutputStream(os);) {
emp1.writeExternal(oos);
emp4.writeExternal(oos);
}catch (Exception e) {
e.printStackTrace();
}
Employee emp2=new Employee(3, "Test1", false);
Employee emp3=new Employee(4, "Test2", false);
try(InputStream is=new FileInputStream("Employee.txt");
ObjectInputStream ois=new ObjectInputStream(is);) {
emp2.readExternal(ois);
emp3.readExternal(ois);
}catch (Exception e) {
e.printStackTrace();
}
System.out.println("After externalization: \n"+emp2.toString());
System.out.println(emp3.toString());
}
}
下面是我得到的输出：
java.io.EOFException
at java.io.ObjectInputStream$BlockDataInputStream.readByte(Unknown Source)
at java.io.ObjectInputStream$BlockDataInputStream.readUTFChar(Unknown Source)
at java.io.ObjectInputStream$BlockDataInputStream.readUTFBody(Unknown Source)
at java.io.ObjectInputStream$BlockDataInputStream.readUTF(Unknown Source)
at java.io.ObjectInputStream.readUTF(Unknown Source)
at serialization.externalize.Employee.readExternal(Employee.java:40)
at serialization.externalize.ExternalizeTest2.main(ExternalizeTest2.java:32)
After externalization:
Employee [id=1, name=Swet, isTempEmp=false]
Employee [id=16777216, name=Test2, isTempEmp=false]
不确定分配给 emp3 的 id 是 16777216。