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加载序列化对象

serialization java

user3639557 · 技术社区 · 6 年前

Person )在另一个班级里工作:

public class Dummy{
    ...
    public static void main(String args[])
    {
        ...
        Person father = null;
        try {
            FileInputStream load = new FileInputStream(saved_file);
            ObjectInputStream in = new ObjectInputStream(load);
            indiv = (Person) in.readObject();
            in.close();
            load.close();
        } catch (...) { ... }
     }
 }

但是,为了保持整洁,有没有可能将它作为函数移到Person类中呢?例如,要执行以下操作:

public class Person implements Serializable {

    private boolean isOrphan = false;
    private Person parent;
    ...

    public void load(File saved_file) {
        try {
            FileInputStream load = new FileInputStream(saved_file);
            ObjectInputStream in = new ObjectInputStream(load);
            this = (Person) in.readObject(); // Error: cannot assign a value to final variabl this
            in.close();
            load.close();
         } catch (...) { ... }
     }
}

在另一节课上就叫这个:

public class Dummy{
    ...
    public static void main(String args[])
    {
        ...
        Person father = null;
        father.load(saved_file);
    }
}

1 回复 | 直到 6 年前

Dici gla3dr 6 年前

NullPointerException 因为你在调用一个方法 null .

使方法成为静态的,并使其返回反序列化的实例。一般来说, this

public static Person load(File saved_file) {
    try (FileInputStream load = new FileInputStream(saved_file);
         ObjectInputStream in = new ObjectInputStream(load)) {
        return (Person) in.readObject();
     } catch (...) { ... }
 }

public class Dummy {
    public static void main(String args[]) {
        Person father = Person.load(saved_file);
    }
}

附言:我还加了一句而不是显式的 close()