是否可以以易于阅读的格式将对象发送到文件？

Question

I am working on a project for my advanced Java class, and the assignment says he wants us to send an object to a file, which is easy enough, but that he also wants the file to be human readable and editable. I sent him an e-mail 3 days ago and he hasn't responded, so I am kind of stuck between a rock and hard place since the project is due in 3 days.

So would any of you clever programmers be able to fill me in on the secret that apparently I am left out of.

How do you send an object to a file that reads like English?

I want to have the ability to both read and write a to-do item to a file. I see our application looking like:

1. When it first starts, the program asks the user if there is a file containing to-do items. If so, the user will name the file, the program will read it in and continue.
2. When the user decides to exit, the program will prompt the user - to ask if the to-do items should be saved to a file - if so, the user will name the file and the program will write them out in such a fashion that it can read them in again.

I want these file to be human readable (and editable). No binary data. No counting. My advice to you would be to have a method somewhere that looked like:

 public ToDoItem getToDoItem(FileInputStream fis) { // ... } 

and

 public void writeToDoItem(FileOutputStream fos) { // ... } 

Answer 1

Think of your serialization model. The ObjectOutputStream might write bytes, but is there another way you could represent the object and write it through some other output stream that writes human-readable text?

Answer 2

This is going to depend on the type of object you have. You will have to tailor it to a particular type of data.

For example, if you have an Object

String title;
List<Integer> ids;

then you could save it as JSON

{
   title: 'aaaa',
   ids: [ 1,2,3,4,5 ]
}

which is equivalent, but much more readable than a binary ObjectOutputStream.

Again, this won't work for all kinds of data.

There is an XML-based bean serialization, too, which also works with almost all data, but I would not call that human-readable.

Answer 3

You can have a try with JAXB.(Java Architecture for XML Binding) It can send a JAXB styled object to a xml file. But you should define a XML Schema file at first. For more:http://jaxb.java.net/tutorial/

Answer 4

Think how you would represent an object on paper in such a way that it could be reconstructed unambiguously. You'd probably list the class name, then you'd list each field name and its current value. If the field was a primitive, the value would be just the primitive value. If it was a reference type, you'd represent the object recursively using this procedure. If it was an array, you'd list each element value.

There are various standard ways of formatting such a representation (XML and JSON to name a couple). The key is to make it a text-only representation so it is human-readable.

Answer 5

The human readable that you desire could be XML or JSON . My answer How to create object tree from xsd in Java?

might help in giving you pointers to the approach you can follow to achieve what you want.