Java中的任何模块是否等同于python的搁置模块?我需要这个来实现像分类数据访问这样的字典.类字典分类数据访问是一种以持久的访问数据库格式保存Python对象的强大方法.我需要一些东西用于相同的目的但是用Java.
解决方法:
我也需要这个,所以我写了一个.有点晚了,但也许它会有所帮助.
它没有实现close()方法,只是使用sync(),因为它只在实际写入时保持文件打开.
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.HashMap;
public class Shelf extends HashMap<String, Object> {
private static final long serialVersionUID = 7127639025670585367L;
private final File file;
public static Shelf open(File file) {
Shelf shelf = null;
try {
if (file.exists()) {
final FileInputStream fis = new FileInputStream(file);
ObjectInputStream ois = new ObjectInputStream(fis);
shelf = (Shelf) ois.readObject();
ois.close();
fis.close();
} else {
shelf = new Shelf(file);
shelf.sync();
}
} catch (Exception e) {
// TODO: handle errors
}
return shelf;
}
// Shelf objects can only be created or opened by the Shelf.open method
private Shelf(File file) {
this.file = file;
sync();
}
public void sync() {
try {
final FileOutputStream fos = new FileOutputStream(file);
ObjectOutputStream oos = new ObjectOutputStream(fos);
oos.writeObject(this);
oos.close();
fos.close();
} catch (Exception e) {
// TODO: handle errors
}
}
// Simple Test Case
public static void main(String[] args) {
Shelf shelf = Shelf.open(new File("test.obj"));
if (shelf.containsKey("test")) {
System.out.println(shelf.get("test"));
} else {
System.out.println("Creating test string. Run the program again.");
shelf.put("test", "Hello Shelf!");
shelf.sync();
}
}
}