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我有一個類似的問題發佈，它變得混亂，這將是更容易遵循。在Runner（）中的部分是/ 註釋掉了 /。你取消註釋，運行程序一次，檢查你的控制檯打印出來。然後/ 再次註釋掉 /並再次運行該程序，您會注意到subCodebook = {}正在返回一個空白/空值;這是我的問題，爲什麼這返回null。問題保存和加載到/從Java文件
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
import java.io.Serializable;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
public class Runner {
Map<Integer, String> decodebook = new HashMap<Integer, String>();
// List<Integer> numbers = new LinkedList<Integer>();
Map<String, List<Integer>> codebook = new HashMap<String, List<Integer>>();
Map<String, List<Integer>> subcodebook = new HashMap<String, List<Integer>>();
List<Integer> numbers = new LinkedList<Integer>();
List<Integer> otherNumbers = new LinkedList<Integer>();
public static void main(String[] args) throws IOException {
new Runner();
}
public Runner() throws IOException {
/*numbers.add(6);
numbers.add(156);
numbers.add(363);
numbers.add(336);
numbers.add(26);
numbers.add(61);
otherNumbers.add(68);
otherNumbers.add(78);
otherNumbers.add(28);
otherNumbers.add(668);
otherNumbers.add(618);
otherNumbers.add(686);
otherNumbers.add(682);
subcodebook.put("tony", numbers.subList(0, 2));
subcodebook.put("alf", numbers.subList(3, 5));
codebook.put("alf", numbers);
codebook.put("tony", otherNumbers);
decodebook.put(7898, "alf");
decodebook.put(87576, "tony");
saveStuff();*/
loadBooks();
System.out.println(" codebook" + codebook);
System.out.println(" decodebook" + decodebook);
System.out.println(" subCodebook" + subcodebook);
}
public void loadBooks() throws IOException {
loadCodeBook("CodeBook");
//System.out.println(codebook);
loadsubCodeBook("subCodeBook");
loadDeCodeBook("DecodeBook");
// System.out.println(codebook);
//System.out.println(decodebook);
}
public Map<String, List<Integer>> loadCodeBook(String filePath)
throws IOException {
HashMap<String, List<Integer>> codebook = null;
InputStream is = null;
try {
is = new ObjectInputStream(new FileInputStream(filePath));
codebook = (HashMap<String, List<Integer>>) ((ObjectInputStream) is)
.readObject();
} catch (Exception ex) {
} finally {
is.close();
}
return this.codebook = codebook;
}
public Map<String, List<Integer>> loadsubCodeBook(String filePath)
throws IOException {
HashMap<String, List<Integer>> subcodebook = null;
InputStream is = null;
try {
is = new ObjectInputStream(new FileInputStream(filePath));
subcodebook = (HashMap<String, List<Integer>>) ((ObjectInputStream) is)
.readObject();
} catch (Exception ex) {
} finally {
is.close();
}
return this.subcodebook = subcodebook;
}
public Map<Integer, String> loadDeCodeBook(String filePath)
throws IOException {
HashMap<Integer, String> decodebook = null;
InputStream is = null;
try {
is = new ObjectInputStream(new FileInputStream(filePath));
decodebook = (HashMap<Integer, String>) ((ObjectInputStream) is)
.readObject();
} catch (Exception ex) {
} finally {
is.close();
}
return this.decodebook = decodebook;
}
public void saveStuff() {
try {
saveCodeBook(codebook, "CodeBook");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
saveDecodeBook(decodebook, "DecodeBook");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
savesubCodeBook(subcodebook, "subcodeBook");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void saveCodeBook(Map<String, List<Integer>> obj, String filePath)
throws IOException {
OutputStream os = null;
try {
os = new ObjectOutputStream(new FileOutputStream(filePath));
((ObjectOutputStream) os).writeObject(obj);
} catch (Exception ex) {
} finally {
os.close();
}
}
public void savesubCodeBook(Map<String, List<Integer>> obj, String filePath)
throws IOException {
OutputStream os = null;
try {
os = new ObjectOutputStream(new FileOutputStream(filePath));
((ObjectOutputStream) os).writeObject(obj);
} catch (Exception ex) {
} finally {
os.close();
}
}
public void saveDecodeBook(Map<Integer, String> obj, String filePath)
throws IOException {
OutputStream os = null;
try {
os = new ObjectOutputStream(new FileOutputStream(filePath));
((ObjectOutputStream) os).writeObject(obj);
} catch (Exception ex) {
} finally {
os.close();
}
}
}
您沒有保存並加載subCodebook。 – drkunibar
@drkunibar我改變了上面的代碼，並如預期的那樣，它現在爲空，我想知道爲什麼它沒有返回null。所以現在打印出來了。 codebook {alf = [6,156,363,336,26,61]，tony = [68,78,28,668,618,686,682]} decodebook {87576 = tony，7898 = alf} subCodebooknull – user3459475
好的我明白了。看看我的回答 – drkunibar