我有几个对象,它们根据用户输入分配属性。然后,我将这些对象存储在 vector 中,然后将该 vector 写入文件,但在反序列化存储的 vector 时,仅读取第一个对象。这是我到目前为止的代码:
public Vector<Cases> registerCase() {
Vector<Cases> casesVector = new Vector<Cases>(10, 2);
Scanner myCase = new Scanner(System.in);
Scanner userChoice = new Scanner(System.in);
System.out.println("HOW MANY CASES DO YOU WANT TO REGISTER?");
int count = userChoice.nextInt();
for (int i = 0; i < count; i++) {
Cases newCase = new Cases();
System.out.println("Enter the case name: ");
newCase.caseName = myCase.nextLine();
System.out.println("Enter the client's name: ");
newCase.client = myCase.nextLine();
System.out.println("Enter the case type: ");
newCase.caseType = myCase.nextLine();
if((newCase.caseType.equals("Major")) || newCase.caseType.equals("major")){
newCase.closedCaseRevenue = majorCasePrice;
}else {
newCase.closedCaseRevenue = (int) (0.75 * majorCasePrice);
}
casesVector.add(newCase);
}
try{
// Open a file to write to, named SavedCases.sav.
FileOutputStream saveFile = new FileOutputStream("SavedCases.sav", true);
ObjectOutputStream save = new ObjectOutputStream(saveFile);
save.writeObject(casesVector);
save.close();
}
catch(Exception exc){
exc.printStackTrace();
}
Vector<Cases> comVector = new Vector<Cases>();
try{
FileInputStream saveFile = new FileInputStream("SavedCases.sav");
ObjectInputStream save = new ObjectInputStream(saveFile);
comVector = (Vector<Cases>) save.readObject();
System.out.println("The size of the vector is: " + comVector.size());
save.close(); // This also closes saveFile.
}
catch(Exception exc){
exc.printStackTrace();
}
for (Cases law_case : comVector) {
System.out.println("Name: " + law_case.caseName);
System.out.println("Client: " + law_case.client);
System.out.println("Case Type: " + law_case.caseType);
System.out.println("Case State: " + law_case.caseState);
System.out.println("Case Revenue: " + law_case.closedCaseRevenue);
System.out.println();
}
return casesVector;
}
最佳答案
编辑:因此要附加到 vector (如果它已经存在)...
使用检查现有文件
File f = new File(FileName);
if(f.exists())
/* Read in the vector from the file using an object input stream on the file */
else
/* make a new vector */
然后读入您的输入并完全按照您的输入输出它,但是当您使 FileOutputStream 不包含 true 标志时,这将导致您每次添加一个新 vector ,而不是仅使用覆盖当前 vector 新的、正确的。
原版
您的实现存在的问题是,每次写入保存文件时都会附加一个新数组。因此,每当您尝试从文件中读取数据时,您总是会得到您创建的第一个数组。
我不确定您是否希望每次都用新数组覆盖数组,但您应该在添加更多案例之前读取当前数组,或者不将 FileWriter 构造函数的附加标志设置为 true取决于您想要的结果。
关于Java 从文件中读取对象 vector 仅读取 vector 中的第一个对象,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/12902317/