Question

Java ObjectInputStream。只能写一个对象，不能一直写入是为什么？读出对象也不对。

public static Customer[] rrBank() throws EOFException{
Customer[] cus=new Customer[100];
Customer c;
try {
ObjectInputStream is = new ObjectInputStream(new FileInputStream(
"wxps.txt"));
bankInstance=(Bank)is.readObject();

for(int i=0;i<getBank().getNumOfCustomers();i++){
cus[i]=(Customer) is.readObject();

}
is.close();

} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
return cus;
}

public static void ssBank(){
try {
ObjectOutputStream os = new ObjectOutputStream(
new FileOutputStream("wxps.txt"));
os.writeObject(bankInstance);
for(int i=0;i<getBank().getNumOfCustomers();i++){
System.out.println(getBank().getCustomer(i).getNumOfAccounts());
os.writeObject(getBank().getCustomer(i));
}// 将User对象写进文件
os.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}

}

Answer 1

因为不知道你的Bank和Customer是怎么实现的。所以不容易判断错误的原因。我根据你的情况写了并没有问题。给你参考下吧

import java.io.Serializable;
import java.util.Date;

public class Customer implements Serializable{

    private String name;
    private String surName;
    private double balance;
    private Date birthDay;

    public String getName() {
        return name;
    }

    public Customer setName(String name) {
        this.name = name;
        return this;
    }

    public String getSurName() {
        return surName;
    }

    public Customer setSurName(String surName) {
        this.surName = surName;
        return this;
    }

    public double getBalance() {
        return balance;
    }

    public Customer setBalance(double balance) {
        this.balance = balance;
        return this;
    }

    public Date getBirthDay() {
        return birthDay;
    }

    public Customer setBirthDay(Date birthDay) {
        this.birthDay = birthDay;
        return this;
    }

    public void print(){
        System.out.println("Customer name : "+name+", sur_name : "+surName+" with balance : "+balance);
    }

}

import java.io.*;

public class Bank implements Serializable{

    private String name;
    private String address;
    private Customer[] customers;


    public Bank(final int numOfCustomers){
        customers = new Customer[numOfCustomers];
    }

    public String getName() {
        return name;
    }

    public Bank setName(String name) {
        this.name = name;
        return this;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    public Customer[] getCustomers() {
        return customers;
    }

    public void setCustomers(Customer[] custoemrs) {
        this.customers = custoemrs;
    }

    public Customer getCustomer(final int index){
        return index < 0 || index >= customers.length ? null : customers[index];
    }

    public int getNumOfCustomers(){
        return customers.length;
    }

    public void writeFile(final File file) throws IOException {
        final ObjectOutputStream fout = new ObjectOutputStream(new FileOutputStream(file));
        fout.writeObject(this);
        fout.flush();
        fout.close();
    }

    public Bank setCustomer(final Customer customer, final int index){
        if(index < 0 || index >= customers.length){
            return this;
        } else {
            customers[index] = customer;
            return this;
        }
    }

    public void print(){
        System.out.println("Bank name : "+name+" with " + customers.length+" customers\n");
        for(final Customer c : customers){
            c.print();
        }
    }

    public static Bank readFromFile(final File file) throws IOException, ClassNotFoundException {
        final ObjectInputStream fin = new ObjectInputStream(new FileInputStream(file));
        final Bank ret =  (Bank) fin.readObject();
        fin.close();
        return ret;
    }

}

import java.io.File;
import java.io.IOException;
import java.util.Date;

public class TestBank {

    public static void main(String[] args) throws IOException, ClassNotFoundException {

        final File file = new File("/Users/My/Desktop/bank.data");

        final Bank b = new Bank(2);
        b.setName("BOC")
                .setCustomer(new Customer().setBalance(100.0).setBirthDay(new Date()).setName("Test").setSurName("My"), 0)
                .setCustomer(new Customer().setBalance(200.0).setBirthDay(new Date()).setName("T1").setSurName("My2"), 1)
                .writeFile(file);
        b.print();

        System.out.println("----------------------before read---------------");

        final Bank b1  = Bank.readFromFile(file);
        b1.print();

    }

}

用这三个类试试，希望可以帮到你

Answer 2

读到最后，就报EOF错的。。。。表示读完了。