问题序列化和反序列化的ArrayList [英] Problem serializing and deserializing ArrayList

问题描述

每当我试图序列文件出现错误：FileNotFound。不知道为什么。这是我的FileHelper code：

 包org.stocktwits.helper;

进口java.io.ByteArrayInputStream中;
进口java.io.ByteArrayOutputStream中;
进口的java.io.File;
进口java.io.FileInputStream中;
进口java.io.FileOutputStream中;
进口java.io.IOException异常;
进口的java.io.InputStream;
进口java.io.ObjectInputStream中;
进口java.io.ObjectOutput中;
进口java.io.ObjectOutputStream中;
进口的java.util.ArrayList;

进口org.stocktwits.model.Quote;

公共类FileHelper {
    //返回一个字节数组的文件的内容。
    公共静态的byte [] getBytesFromFile（档案文件）抛出IOException异常{
        InputStream的是=新的FileInputStream（文件）;

        //获取文件的大小
        长长度= file.length（）;

        //您不能创建使用长类型的数组。
        //它需要一个int类型。
        //之前转换成int类型，检查
        //确保文件不大于Integer.MAX_VALUE。
        如果（长度＆GT;为Integer.MAX_VALUE）{
            //文件过大
        }

        //创建字节数组来保存数据
        字节[]字节=新字节[（INT）长]。

        //读取的字节数
        INT偏移= 0;
        INT numRead = 0;
        而（偏移＆LT; bytes.length
               ＆功放;＆安培; （numRead = is.​​read（字节，胶印，bytes.length偏移））＆GT; = 0）{
            胶印+ = numRead;
        }

        //确保所有字节都被读入
        如果（偏移＆LT; bytes.length）{
            抛出新的IOException异常（无法完全读取文件+ file.getName（））;
        }

        //关闭输入流，并返回字节
        is.close（）;
        返回字节;
    }

    公共静态无效serializeQuotes（ArrayList中＆LT;报价＆GT;引号）{
        尝试 {
            //序列化到一个文件
            的ObjectOutput OUT =新的ObjectOutputStream（新的FileOutputStream（quotes.ser））;
            out.writeObject（引号）;
            out.close（）;

            //序列化到一个字节数组
            ByteArrayOutputStream BOS =新ByteArrayOutputStream（）;
            OUT =新的ObjectOutputStream（BOS）;
            out.writeObject（引号）;
            out.close（）;

            //获取序列化对象的字节
            // byte []的BUF = bos.toByteArray（）;
        }赶上（IOException异常E）{
            的System.out.println（E）;
        }
    }

    @燮pressWarnings（未登记）
    公共静态无效deserializeQuotes（ArrayList中＆LT;报价＆GT;引号）{
        尝试 {
            //从文件反序列化
            档案文件=新的文件（quotes.ser）;
            ObjectInputStream中的=新的ObjectInputStream（新的FileInputStream（文件））;
            //反序列化对象
            报价=（ArrayList的＆LT;报价＆GT;）in.readObject（）;
            附寄（）;

            //获取一些字节数组数据
            字节[]字节= FileHelper.getBytesFromFile（文件）;
            //看到读入文件到一个字节数组此方法的实现

            //从一个字节数组反序列化
            在=新的ObjectInputStream（新ByteArrayInputStream的（字节））;
            报价=（ArrayList的＆LT;报价＆GT;）in.readObject（）;
            附寄（）;
        }赶上（ClassNotFoundException异常E）{
            的System.out.println（E）;
        }赶上（IOException异常E）{
            的System.out.println（E）;
        }
    }
}
 

解决方案

我少code解决了这个问题：

 私人无效serializeQuotes（）{
        FileOutputStream中FOS;
        尝试 {
            FOS = openFileOutput（Constants.FILENAME，Context.MODE_PRIVATE）;
            ObjectOutputStream的OOS =新的ObjectOutputStream（FOS）;
            oos.writeObject（引号）;
            oos.close（）;
        }赶上（FileNotFoundException异常E）{
            e.printStackTrace（）;
        }赶上（IOException异常E）{
            e.printStackTrace（）;
        }
    }

    @燮pressWarnings（未登记）
    私人无效deserializeQuotes（）{
        尝试{
            的FileInputStream FIS = openFileInput（Constants.FILENAME）;
            ObjectInputStream的OIS =新的ObjectInputStream（FIS）;
            报价=（ArrayList的＆LT;报价＆GT;）ois.readObject（）;
        }赶上（FileNotFoundException异常E）{
            e.printStackTrace（）;
        }赶上（IOException异常E）{
            e.printStackTrace（）;
        }赶上（ClassNotFoundException异常E）{
            e.printStackTrace（）;
        }
    }
 

BOOM SHAKA LAKA。

Anytime I try to serialize a file I get the error: FileNotFound. Not sure why. Here is my FileHelper code:

package org.stocktwits.helper;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutput;
import java.io.ObjectOutputStream;
import java.util.ArrayList;

import org.stocktwits.model.Quote;

public class FileHelper {
    // Returns the contents of the file in a byte array.
    public static byte[] getBytesFromFile(File file) throws IOException {
        InputStream is = new FileInputStream(file);

        // Get the size of the file
        long length = file.length();

        // You cannot create an array using a long type.
        // It needs to be an int type.
        // Before converting to an int type, check
        // to ensure that file is not larger than Integer.MAX_VALUE.
        if (length > Integer.MAX_VALUE) {
            // File is too large
        }

        // Create the byte array to hold the data
        byte[] bytes = new byte[(int)length];

        // Read in the bytes
        int offset = 0;
        int numRead = 0;
        while (offset < bytes.length
               && (numRead=is.read(bytes, offset, bytes.length-offset)) >= 0) {
            offset += numRead;
        }

        // Ensure all the bytes have been read in
        if (offset < bytes.length) {
            throw new IOException("Could not completely read file "+file.getName());
        }

        // Close the input stream and return bytes
        is.close();
        return bytes;
    }

    public static void serializeQuotes(ArrayList<Quote> quotes){
        try {
            // Serialize to a file
            ObjectOutput out = new ObjectOutputStream(new FileOutputStream("quotes.ser"));
            out.writeObject(quotes);
            out.close();

            // Serialize to a byte array
            ByteArrayOutputStream bos = new ByteArrayOutputStream() ;
            out = new ObjectOutputStream(bos) ;
            out.writeObject(quotes);
            out.close();

            // Get the bytes of the serialized object
            //byte[] buf = bos.toByteArray();
        } catch (IOException e) {
            System.out.println(e);
        }
    }

    @SuppressWarnings("unchecked")
    public static void deserializeQuotes(ArrayList<Quote> quotes){
        try {
            // Deserialize from a file
            File file = new File("quotes.ser");
            ObjectInputStream in = new ObjectInputStream(new FileInputStream(file));
            // Deserialize the object
            quotes = (ArrayList<Quote>) in.readObject();
            in.close();

            // Get some byte array data
            byte[] bytes = FileHelper.getBytesFromFile(file);
            // see Reading a File into a Byte Array for the implementation of this method

            // Deserialize from a byte array
            in = new ObjectInputStream(new ByteArrayInputStream(bytes));
            quotes = (ArrayList<Quote>) in.readObject();
            in.close();
        } catch (ClassNotFoundException e) {
            System.out.println(e);
        } catch (IOException e) {
            System.out.println(e);
        }
    }   
}

解决方案

I solved it with less code:

private void serializeQuotes(){
        FileOutputStream fos;
        try {
            fos = openFileOutput(Constants.FILENAME, Context.MODE_PRIVATE);
            ObjectOutputStream oos = new ObjectOutputStream(fos);
            oos.writeObject(quotes); 
            oos.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }catch(IOException e){
            e.printStackTrace();
        }
    }

    @SuppressWarnings("unchecked")
    private void deserializeQuotes(){
        try{
            FileInputStream fis = openFileInput(Constants.FILENAME);
            ObjectInputStream ois = new ObjectInputStream(fis);
            quotes = (ArrayList<Quote>) ois.readObject();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }catch(IOException e){
            e.printStackTrace();
        }catch(ClassNotFoundException e){
            e.printStackTrace();
        }
    }

BOOM SHAKA LAKA.

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