Question

我是序列化的新手。

我试着编写简单的代码。我得到了奇怪的结果。我不明白。

我有这段代码：

package easybudda.fakesizeof;

import java.io.*;

public class FakeSizeOf {
    public static void main(String[] args) throws IOException {
        Object[] arr = { new Boolean(true), new Character('ы'), new Integer(13), new Long(69L), new Double(3.14) };
        ByteArrayOutputStream outStream = new ByteArrayOutputStream();
        ObjectOutputStream objOutStream = new ObjectOutputStream(outStream);

        for ( Object obj : arr ) {
            outStream.reset();
            objOutStream.writeObject(obj);
            objOutStream.flush();
            System.out.println(obj.getClass().getSimpleName() + ": " + outStream.size());
        }

        System.out.println("\nUsing predefined methods:");
        outStream.reset();
        objOutStream.write(13);
        objOutStream.flush();
        System.out.println("write with int as data: " + outStream.size());

        outStream.reset();
        objOutStream.writeBoolean(false);
        objOutStream.flush();
        System.out.println("writeBoolean: " + outStream.size());

        outStream.reset();
        objOutStream.writeByte(1);
        objOutStream.flush();
        System.out.println("writeByte: " + outStream.size());

        outStream.reset();
        objOutStream.writeChar('ы');
        objOutStream.flush();
        System.out.println("writeChar: " + outStream.size());

        outStream.reset();
        objOutStream.writeDouble(3.14);
        objOutStream.flush();
        System.out.println("writeDouble: " + outStream.size());

        outStream.reset();
        objOutStream.writeInt(13);
        objOutStream.flush();
        System.out.println("writeInt: " + outStream.size());

        outStream.reset();
        objOutStream.writeLong(69L);
        objOutStream.flush();
        System.out.println("writeLong: " + outStream.size());
    }
}

输出：

Boolean: 43
Character: 46
Integer: 77
Long: 51
Double: 53

Using predefined methods:
write with int as data: 3
writeBoolean: 3
writeByte: 3
writeChar: 4
writeDouble: 10
writeInt: 6
writeLong: 10

有人可以为我开出这些结果吗？

1.例如int - 4字节（6输出） - 为什么？

2.为什么阵列如此巨大？

Answer 1

ObjectOutputStream会为其编写的所有内容添加类型信息。请参阅Object Serialization Specification，协议章节：

类所写的所有原始数据都被缓冲并包装在块数据记录中，无论数据是在writeObject方法中写入流还是从writeObject外部直接写入流中。方法

例如，writeInt(13)写[119,4,0,0,0,13]，这意味着

TC_BLOCKDATA,size=4 bytes,0,0,0,13.

序列化奇怪的结果

1 个答案: