Java对象的序列化和反序列化源码阅读

package com.test.java.serial;

import lombok.Builder;
import lombok.Data;

import java.io.Serializable;

/**
 * @author Ryan Miao
 */
@Data
@Builder
public class Foo implements Serializable {

    private static final String LOGGER = "logger";
    public static final String PUB_STATIC_FINAL = "publicStaticFinal";
    public static String PUB_STATIC;

    public String fa;
    private String fb;
    transient public String ta;
    transient private String tb;
}

public class TestSerialize {

    private static final String filename = "D:/test.txt";

    @Test
    public void testSer() throws IOException, ClassNotFoundException {
        final Foo foo = Foo.builder()
                .fa("fa")
                .fb("fb")
                .ta("ta")
                .tb("tb")
                .build();

        Foo.PUB_STATIC  = "test";

        ObjectOutputStream os = new ObjectOutputStream(
                new FileOutputStream(filename));
        os.writeObject(foo);
        os.flush();
        os.close();

    }

    @Test
    public void testRead() throws IOException, ClassNotFoundException {
        ObjectInputStream is = new ObjectInputStream(new FileInputStream(filename));
        Foo foo2 = (Foo) is.readObject();
        is.close();

        Assert.assertEquals("fa", foo2.getFa());
        Assert.assertEquals("fb", foo2.getFb());
        Assert.assertEquals(null, foo2.getTa());
        Assert.assertEquals(null, foo2.getTb());

        Assert.assertNull(foo2.PUB_STATIC);
    }
}

// remaining cases
if (obj instanceof String) {
    writeString((String) obj, unshared);
} else if (cl.isArray()) {
    writeArray(obj, desc, unshared);
} else if (obj instanceof Enum) {
    writeEnum((Enum<?>) obj, desc, unshared);
} else if (obj instanceof Serializable) {
    writeOrdinaryObject(obj, desc, unshared);
} else {
    if (extendedDebugInfo) {
        throw new NotSerializableException(
            cl.getName() + "\n" + debugInfoStack.toString());
    } else {
        throw new NotSerializableException(cl.getName());
    }
}

public final void writeObject(Object obj) throws IOException {
    if (enableOverride) {
        writeObjectOverride(obj);
        return;
    }
    try {
        writeObject0(obj, false);
    } catch (IOException ex) {
        if (depth == 0) {
            writeFatalException(ex);
        }
        throw ex;
    }
}

private void writeObject0(Object obj, boolean unshared)
        throws IOException{
    boolean oldMode = bout.setBlockDataMode(false);depth++;
    try {
        //省略若干行
        for (;;) {
            // 省略若干行
            desc = ObjectStreamClass.lookup(cl, true);
            //省略若干行
        }
        //省略若干行
        if (obj instanceof String) {
            writeString((String) obj, unshared);
        } else if (cl.isArray()) {
            writeArray(obj, desc, unshared);
        } else if (obj instanceof Enum) {
            writeEnum((Enum<?>) obj, desc, unshared);
        } else if (obj instanceof Serializable) {
            writeOrdinaryObject(obj, desc, unshared);
        } else {
            //....
        }
    } finally {
        depth--;
        bout.setBlockDataMode(oldMode);
    }
}

static ObjectStreamClass lookup(Class<?> cl, boolean all) {
    //省略若干行
    if (entry == null) {
        try {
            entry = new ObjectStreamClass(cl);
        } catch (Throwable th) {
            entry = th;
        }
        //.....
    }
    //省略若干行
}

private ObjectStreamClass(final Class<?> cl) {
    //省略无数行以及括号
    writeObjectMethod = getPrivateMethod(cl, "writeObject",
                            new Class<?>[] { ObjectOutputStream.class },
                            Void.TYPE);
    readObjectMethod = getPrivateMethod(cl, "readObject",
                            new Class<?>[] { ObjectInputStream.class },
                            Void.TYPE);
    //省略无数行

private void writeSerialData(Object obj, ObjectStreamClass desc)
        throws IOException
{
    ObjectStreamClass.ClassDataSlot[] slots = desc.getClassDataLayout();
    for (int i = 0; i < slots.length; i++) {
        ObjectStreamClass slotDesc = slots[i].desc;
        if (slotDesc.hasWriteObjectMethod()) {
            //....
            try {
                curContext = new SerialCallbackContext(obj, slotDesc);
                bout.setBlockDataMode(true);
                slotDesc.invokeWriteObject(obj, this);
                bout.setBlockDataMode(false);
                bout.writeByte(TC_ENDBLOCKDATA);
            } finally {
                //...
            }

            curPut = oldPut;
        } else {
            defaultWriteFields(obj, slotDesc);
        }
    }
}

private void writeObject(java.io.ObjectOutputStream s)
    throws java.io.IOException{
    // Write out element count, and any hidden stuff
    int expectedModCount = modCount;
    s.defaultWriteObject();

    // Write out size as capacity for behavioural compatibility with clone()
    s.writeInt(size);

    // Write out all elements in the proper order.
    for (int i=0; i<size; i++) {
        s.writeObject(elementData[i]);
    }

    if (modCount != expectedModCount) {
        throw new ConcurrentModificationException();
    }
}

private void readObject(java.io.ObjectInputStream s)
    throws java.io.IOException, ClassNotFoundException {
    elementData = EMPTY_ELEMENTDATA;

    // Read in size, and any hidden stuff
    s.defaultReadObject();

    // Read in capacity
    s.readInt(); // ignored

    if (size > 0) {
        // be like clone(), allocate array based upon size not capacity
        ensureCapacityInternal(size);

        Object[] a = elementData;
        // Read in all elements in the proper order.
        for (int i=0; i<size; i++) {
            a[i] = s.readObject();
        }
    }
}