java深複製討論

第一種:/** * 實現對象的複製 *  * @author jianhua.fengjh */@SuppressWarnings("all")public class UCloneUtil {    /**     * 序列化實現深複製     *      * 通過Jdk原生對象序列化流實現深度複製，雖然簡便，但是效能非常之低。     * @TODO 後續要改成遞迴複製方式實現     *      * @param src     * @return     * @throws IOException     * @throws ClassNotFoundException     */    @Deprecated    public static <T> T deepClone(T src) throws IOException, ClassNotFoundException {        T t = null;        ObjectOutputStream oos = null;        ObjectInputStream ois = null;        try {            ByteArrayOutputStream baos = new ByteArrayOutputStream();            oos = new ObjectOutputStream(baos);            oos.writeObject(src);            oos.flush();            ois = new ObjectInputStream(new ByteArrayInputStream(baos.toByteArray()));            t = (T) ois.readObject();        } finally {            if (ois != null) {                ois.close();            }            if (oos != null) {                oos.close();            }        }        return t;    }} 第二種import com.thoughtworks.xstream.XStream;@SuppressWarnings("all")public class XCloneUtil {    private static XStream xstream = new XStream();    public static <T> T deepClone(T t) {        return (T) xstream.fromXML(xstream.toXML(t));    }} 第三種public class FastCloneUtil {    public static <T> T deepClone(T src) throws IOException, ClassNotFoundException {        T t = null;        ObjectInputStream ois = null;        ObjectOutputStream oos = null;        try {            FastByteArrayOutputStream fbos = new FastByteArrayOutputStream();            oos = new ObjectOutputStream(fbos);            oos.writeObject(src);            oos.flush();            ois = new ObjectInputStream(fbos.getInputStream());            t = (T) ois.readObject();        } finally {            if (ois != null) {                ois.close();            }            if (oos != null) {                oos.close();            }        }        return t;    }}  import java.io.InputStream;/** * ByteArrayInputStream implementation that does not synchronize methods. */public class FastByteArrayInputStream extends InputStream {    /**     * Our byte buffer     */    protected byte[] buf   = null;    /**     * Number of bytes that we can read from the buffer     */    protected int    count = 0;    /**     * Number of bytes that have been read from the buffer     */    protected int    pos   = 0;    public FastByteArrayInputStream(byte[] buf, int count){        this.buf = buf;        this.count = count;    }    public final int available() {        return count - pos;    }    public final int read() {        return (pos < count) ? (buf[pos++] & 0xff) : -1;    }    public final int read(byte[] b, int off, int len) {        if (pos >= count) {            return -1;        }        if ((pos + len) > count) {            len = (count - pos);        }        System.arraycopy(buf, pos, b, off, len);        pos += len;        return len;    }    public final long skip(long n) {        if ((pos + n) > count) {            n = count - pos;        }        if (n < 0) {            return 0;        }        pos += n;        return n;    }}  import java.io.InputStream;import java.io.OutputStream;/** * ByteArrayOutputStream implementation that doesn't synchronize methods and doesn't copy the data on toByteArray(). */public class FastByteArrayOutputStream extends OutputStream {    /**     * Buffer and size     */    protected byte[] buf  = null;    protected int    size = 0;    /**     * Constructs a stream with buffer capacity size 5K     */    public FastByteArrayOutputStream(){        this(5 * 1024);    }    /**     * Constructs a stream with the given initial size     */    public FastByteArrayOutputStream(int initSize){        this.size = 0;        this.buf = new byte[initSize];    }    /**     * Ensures that we have a large enough buffer for the given size.     */    private void verifyBufferSize(int sz) {        if (sz > buf.length) {            byte[] old = buf;            buf = new byte[Math.max(sz, 2 * buf.length)];            System.arraycopy(old, 0, buf, 0, old.length);            old = null;        }    }    public int getSize() {        return size;    }    /**     * Returns the byte array containing the written data. Note that this array will almost always be larger than the     * amount of data actually written.     */    public byte[] getByteArray() {        return buf;    }    public final void write(byte b[]) {        verifyBufferSize(size + b.length);        System.arraycopy(b, 0, buf, size, b.length);        size += b.length;    }    public final void write(byte b[], int off, int len) {        verifyBufferSize(size + len);        System.arraycopy(b, off, buf, size, len);        size += len;    }    public final void write(int b) {        verifyBufferSize(size + 1);        buf[size++] = (byte) b;    }    public void reset() {        size = 0;    }    /**     * Returns a ByteArrayInputStream for reading back the written data     */    public InputStream getInputStream() {        return new FastByteArrayInputStream(buf, size);    }}第四種import com.rits.cloning.Cloner;public class VeryFastCloneUtil {    public static <T> T deepClone(T src) {        Cloner cloner = new Cloner();        return cloner.deepClone(src);    }}

最快的是第四種, 搞技術的代碼一看就懂, 不多說.