JAVA 深层拷贝 DeepCopy的使用详解

    public class DeepCopy { 
        /**
         * 深层拷贝
         * 
         * @param <T>
         * @param obj
         * @return
         * @throws Exception
         */ 
        public static <T> T copy(T obj) throws Exception { 
            //是否实现了序列化接口，即使该类实现了，他拥有的对象未必也有... 
            if(Serializable.class.isAssignableFrom(obj.getClass())){ 
                //如果子类没有继承该接口，这一步会报错 
                try { 
                    return copyImplSerializable(obj); 
                } catch (Exception e) { 
                    //这里不处理，会运行到下面的尝试json 
                } 
            } 
            //如果序列化失败，尝试json序列化方式 
            if(hasJson()){ 
                try { 
                    return copyByJson(obj); 
                } catch (Exception e) { 
                    //这里不处理，下面返回null 
                } 
            } 
            return null; 
        } 

        /**
         * 深层拷贝 - 需要类继承序列化接口
         * @param <T>
         * @param obj
         * @return
         * @throws Exception
         */ 
        @SuppressWarnings("unchecked") 
        public static <T> T copyImplSerializable(T obj) throws Exception { 
            ByteArrayOutputStream baos = null; 
            ObjectOutputStream oos = null; 

            ByteArrayInputStream bais = null; 
            ObjectInputStream ois = null; 

            Object o = null; 
            //如果子类没有继承该接口，这一步会报错 
            try { 
                baos = new ByteArrayOutputStream(); 
                oos = new ObjectOutputStream(baos); 
                oos.writeObject(obj); 
                bais = new ByteArrayInputStream(baos.toByteArray()); 
                ois = new ObjectInputStream(bais); 

                o = ois.readObject(); 
                return (T) o; 
            } catch (Exception e) { 
                throw new Exception("对象中包含没有继承序列化的对象"); 
            } finally{ 
                try { 
                    baos.close(); 
                    oos.close(); 
                    bais.close(); 
                    ois.close(); 
                } catch (Exception e2) { 
                    //这里报错不需要处理 
                } 
            } 
        } 

        /**
         * 是否可以使用json
         * @return
         */ 
        private static boolean hasJson(){ 
            try { 
                Class.forName("net.sf.json.JSONObject"); 
                return true; 
            } catch (Exception e) { 
                return false; 
            } 
        } 

        /**
         * 深层拷贝 - 需要net.sf.json.JSONObject
         * @param <T>
         * @param obj
         * @return
         * @throws Exception
         */ 
        @SuppressWarnings("unchecked") 
        public static <T> T copyByJson(T obj) throws Exception { 
            return (T)JSONObject.toBean(JSONObject.fromObject(obj),obj.getClass()); 
        } 
    }