java 各种copy

java里面有许多需要copy的地方,比如copy文件,copy数组,现总结如下

(1)copy文件

public static void copyFile(String resourceFileName, String targetFileName)
			throws IOException {
		File resourceFile = new File(resourceFileName);
		File targetFile = new File(targetFileName);
		if (!resourceFile.exists()) {
			System.out.println("[copyFile ]: resource file has not been found:"
					+ resourceFileName);
		}
		if (!resourceFile.isFile()) {
			System.out.println("[copyFile ]: directory can not be copyed:"
					+ resourceFileName);
		}

		if (targetFile.isDirectory()) {
			targetFile = new File(targetFile, resourceFile.getName());
		}

		FileInputStream resource = null;
		FileOutputStream target = null;
		try {
			resource = new FileInputStream(resourceFile);
			target = new FileOutputStream(targetFile);
			copyFile(resourceFile, targetFile);
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			if (resource != null) {
				resource.close();
			}
			if (target != null) {
				target.close();
			}
		}
	}

/**
	 * 
	 * @param srcFile
	 *            :must be regular file,can not be folder;
	 * @param targetFile
	 *            :must be regular file,can not be folder;
	 * @throws IOException
	 */
	public static void copyFile(File srcFile, File targetFile)
			throws IOException {
		FileInputStream in = new FileInputStream(srcFile);

		FileOutputStream out = new FileOutputStream(targetFile);
		copyFile(in, out);

	}
public static void copyFile(InputStream in, FileOutputStream target)
			throws IOException {
		// File targetFile = new File(targetFileName);
		// FileOutputStream target = null;
		// if (targetFile.isDirectory())
		// {
		// targetFile = new File(targetFile, simpleName);
		// }
		try {
			// target = new FileOutputStream(targetFile);
			byte[] buffer = new byte[BUFF_SIZE];
			int byteNum;

			while ((byteNum = in.read(buffer)) != NEGATIVE_ONE) {
				target.write(buffer, 0, byteNum);

			}
			System.out.println("[SystemUtil:copyFile]:file copy successfully!");
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			if (in != null) {
				in.close();
				in = null;
			}
			if (target != null) {
				target.close();
				target = null;
			}
		}
	}

 

(2)copy数组

/***
	 * 合并字节数组
	 * 
	 * @param a
	 * @return
	 */
	public static byte[] mergeArray(byte[]... a) {
		// 合并完之后数组的总长度
		int index = 0;
		int sum = 0;
		for (int i = 0; i < a.length; i++) {
			sum = sum + a[i].length;
		}
		byte[] result = new byte[sum];
		for (int i = 0; i < a.length; i++) {
			int lengthOne = a[i].length;
			if (lengthOne == 0) {
				continue;
			}
			// 拷贝数组
			System.arraycopy(a[i], 0, result, index, lengthOne);
			index = index + lengthOne;
		}
		return result;
	}
/***
	 * append a byte.
	 * 
	 * @param a
	 * @param b
	 * @return
	 */
	public static byte[] appandByte(byte[] a, byte b) {
		int length = a.length;
		byte[] resultBytes = new byte[length + 1];
		System.arraycopy(a, 0, resultBytes, 0, length);
		resultBytes[length] = b;
		return resultBytes;
	}
public static byte[] copyByte(int start, int length, byte[] source) {
		byte[] des = new byte[length];
		System.arraycopy(source, start, des, 0, length);
		return des;
	}

 

(3)copy List

/***
	 * 复制 list
	 * @param srcList
	 * @param start
	 * @param length
	 * @return
	 */
	public static List copyList(List srcList,int start,int length){
		if(ValueWidget.isNullOrEmpty(srcList)){
			return null;
		}
		List resultList=new ArrayList();
		for(int i=start;i<length+start&& i<srcList.size();i++){
			resultList.add(srcList.get(i));
		}
		return resultList;
	}

 测试:

@Test
	public void test_ArrayList_remove(){
		List list=new ArrayList<String>();
		int range=3;
		list.add("aa");
		list.add("bb");
		list.add("cc");
		list.add("dd");
		list.add("ee");
		list.add("ff");
//		if(list.size()>range){//excel前两行是标题
//			System.out.println("移除序号"+range+"....");
//			for(int j=range;j<=list.size()+1;j++){
//				Object obj32=list.remove(range);
//			}
//		}
		System.out.println( SystemHWUtil. copyList(list, 0, 14));
	}

 参考:

http://www.baidu.com/link?url=Wwh8KqbUeOaaKFCcp8xAQ8ALHUuunhm1kR95EAbhk20LkxkL_8pQbFCfnaoKqP1KX4pzf8lCeRWWFk2fEDqK5a

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