anroid&java工具类

      越来越发现，整理一些常用的工具接口，对于编程开发人员来说越来越重要，以本文为契机，开始对常用的工具接口进行整理，不断update，起到事半功倍的作用。

     

public class Tools {

	private final static int DEFAULT_BUFFER_SIZE = 1024;

	/**
	 * 将文件大小由字节转化为M
	 * 
	 * @param size
	 * @return
	 */
	public static String sizeToM(long size) {
		if (size / 1024 / 1024 >= 1) {
			return size / 1024 / 1024 + (size / 1024 % 1024 / 1024.0 + "").substring(1, 3) + "MB";
		} else {
			return size / 1024 + (size % 1024 / 1024.0 + "").substring(1, 3) + "KB";
		}
	}

	/**
	 * 将字符串写入指定文件(当指定的父路径中文件夹不存在时，会最大限度去创建，以保证保存成功！)
	 * 
	 * @param res
	 *            原字符串
	 * @param filePath
	 *            文件路径
	 * @return 成功标记
	 */
	public static boolean string2File(String res, String filePath) {
		boolean flag = true;
		BufferedReader bufferedReader = null;
		BufferedWriter bufferedWriter = null;
		try {
			File distFile = new File(filePath);
			if (!distFile.getParentFile().exists())
				distFile.getParentFile().mkdirs();
			bufferedReader = new BufferedReader(new StringReader(res));
			bufferedWriter = new BufferedWriter(new FileWriter(distFile));
			char buf[] = new char[1024]; // 字符缓冲区
			int len;
			while ((len = bufferedReader.read(buf)) != -1) {
				bufferedWriter.write(buf, 0, len);
			}
			bufferedWriter.flush();
			bufferedReader.close();
			bufferedWriter.close();
		} catch (IOException e) {
			e.printStackTrace();
			flag = false;
			return flag;
		} finally {
			if (bufferedReader != null) {
				try {
					bufferedReader.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}
		return flag;
	}

	/**
	 * 文本文件转换为指定编码的字符串
	 * 
	 * @param file
	 *            文本文件
	 * @param encoding
	 *            编码类型
	 * @return 转换后的字符串
	 * @throws IOException
	 */
	public static String file2String(File file, String encoding) {
		InputStreamReader reader = null;
		StringWriter writer = new StringWriter();
		try {
			if (encoding == null || "".equals(encoding.trim())) {
				reader = new InputStreamReader(new FileInputStream(file), encoding);
			} else {
				reader = new InputStreamReader(new FileInputStream(file));
			}
			// 将输入流写入输出流
			char[] buffer = new char[DEFAULT_BUFFER_SIZE];
			int n = 0;
			while (-1 != (n = reader.read(buffer))) {
				writer.write(buffer, 0, n);
			}
		} catch (Exception e) {
			e.printStackTrace();
			return null;
		} finally {
			if (reader != null)
				try {
					reader.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
		}
		// 返回转换结果
		if (writer != null)
			return writer.toString();
		else
			return null;
	}

	/**
	 * 获取当前系统的版本
	 * 
	 * @return
	 */
	public static String currentSystemVersion() {
		return Build.VERSION.RELEASE;
	}

	/*
	 * IP正则表达式的判断
	 */
	public static boolean matchIP(String ip) {
		// ip正则表达式
		String regex = "([1-9]|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])(\\.(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])){3}";
		Pattern pattern = Pattern.compile(regex);
		Matcher matcher = pattern.matcher(ip);
		return matcher.matches();
	}

	/**
	 * 解析IP地址
	 * 
	 * @param ip
	 */
	public static String[] resolutionIP(String ip) {
		return ip.split("\\.");
	}

	/**
	 * 把字节数组转换成Bitmap
	 * 
	 * @param b
	 * @return
	 */
	public static Bitmap byte2Bitmap(byte[] b) {
		if (b.length != 0) {
			return BitmapFactory.decodeByteArray(b, 0, b.length);
		} else {
			return null;
		}
	}

	/**
	 * 把Bitmap转换成字节数组
	 * 
	 * @param bm
	 * @return
	 */
	public static byte[] bitmap2Bytes(Bitmap bm) {
		ByteArrayOutputStream baos = new ByteArrayOutputStream();
		bm.compress(Bitmap.CompressFormat.PNG, 100, baos);
		return baos.toByteArray();
	}
	
	/**
	 * 获取当前可用内存大小
	 * 
	 * @return
	 */
	public static String getAvailMemory(Context context) {
		ActivityManager am = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
		MemoryInfo mi = new MemoryInfo();
		am.getMemoryInfo(mi);
		System.out.println("mi.availMem;" + mi.availMem);

		return Formatter.formatFileSize(context, mi.availMem);// 将获取的内存大小规格化
	}

	/**
	 * 获取总的内存大小
	 * 
	 * @return
	 */
	public static String getTotalMemory(Context context) {
		String str1 = "/proc/meminfo";// 系统内存信息文件
		String str2;
		String[] arrayOfString;
		long initial_memory = 0;

		try {
			FileReader localFileReader = new FileReader(str1);
			BufferedReader localBufferedReader = new BufferedReader(localFileReader, 8192);
			str2 = localBufferedReader.readLine();// 读取meminfo第一行，系统总内存大小

			arrayOfString = str2.split("\\s+");
			for (String num : arrayOfString) {
				Log.i(str2, num + "\t");
			}

			initial_memory = Integer.valueOf(arrayOfString[1]).intValue() * 1024;// 获得系统总内存，单位是KB，乘以1024转换为Byte
			localBufferedReader.close();

		} catch (IOException e) {
		}
		return Formatter.formatFileSize(context, initial_memory);// Byte转换为KB或者MB，内存大小规格化
	}

}