今天遇到一个需求，获取所有apk的签名的MD5，下面是我使用Java SE实现的一个工具，贴出核心源代码，希望给有需要的朋友有所帮助。

界面如下：

只需要制定.apk文件所在的目录即可，核心代码如下：

public class ReadCmdLine {	private static MD5Window window;	private static String inputPath;	public static void main(String args[]) {		window = new MD5Window();		window.setVisible(true);		initWindow();	}	private static void initWindow() {		// 文件目录文本框		window.getFilePathButton().addActionListener(new ActionListener() {			@Override			public void actionPerformed(ActionEvent arg0) {				JFileChooser jfc = new JFileChooser();				jfc.setFileSelectionMode(JFileChooser.FILES_AND_DIRECTORIES);				jfc.showDialog(new JLabel(), "选择");				File file = jfc.getSelectedFile();				notDirectoryExcute(file);			}		});		// 开始运行按钮		window.getBeginButton().addActionListener(new ActionListener() {			@Override			public void actionPerformed(ActionEvent arg0) {				inputPath = window.getJTextFiled();				if (inputPath != null && !"".equals(inputPath.trim())) {					notDirectoryExcute(new File(inputPath));				}			}		});		// 清空结果按钮		window.getClearButton().addActionListener(new ActionListener() {			@Override			public void actionPerformed(ActionEvent arg0) {				window.setTextArea("");			}		});	}	/**	 * 判断是否是目录，如果不是则执行	 * 	 * @param file	 */	public static void notDirectoryExcute(File file) {		if (file.isDirectory()) {			inputPath = file.getAbsolutePath();			window.setJTextFiled(inputPath);			File[] fiels = file.listFiles();			for (int i = 0; i < fiels.length; i++) {				String absPath = fiels[i].getAbsolutePath();				if (absPath.contains(".apk")) {					excute(absPath);				}			}		} else {			JOptionPane.showMessageDialog(window, "请选择目录");		}	}	/**	 * 核心逻辑	 * 	 * @param absPath	 */	public static void excute(String absPath) {		// 1、从.apk中读取CERT.RSA文件		String appName = absPath.substring(absPath.lastIndexOf("_") + 1,						absPath.lastIndexOf("."));		try {			if (absPath != null) {				readZipFile(absPath);			}		} catch (Exception e) {			e.printStackTrace();		}		// 2、执行 keytool命令获取MD5		Process process = null;		List
    
      processList = new ArrayList
     
      ();		try {			process = Runtime.getRuntime().exec(				"keytool -printcert -file D:/test/CERT.RSA");			BufferedReader input = new BufferedReader(new InputStreamReader(				process.getInputStream()));			String line = "";			while ((line = input.readLine()) != null) {				processList.add(line);			}			input.close();		} catch (IOException e) {			e.printStackTrace();		}		// 过滤内容		for (String line : processList) {			if (line.contains("MD5")) {				window.setTextArea(window.getTextArea()					+ String.format("%-30s", appName) + line.trim() + "\n");			}		}	}	/**	 * 读取压缩文件内容	 * 	 * @param file 压缩文件的路径	 * @throws Exception	 */	public static void readZipFile(String file) throws Exception {		ZipFile zf = new ZipFile(file);		InputStream in = new BufferedInputStream(new FileInputStream(file));		ZipInputStream zin = new ZipInputStream(in);		File outFile = new File("D:\\test\\CERT.RSA");		OutputStream out = new FileOutputStream(outFile);		InputStream rsaStream = zf.getInputStream(zf				.getEntry("META-INF/CERT.RSA"));		byte[] buf1 = new byte[1024];		int len;		while ((len = rsaStream.read(buf1)) > 0) {			out.write(buf1, 0, len);		}		rsaStream.close();		out.close();		in.close();		zin.closeEntry();	}}