import java.util.ArrayList; public class Size { static long size=0; private static ArrayList<String> filelist=new ArrayList<String>(); public static void main(String[] args) { Size s=new Size(); String filePath="D:\软件"; s.getFiles(filePath); } //通过递归得到某一路径下所有的目录及文件 void getFiles(String filePath) { File root=new File(filePath); File[] files=root.listFiles(); for(File file:files) { if(file.isDirectory()) { getFiles(file.getAbsolutePath()); filelist.add(file.getAbsolutePath()); } else { size+=file.getAbsolutePath().length(); } } System.out.println("大小是"+size); } }
这个程序的运行结果为:
大小是431
大小是868
大小是964
大小是1054
大小是1254
大小是1322
大小是2013
大小是2259
大小是2338
大小是2338
大小是3655
package shuruliu; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.InputStream; import java.io.OutputStream; import java.security.Key; import java.security.SecureRandom; import javax.crypto.Cipher; import javax.crypto.CipherInputStream; import javax.crypto.CipherOutputStream; import javax.crypto.KeyGenerator; public class JiaMi { Key key; public void TestDES(String str) { getKey(str);//生成密匙 } public void getKey(String strKey) { try { KeyGenerator _generator = KeyGenerator.getInstance("DES"); _generator.init(new SecureRandom(strKey.getBytes())); this.key = _generator.generateKey(); _generator = null; } catch (Exception e) { throw new RuntimeException("Error initializing SqlMap class. Cause: " + e); } } public void encrypt(String file, String destFile) throws Exception { Cipher cipher = Cipher.getInstance("DES"); // cipher.init(Cipher.ENCRYPT_MODE, getKey()); cipher.init(Cipher.ENCRYPT_MODE, this.key); InputStream is = new FileInputStream(file); OutputStream out = new FileOutputStream(destFile); CipherInputStream cis = new CipherInputStream(is, cipher); byte[] buffer = new byte[1024]; int r; while ((r = cis.read(buffer)) > 0) { out.write(buffer, 0, r); } cis.close(); is.close(); out.close(); } public void decrypt(String file, String dest) throws Exception { Cipher cipher = Cipher.getInstance("DES"); cipher.init(Cipher.DECRYPT_MODE, this.key); InputStream is = new FileInputStream(file); OutputStream out = new FileOutputStream(dest); CipherOutputStream cos = new CipherOutputStream(out, cipher); byte[] buffer = new byte[1024]; int r; while ((r = is.read(buffer)) >= 0) { System.out.println(); cos.write(buffer, 0, r); } cos.close(); out.close(); is.close(); } public static void main(String[] args){ TestDES td = new TestDES(); try { td.encrypt("e:/r.txt", "e:/r加密后.txt"); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } //加密 try { td.encrypt("e:/r加密后.txt", "e:/r解密后.txt"); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } //解密 } }
先建立一个文件,然后在文件里写入这个是要加密的文件,然后加密之后,形成一堆乱码,然后解密之后,文件里的内容又变为了,这个是要加密的文件。