Java MD5 Hash encoding

Dibawah ini adalah fungsi statis untuk memanggil md5 hash dengan fungsi core java MessageDigest(), data type tersebut menghasilkan return md5 hash dengan data type String plaintext

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private static String md5hash(String e) {     String result = "null";     try {         MessageDigest md = MessageDigest.getInstance("MD5");         byte[] hash = md.digest(e.getBytes("UTF-8"));         StringBuilder sb = new StringBuilder(2 * hash.length);         for (byte b : hash) {             sb.append(String.format("%02x", b & 0xff));         }         result = sb.toString();     } catch (UnsupportedEncodingException | NoSuchAlgorithmException ex) {         Logger.getLogger(HelloWorld.class.getName()).log(Level.SEVERE, null, ex);     }     return result; }

Simpan script java dibawah ini dengan nama HelloWorld.java

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import java.io.UnsupportedEncodingException; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; import java.util.logging.Level; import java.util.logging.Logger;   class HelloWorld {           private static String md5hash(String e) {         String result = "null";         try {             MessageDigest md = MessageDigest.getInstance("MD5");             byte[] hash = md.digest(e.getBytes("UTF-8"));             StringBuilder sb = new StringBuilder(2 * hash.length);             for (byte b : hash) {                 sb.append(String.format("%02x", b & 0xff));             }             result = sb.toString();         } catch (UnsupportedEncodingException | NoSuchAlgorithmException ex) {             Logger.getLogger(HelloWorld.class.getName()).log(Level.SEVERE, null, ex);         }         return result;     }         public static void main(String[] args) {         String text = "myplaintext";                   String md5_hash = md5hash(text);         System.out.println("md5 hash result : "+md5_hash+"\n");     } }

Maka dari diatas akan menghasilkan md5 hash "3c5d21f4241582748caf9d6f6507167e" dari input string "myplaintext". Jalankan script java : java HelloWorld.java, hasilnya:

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1	md5 hash result : 3c5d21f4241582748caf9d6f6507167e

Java base64 text encoding

Dibawah ini adalah fungsi statis untuk memanggil base64 encode dengan data type return String plaintext

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private static String encodeData(String e) {     try {         return new String(Base64.getEncoder().encode(e.getBytes()));     } catch (Exception ex) {         return e;     } }

Dibawah ini adalah fungsi statis untuk memanggil base64 decode dengan data type return String plaintext

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private static String decodeData(String e) {     try {         return new String(Base64.getDecoder().decode(e.getBytes()));     } catch (Exception ex) {         return e;     } }} }

Simpan script java dibawah ini dengan nama HelloWorld.java

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import java.util.Base64;   class HelloWorld {           private static String encodeData(String e) {         try {             return new String(Base64.getEncoder().encode(e.getBytes()));         } catch (Exception ex) {             return e;         }     }           private static String decodeData(String e) {         try {             return new String(Base64.getDecoder().decode(e.getBytes()));         } catch (Exception ex) {             return e;         }     }         public static void main(String[] args) {         String mytext = "hello world java";                   String encoded_string = encodeData(mytext);         System.out.println("base64 encoded text : "+encoded_string+"\n");                   String decoded_string = decodeData(encoded_string);         System.out.println("base64 decoded text : "+decoded_string+"\n");     } }

Jalankan script java : java HelloWorld.java, hasilnya:

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base64 encoded text : aGVsbG8gd29ybGQgamF2YQ==   base64 decoded text : hello world java

Java switch select statement

Simpan script java dengan nama HelloWorld.java

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class HelloWorld {     public static void main(String[] args) {         String animal = "dog";         switch(animal){             case "dog":                 System.out.println("found animal dog");                 break;             case "cat":                 System.out.println("found animal cat");                 break;             case "bird":                 System.out.println("found animal bird");                 break;             default:                 break;         }     } }

Jalankan script java : java HelloWorld.java, hasilnya:

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1	found animal dog