form表单加密前台js后台java

1.前台javascript
	1.在提交的js中这样写
		<!-- 加密解密 -->
		document.form1.username.value=encode64(document.form1.username.value);
		document.form1.password.value=encode64(document.form1.password.value);
			
		document.form1.submit();
	2.加密js这样写
		<!-- base64加密开始-->
		var keyStr = "ABCDEFGHIJKLMNOP" +"QRSTUVWXYZabcdef" +"ghijklmnopqrstuv" +"wxyz0123456789+/" + "=";
		
		function encode64(input) {
		
			 var output = "";
			 var chr1, chr2, chr3 = "";
			 var enc1, enc2, enc3, enc4 = "";
			 var i = 0;
			 do
			 {
				 chr1 = input.charCodeAt(i++);
				 chr2 = input.charCodeAt(i++);
				 chr3 = input.charCodeAt(i++);
				 enc1 = chr1 >> 2;
				 enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
				 enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
				 enc4 = chr3 & 63;
				 if (isNaN(chr2)){
					 enc3 = enc4 = 64;
				 }else if (isNaN(chr3)){
					 enc4 = 64;
				 }
				 output = output +
				 keyStr.charAt(enc1) +
				 keyStr.charAt(enc2) +
				 keyStr.charAt(enc3) +
				 keyStr.charAt(enc4);
				 chr1 = chr2 = chr3 = "";
				 enc1 = enc2 = enc3 = enc4 = "";
			 } while (i < input.length);
			 
			 return output;
		   
		}	
		<!-- base64加密结束-->

2.后台java代码这样写，比如
	
	private static char[] base64EncodeChars = new char[] {    
		 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
		 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
		 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
		 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
		 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
		 'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
		 'w', 'x', 'y', 'z', '0', '1', '2', '3',
		 '4', '5', '6', '7', '8', '9', '+', '/',};    
	   
	   private static byte[] base64DecodeChars = new byte[] {    
	   -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,    
	   -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,    
	   -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63,    
	   52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1,    
	   -1,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,    
	   15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,    
	   -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,    
	   41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1 };    
    
	   public static byte[] decode(String str) {    
	       byte[] data = str.getBytes();    
	       int len = data.length;    
	       ByteArrayOutputStream buf = new ByteArrayOutputStream(len);
	       int i = 0;    
	       int b1, b2, b3, b4;    
	    
	       while (i < len) {     
	           do {    
	               b1 = base64DecodeChars[data[i++]];    
	           } while (i < len && b1 == -1);    
	           if (b1 == -1) {    
	               break;    
	           }    
	              
	           do {    
	               b2 = base64DecodeChars[data[i++]];    
	           } while (i < len && b2 == -1);    
	           if (b2 == -1) {    
	               break;    
	           }    
	           buf.write((int) ((b1 << 2) | ((b2 & 0x30) >>> 4)));    
	               
	           do {    
	               b3 = data[i++];    
	               if (b3 == 61) {    
	                   return buf.toByteArray();    
	               }    
	               b3 = base64DecodeChars[b3];    
	           } while (i < len && b3 == -1);    
	           if (b3 == -1) {    
	               break;    
	           }    
	           buf.write((int) (((b2 & 0x0f) << 4) | ((b3 & 0x3c) >>> 2)));    
	               
	           do {    
	               b4 = data[i++];    
	               if (b4 == 61) {    
	                   return buf.toByteArray();    
	               }    
	               b4 = base64DecodeChars[b4];    
	           } while (i < len && b4 == -1);    
	           if (b4 == -1) {    
	               break;    
	           }    
	           buf.write((int) (((b3 & 0x03) << 6) | b4));    
	       }    
	       return buf.toByteArray();    
	   }

	   2.解密示例：
		public final String getUsername() {
			//logger.info( "解密前的用户名是 : " + this.username );
			decodeusername = decode(this.username);
			String decodeuser = new String(decodeusername);
			//logger.info( "解密后的用户名是 : " + decodeuser );
			return decodeuser;
		    }

		public final String getPassword() {
			
			//logger.info( "解密前密码是  : " + this.password );
			decodepassword = decode(this.password);
			String decodepass = new String(decodepassword);
			//logger.info( "解密后密码是  : " + decodepass );
			return decodepass;
		    }