Collage

java

Encoding / Decoding as Base64 in Java

package com.bad.blood.test; import java.security.InvalidKeyException; import java.security.Key; import java.util.Base64; import javax.crypto.BadPaddingException; import javax.crypto.Cipher; import javax.crypto.IllegalBlockSizeException; import javax.crypto.KeyGenerator; public class LocalEncrypter { private static String algorithm = "DESede"; private static Key key = null; private static Cipher cipher = null; private static void setUp() throws Exception { key = KeyGenerator.getInstance( algorithm ).generateKey(); cipher = Cipher.getInstance( algorithm ); } public static void main(String [] args) throws Exception { setUp(); byte [] encryptionBytes = null; String input = "phenomena"; System.out.println( "Entered: " + input ); encryptionBytes = encrypt( input ); String encodeString = new String(Base64.getEncoder().encode(encryptionBytes)); System.out.println( "Base64 Encode: " + encodeString ); System.out.println( "Recovered: " + decrypt( Base64.getDecoder().decode(encodeString) ) ); } private static byte [] encrypt(String input) throws InvalidKeyException, BadPaddingException, IllegalBlockSizeException { cipher.init( Cipher.ENCRYPT_MODE, key ); byte [] inputBytes = input.getBytes(); return cipher.doFinal(inputBytes); } private static String decrypt(byte [] encryptionBytes) throws InvalidKeyException, BadPaddingException, IllegalBlockSizeException { cipher.init( Cipher.DECRYPT_MODE, key ); byte [] recoveredBytes = cipher.doFinal( encryptionBytes ); String recovered = new String( recoveredBytes ); return recovered; } } result: Entered: phenomena Base64 Encode: lfE0CaaNbx1sGUJk6dwgjQ== Recovered: phenomena ref. https://stackoverflow.com/questions/13109588/encoding-as-base64-in-java * Image to Base64 String Conversion package com.bad.blood.test; import java.io.File; import java.io.IOException; import java.util.Base64; import org.apache.commons.io.FileUtils; import org.junit.jupiter.api.Test; import static org.junit.Assert.assertTrue; public class FileToBase64StringConversionUnitTest { private String inputFilePath = "test_image.jpg"; private String outputFilePath = "test_image_copy.jpg"; @Test public void fileToBase64StringConversion() throws IOException { // load file from /src/test/resources ClassLoader classLoader = getClass().getClassLoader(); File inputFile = new File(classLoader .getResource(inputFilePath) .getFile()); byte[] fileContent = FileUtils.readFileToByteArray(inputFile); String encodedString = Base64 .getEncoder() .encodeToString(fileContent); // create output file File outputFile = new File(inputFile .getParentFile() .getAbsolutePath() + File.pathSeparator + outputFilePath); // decode the string and write to file byte[] decodedBytes = Base64 .getDecoder() .decode(encodedString); FileUtils.writeByteArrayToFile(outputFile, decodedBytes); assertTrue(FileUtils.contentEquals(inputFile, outputFile)); } } ref. https://www.baeldung.com/java-base64-image-string

John Doe · Jan. 16, 2023, 8:06 a.m.

base64 encode decode

java

Play with JSoup

Removing Html tags except few specific ones from String in java public String clean(String unsafe){ Whitelist whitelist = Whitelist.none(); whitelist.addTags(new String[]{"p","br","ul"}); String safe = Jsoup.clean(unsafe, whitelist); return StringEscapeUtils.unescapeXml(safe); } For input string String unsafe = "paragraph< this is not html > <a link='#'>Link</a> <![CDATA[<sender>John Smith</sender>]]>"; I get following output which is pretty much I require. paragraph< this is not html > Link <sender>John Smith</sender>

John Doe · Jan. 14, 2023, 2:24 a.m.

jsoup

python

Django migrate gets error "table already exists"

1. Remove all migration files in <appname>/migrations 2. Remove all data in django_migrations table where app = <appname> 3. python manage.py makemigrations <appname> 4. python manage.py migrate --fake <appname> 5. If you have a field to alter, then alter the field <field> on <appname> and then again python manage.py makemigrations <appname> 6. python manage.py migrate <appname> Child's play. 0003이 실제로 적용된 가장 최근의 마이그레이션이라 가정할 때에는? --fake를 이용하여 현재 상태는 0003이다 라고 장고가 인식하게끔 해주어야 한다. python manage.py migrate --fake <appname> 0003 그 후 평소 하던대로 진행. django 1.7 migrate gets error "table already exists" I am trying to apply a migration but am getting the error: django.db.utils.OperationalError: (1050, "Table 'customers_customer' already exists") I get this by issuing the following command: ... https://stackoverflow.com/questions/25924858/django-1-7-migrate-gets-error-table-already-exists How to redo a migration on django 1.8 after using --fake Something went wrong on my migrations, I added a new datetimefield to a model then I used makemigrations and migrate. python manage.py makemigrations python manage.py migrate But after this the m... https://stackoverflow.com/questions/30626886/how-to-redo-a-migration-on-django-1-8-after-using-fake

John Doe · Jan. 12, 2023, 9:59 p.m.

django migration

server

How to change where a symlink points

files is a symbolic link to /media/files/tb-prod/files. When you access files or anything inside it, you'll really access the path under /media. Symbolic links are made and updated using the ln command. This link could have been made with: ln -s /media/files/tb-prod/files files -s means to make a symbolic link. To update a link, either delete the link and create it as above, or use the -f option to ln as well. If you are linking to a folder, you should include the -n option: ln -sfn /a/new/path files This will replace the link with a new one pointing at /a/new/path. The -n option is necessary when linking to a different target folder to avoid creating a sub-folder inside that symbolic link and instead replace the symbolic link completely. e.g. contact@me:/mnt/webdav$ ls a1 a2 a3 a4 a5 a6 contact@me:/mnt/webdav$ ln -sfn /mnt/a2/XYZ a2 contact@me:/mnt/webdav$ ls a1 a2 a3 a4 a5 a6 contact@me:/mnt/webdav$ https://unix.stackexchange.com/questions/151999/how-to-change-where-a-symlink-points

John Doe · Jan. 12, 2023, 9:08 a.m.

Ubuntu linux

server

ubuntu 하드디스크 마운트

John Doe · Jan. 12, 2023, 8:19 a.m.

Ubuntu mount

server

우분투 서버에 삼바(SAMBA) 설치 및 설정

1. 삼바설치 sudo apt-get -y update sudo apt-get -y install samba 2. 기존에 사용하고 있는 리눅스 계정을 Samba에 추가하기 위해 아래 명령어를 입력 sudo smbpasswd -a <계정명> 계정은 리눅스에 존재하는 계정이면 Samba에 계속 추가할 수 있음 3. 원본을 보존하기 위해 Samba 설정 파일을 백업 sudo cp /etc/samba/smb.conf /etc/samba/smb.conf_temp 4. Samba 설정 파일을 수정 sudo nano /etc/samba/smb.conf 5. 공유할 디렉토리를 설정하기 위해서 설정 파일의 가장 하단에 아래와 같은 형태로 입력 [multimedia] comment = multimedia directory path = /data/Multimedia valid users = id1,id2 writeable = yes read only = no create mode = 0777 directory mode = 0777 6. 파일 수정이 완료되면 저장하고 Samba 데몬을 재시작 sudo service smbd restart 위의 명령어로 삼바 데몬을 재 구동을 시켜주면 좀전에 설정한 내역들이 적용됨. * 파이썬으로 삼바접속 1. pysmb 라이브러리 설치 (https://pypi.org/project/pysmb/) 2. 예제코드 from smb.SMBConnection import SMBConnection server_ip = "10.110.10.10" # Take your server IP - I have put a fake IP :) server_name = 'myserver' # The servername for the IP above share_name = "GRUPOS" # This is the principal folder of your network that you want's to connect network_username = 'myuser' # This is your network username network_password = '***' # This is your network password machine_name = 'myuser@mac-mc70006405' # Your machine name conn = SMBConnection(network_username, network_password, machine_name, server_name, use_ntlm_v2 = True) assert conn.connect(server_ip, 139) files = conn.listPath(share_name, "/TECNOLOGIA_INFORMACAO/Dashboard Diretoria/") for item in files: print(item.filename) https://psychoria.tistory.com/678 리눅스 환경(Ubuntu)에서 개발을 편리하게! Samba 구축하기 - 코드도사 (codedosa.com) How to get a file from a network windows directory and move to my Python Django project directory? - Stack Overflow

John Doe · Jan. 12, 2023, 7:27 a.m.

Ubuntu samba

python

Fix SSL error when install packages using pip

Q : pip install fails with "connection error: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:598)" A : pip install gensim config --global http.sslVerify false Just install any package with the "config --global http.sslVerify false" statement You can ignore SSL errors by setting pypi.org and files.pythonhosted.org as well as the older pypi.python.org as trusted hosts. $ pip install --trusted-host pypi.org --trusted-host pypi.python.org --trusted-host files.pythonhosted.org <package_name> Note: Sometime during April 2018, the Python Package Index was migrated from pypi.python.org to pypi.org. This means "trusted-host" commands using the old domain no longer work, but you can add both. Permanent Fix Since the release of pip 10.0, you should be able to fix this permanently just by upgrading pip itself: $ pip install --trusted-host pypi.org --trusted-host pypi.python.org --trusted-host files.pythonhosted.org pip setuptools Or by just reinstalling it to get the latest version: $ curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py (… and then running get-pip.py with the relevant Python interpreter). pip install <otherpackage> should just work after this. If not, then you will need to do more, as explained below. You may want to add the trusted hosts and proxy to your config file. pip.ini (Windows) or pip.conf (unix) [global] trusted-host = pypi.python.org pypi.org files.pythonhosted.org Alternate Solutions (Less secure) Most of the answers could pose a security issue. Two of the workarounds that help in installing most of the python packages with ease would be: Using easy_install: if you are really lazy and don't want to waste much time, use easy_install <package_name>. Note that some packages won't be found or will give small errors. Using Wheel: download the Wheel of the python package and use the pip command pip install wheel_package_name.whl to install the package. https://stackoverflow.com/questions/25981703/pip-install-fails-with-connection-error-ssl-certificate-verify-failed-certi/26062583

John Doe · Jan. 12, 2023, 3:28 a.m.

ssl pip

java

Java Regular Expression

Removing everything but numbers from String String value = string.replaceAll("[^0-9]",""); String clean1 = string1.replaceAll("[^0-9]", ""); or String clean2 = string2.replaceAll("[^\\d]", ""); Where \d is a shortcut to [0-9] character class, or String clean3 = string1.replaceAll("\\D", ""); Where \D is a negation of the \d class (which means [^0-9]) Using Match, Pattern class in java.util.regex boolean bln = Pattern.matches("^[a-zA-Z0-9]*$", this.input); ^ : 문자열의 시작 $ : 문자열의 종료 . : 임의의 한 문자(문자의 종류는 가리지 않음) | : or ? : 앞 문자가 없거나 하나있음. + : 앞 문자가 하나 이상임. * : 앞 문자가 없을 수도 무한정 많을 수도 있음을 나타냄. 만약, .* 으로 정규식이 시작한다면 시작하는 문자열과 같은 문자열이 뒤에 없거나 많을 수도 있는 경우에만 일치를 시킨다. 즉, abc 일 경우 시작문자인 a를 기준으로 a가 없을경우와 a가 무한정 많은 경우에도 true를 반환하기 때문에 abc의 경우는 true를 반환한다. [] : 문자 클래스를 지정할 때 사용. 문자의 집합이나 범위를 나타내면 두 문자 사이는 '-' 기호로 범위를 나타낸다. []내에서 ^ 가 선행하여 나타나면 not를 나타낸다. {} : 선행문자가 나타나는 횟수 또는 범위 a{3} 인 경우 a가 3번 반복된 경우 / a{3,}이면 a가 3번 이상 반복인 경우. 또한 a{3,5}인 경우 a가 3번 이상 5번 이하 반복된 경우를 나타냄 \w : 알파벳이나 숫자 \W : 알파벳이나 숫자를 제외한 문자 \d : 숫자 [0-9]와 동일 \D : 숫자를 제외한 모든 문자 ^[0-9]*$ : only number ^[a-zA-Z]*$ : only English ^[가-힣]*$ : only Korean ^[a-zA-Z0-9]*$ : English/number e.g. 1) email : ^[a-zA-Z0-9]+@[a-zA-Z0-9]+$ or ^[_0-9a-zA-Z-]+@[0-9a-zA-Z-]+(.[_0-9a-zA-Z-]+)*$ cellphone : ^01(?:0|1|[6-9]) - (?:\d{3}|\d{4}) - \d{4}$ phone : ^\d{2,3} - \d{3,4} - \d{4}$ id : \d{6} \- [1-4]\d{6} IP addr : ([0-9]{1,3}) \. ([0-9]{1,3}) \. ([0-9]{1,3}) \. ([0-9]{1,3}) https://stackoverflow.com/questions/6883579/java-regular-expression-removing-everything-but-numbers-from-string 2) How to test if a String contains both letters and numbers .matches("^(?=.*[A-Z])(?=.*[0-9])[A-Z0-9]+$") The regex asserts that there is an uppercase alphabetical character (?=.*[A-Z]) somewhere in the string, and asserts that there is a digit (?=.*[0-9]) somewhere in the string, and then it checks whether everything is either alphabetical character or digit. 3) How can I de-duplicate repeated characters in a Java string? how________are_______you to how_are_you string.replaceAll("_+", "_")

John Doe · Jan. 12, 2023, 2:56 a.m.

regex

java

How do I create a screen capture using Robot class?

In this example you’ll see how to create a screen capture / screenshot and save it as an image file such a PNG image. Some classes are use in this program including the java.awt.Robot, java.awt.image.BufferedImage and javax.imageio.ImageIO. package org.kodejava.awt; import javax.imageio.ImageIO; import java.awt.image.BufferedImage; import java.awt.AWTException; import java.awt.Dimension; import java.awt.Rectangle; import java.awt.Robot; import java.io.File; import java.io.IOException; public class ScreenCapture { public static void main(String[] args) { try { Robot robot = new Robot(); // Capture screen from the top left in 200 by 200 pixel size. BufferedImage bufferedImage = robot.createScreenCapture( new Rectangle(new Dimension(200, 200))); // The captured image will the written into a file called // screenshot.png File imageFile = new File("screenshot.png"); ImageIO.write(bufferedImage, "png", imageFile); } catch (AWTException | IOException e) { e.printStackTrace(); } } } https://kodejava.org/how-do-i-create-a-screen-capture-using-robot-class/

John Doe · Jan. 12, 2023, 2:44 a.m.

BufferedImage ImageIO Robot

java

Simple Q&A

Q : Where can I download JSTL taglibs? i.e. jstl.jar and standard.jar A : If you're running a Servlet 2.5 compatible container and the web.xml is declared as at least Servlet 2.5, then you should be able to use the new JSTL 1.2 instead. Note that JSTL 1.2 does not require a standard.jar. Q : The superclass "javax.servlet.http.HttpServlet" was not found on the Java Build Path A : Add a runtime first and select project properties. Then check the server name from the 'Runtimes' tab Q : Remove html tags from string using java A : String noHTMLString = htmlString.replaceAll("\\<.*?>",""); Using Jsoup public static String html2text(String html) { return Jsoup.parse(html).text(); } https://stackoverflow.com/questions/4432560/remove-html-tags-from-string-using-java Q : JSPX A : https://jspx-bay.sourceforge.net/ Q : Apache Jakarta A : http://archive.apache.org/dist/jakarta/ Q : Prevent download attempts of videos in a video server A : Silverlight might be an idea to start with. Q : mp3 header information reader not working A : import org.farng.mp3.MP3File; you need to call mp3file.seekMP3Frame(); before attempting to retrieve bitrate, this method will read the file headers including the bitrate. or use http://www.jthink.net/jaudiotagger/examples_id3.jsp Q : How to get the message in a custom error page (Tomcat)? A : <c:out value="${requestScope['javax.servlet.error.message']}"/> javax.servlet.error.status_code java.lang.Integer javax.servlet.error.exception_type java.lang.Class javax.servlet.error.message java.lang.String javax.servlet.error.exception java.lang.Throwable javax.servlet.error.request_uri java.lang.String javax.servlet.error.servlet_name java.lang.String * <c:catch> Tag <%@ taglib uri = "http://java.sun.com/jsp/jstl/core" prefix = "c" %> <html> <head> <title><c:catch> Tag Example</title> </head> <body> <c:catch var ="catchException"> <% int x = 5/0;%> </c:catch> <c:if test = "${catchException != null}"> The exception is : ${catchException} There is an exception: ${catchException.message} </c:if> </body> </html> Q : Get current action in jsp - struts2 A : <s:url forceAddSchemeHostAndPort="true" includeParams="all"/> Q : Oracle date to Java date A : little h for "Hour in am/pm (1-12)" and H for "Hour in day (0-23)" see here: SimpleDateFormat SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.S"); Date date = dateFormat.parse("2011-08-19 06:11:03.0"); Q : How to get previous URL? A : HttpServletRequest.getHeader("Referer"); Q : [JSP] 파일 다운로드창에서 한글깨짐 방지? A : response.setHeader("Content-Disposition", "attachment; filename=" + URLEncoder.encode(fileName, "utf-8") + ";");

John Doe · Jan. 12, 2023, 2:03 a.m.

java

How to Display Row Header on JTable Instead of Column Header

John Doe · Jan. 12, 2023, 1:36 a.m.

JTable swing

java

How do you return a JSON object from a Java Servlet

Write the JSON object to the response object's output stream. You should also set the content type as follows, which will specify what you are returning: response.setContentType("application/json"); // Get the printwriter object from response to write the required json object to the output stream PrintWriter out = response.getWriter(); // Assuming your json object is **jsonObject**, perform the following, it will return your json object out.print(jsonObject); out.flush(); or First convert the JSON object to String. Then just write it out to the response writer along with content type of application/json and character encoding of UTF-8. Here's an example assuming you're using Google Gson to convert a Java object to a JSON string: protected void doXxx(HttpServletRequest request, HttpServletResponse response) { // ... String json = new Gson().toJson(someObject); response.setContentType("application/json"); response.setCharacterEncoding("UTF-8"); response.getWriter().write(json); } That's all. https://stackoverflow.com/questions/2010990/how-do-you-return-a-json-object-from-a-java-servlet

John Doe · Jan. 12, 2023, 1:30 a.m.

Department

programming

programming

Encoding / Decoding as Base64 in Java

Play with JSoup

Django migrate gets error "table already exists"

How to change where a symlink points

ubuntu 하드디스크 마운트

우분투 서버에 삼바(SAMBA) 설치 및 설정

Fix SSL error when install packages using pip

Java Regular Expression

How do I create a screen capture using Robot class?

Simple Q&A

How to Display Row Header on JTable Instead of Column Header

How do you return a JSON object from a Java Servlet

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