In this tutorial, we will show you how to use Maven to manage a Multi-module project containing four modules : Password module – Interface only. Password md5 module – Password module implementation, MD5 password hashing. Password sha module – Password module implementation, SHA password hashing. Web module – A simple MVC web app to hash […]
Review the following jUnit 5 examples to test a Spring 5 MVC web application. TestWelcome.java package com.mkyong.web; import com.mkyong.web.config.SpringConfig; import org.junit.jupiter.api.BeforeEach; import org.junit.jupiter.api.Test; import org.junit.jupiter.api.extension.ExtendWith; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.test.context.ContextConfiguration; import org.springframework.test.context.junit.jupiter.SpringExtension; import org.springframework.test.context.web.WebAppConfiguration; import org.springframework.test.web.servlet.MockMvc; import org.springframework.test.web.servlet.setup.MockMvcBuilders; import org.springframework.web.context.WebApplicationContext; import static org.junit.jupiter.api.Assertions.assertEquals; import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get; import static org.springframework.test.web.servlet.result.MockMvcResultHandlers.print; import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.*; @ExtendWith(SpringExtension.class) @WebAppConfiguration @ContextConfiguration(classes = […]
The Apache Maven Eclipse Plugin is retired, no more following commands # support eclipse ide $ mvn eclipse:eclipse # web project $ mvn eclipse:eclipse -Dwtpversion=2.0 What is the equivalent in Eclipse IDE? 1. Solution Please use Eclipse Maven Integration (m2e). Latest Eclipse IDE has bundled the m2e plugin : 2. How to use m2e? The […]
Maven compile a project in Eclipse IDE, but hits the following error messages : $ mvn clean compile [ERROR] COMPILATION ERROR : [INFO] ————————————————————- [ERROR] No compiler is provided in this environment. Perhaps you are running on a JRE rather than a JDK? [INFO] 1 error [INFO] ————————————————————- [INFO] ———————————————————————— [INFO] BUILD FAILURE [INFO] ———————————————————————— […]
In Java, we can convert the BigInteger to a String object and get the length of the String. JavaExample.java package com.mkyong; import java.math.BigInteger; public class JavaExample { public static void main(String[] args) { BigInteger bigInteger = BigInteger.valueOf(100000000000000000L); //18 System.out.println(bigInteger.toString().length()); } } Output 18 References BigInteger JavaDoc Quora – What are the limits of String Size […]
In Java, you can use the Security.getAlgorithms(“MessageDigest”) to list all the available MessageDigest algorithms. ListMessageDigest.java package com.mkyong.hashing; import java.security.Security; import java.util.Set; public class ListMessageDigest { public static void main(String[] args) { Set<String> messageDigest = Security.getAlgorithms("MessageDigest"); messageDigest.forEach(x -> System.out.println(x)); } } Output SHA3-512 SHA-384 SHA SHA3-384 SHA-224 SHA-512/256 SHA-256 MD2 SHA-512/224 SHA3-256 SHA-512 MD5 SHA3-224 P.S […]
This article shows you a few ways to convert byte arrays or byte[] to a hexadecimal (base 16 or hex) string representative. String.format Integer.toHexString Apache Commons Codec – commons-codec Spring Security Crypto – spring-security-crypto Bitwise shifting and masking. (educational purposes) Note Both Apache Commons-Codec and Spring Security Crypto modules are using the similar 5. Bitwise […]
In Maven, you can use mvn help:effective-pom to list all the current project’s plugins and its version. D:\maven-examples\java-web-project> mvn help:effective-pom [INFO] Scanning for projects… [INFO] [INFO] ——————< com.mkyong.web:java-web-project >——————- [INFO] Building java-web-project Maven Webapp 1.0-SNAPSHOT [INFO] ——————————–[ war ]——————————— [INFO] [INFO] — maven-help-plugin:3.1.0:effective-pom (default-cli) @ java-web-project — [INFO] Effective POMs, after inheritance, interpolation, and profiles […]
In Java, we can use String.join(“,”, list) to join a List String with commas. 1. Java 8 1.1 String.join JavaStringExample1.java package com.mkyong; import java.util.Arrays; import java.util.List; public class JavaStringExample1 { public static void main(String[] args) { List<String> list = Arrays.asList("a","b","c"); String result = String.join(",", list); System.out.println(result); } } Output a,b,c 1.2 Stream Collectors.joining JavaStringExample2.java package […]
In Python, we can use len() to count the number of items in a List list = ["a", "b", "c"] print(len(list)) Output 3 References Pyhton docs – len()
In Python, we can use in operator or str.find() to check if a String contains another String. 1. in operator name = "mkyong is learning python 123" if "python" in name: print("found python!") else: print("nothing") Output found python! 2. str.find() name = "mkyong is learning python 123" if name.find("python") != -1: print("found python!") else: print("nothing") […]
In Python, we can use os.path.isfile() or pathlib.Path.is_file() (Python 3.4) to check if a file exists. 1. pathlib New in Python 3.4 from pathlib import Path fname = Path("c:\\test\\abc.txt") print(fname.exists()) # true print(fname.is_file()) # true print(fname.is_dir()) # false dir = Path("c:\\test\\") print(dir.exists()) # true print(dir.is_file()) # false print(dir.is_dir()) # true If check from pathlib import […]
We can just divide the nanoTime by 1_000_000_000, or use the TimeUnit.SECONDS.convert to convert it. Note 1 second = 1_000_000_000 nanosecond JavaExample.java package com.mkyong; import java.util.concurrent.TimeUnit; public class JavaExample { public static void main(String[] args) throws InterruptedException { long start = System.nanoTime(); Thread.sleep(5000); long end = System.nanoTime(); long elapsedTime = end – start; System.out.println(elapsedTime); // […]
In Python, we can use a global keyword to referring a global variable. 1. Review the below example : a = 10 def updateGlobal(): a = 5 updateGlobal() print(a) # 10 Output – It will return a 10, instead of 5. 10 2. To modify the global variable “a”, add a global keyword like this […]
In Python, we can use float() to convert String to float. num = "3.1415" print(num) print(type(num)) # str pi = float(num) # convert str to float print(pi) print(type(pi)) # float Output 3.1415 <class ‘str’> 3.1415 <class ‘float’> References Python docs – float()
In Python, we can use str() to convert a int to String. num1 = 100 print(type(num1)) # <class ‘int’> num2 = str(num1) print(type(num2)) # <class ‘str’> Output <class ‘int’> <class ‘str’> References Python docs – str() Python – How to convert String to int
In Python, we can use type() to check the variable’s type. num = "3.141592653589793238" print(type(num)) pi = float(num) print(type(pi)) Output <class ‘str’> <class ‘float’> References Python docs – type()
In Python, we can use int() to convert a String to int. # String num1 = "88" # <class ‘str’> print(type(num1)) # int num2 = int(num1) # <class ‘int’> print(type(num2)) 1. Example A Python example to add two numbers. 1.1 Add two String directly. num1 = "1" num2 = "2" num3 = num1 + num2 […]
In Java, we can use List.size() to count the number of items in a List package com.mkyong.example; import java.util.Arrays; import java.util.List; public class JavaExample { public static void main(String[] args) { List<String> list = Arrays.asList("a", "b", "c"); System.out.println(list.size()); } } Output 3 References Java doc – List
In Python, we can use str() to convert float to String. pi = 3.1415 print(type(pi)) # float piInString = str(pi) # float -> str print(type(piInString)) # str Output <class ‘float’> <class ‘str’> References Python docs – str() Python – How to convert int to String Python – How to convert String to float
In the terminal, we can type mysql -V (uppercase V) to display the current MySQL version installed on the server. Terminal $ mysql -V mysql Ver 8.0.18 for Linux on x86_64 (MySQL Community Server – GPL) The above output show MySQL version 8.0.18 is installed on the server. Server System Variables Alternatively, we can connect […]
Selection sort is an in-place comparison sort. It loops and find the first smallest value, swaps it with the first element; loop and find the second smallest value again, swaps it with the second element, repeats third, fourth, fifth smallest values and swaps it, until everything is in correct order. P.S Selection sort is inefficient […]
Bubble sort is the simplest sorting algorithm, it compares the first two elements, if the first is greater than the second, swaps them, continues doing (compares and swaps) for the next pair of adjacent elements. It then starts again with the first two elements, compares, swaps until no more swaps are required. 1. Explanation #unsorted […]
In Kotlin, you can loop a Map via the following ways: 1. for loop val items = HashMap<String, Int>() items["A"] = 10 items["B"] = 20 for ((k, v) in items) { println("$k = $v") } 2. forEach items.forEach { k, v -> println("$k = $v") } 1. For Loop Loop a Map and filter it […]
In IDEA, you can type sout and press Tab to generate System.out.println automatically. Tips : To show all shortcuts, press CTRL + J References Intellij IDEA – Code completion Intellij IDEA – default static void main shortcut
In IDEA, you can type psvm and press Tab to generate the public static void main(String[] args) automatically. To show all shortcuts, press CTRL + J References Intellij IDEA – Code completion Intellij IDEA – System.out.println shortcut
Try to log into the MySQL server, but it prompts the following error message: Terminal $ mysql ERROR 1045 (28000): Access denied for user ‘root’@’localhost’ (using password: NO) 1. Solution – (using password: NO) The user ‘root’ need a password to log into the MySQL server. To solve it, please provide a password with -p […]
Fresh installs a WordPress on Windows for development, and hits the ERR_TOO_MANY_REDIRECTS error message? Tested URL : http://localhost/index.php/wp-admin/install.php Tested : PHP 7.1.10 WordPress 4.8.3 Nginx 1.12.1 MySQL 5.7.17 Windows 10 your-nginx\conf\nginx.conf upstream php { server 127.0.0.1:9999; } server { listen 80; server_name localhost; root www/wordpress; location / { try_files $uri $uri/ /index.php?$args; } location ~ […]
Install WordPress and hits the following error message : Fatal error: Uncaught Error: Call to undefined function mysql_connect() in C:\nginx-1.12.1\www\wordpress\wp-includes\wp-db.php… Tested PHP 7.1.10 WordPress 4.8.3 Nginx 1.12.1 MySQL 5.7.17 Windows 10 Solution To install WordPress, PHP needs Mysql extension, to fix this, loads php_mysqli.dll in php.ini file. php.ini ; Directory in which the loadable extensions […]
This article shows you how to install and integrate Nginx and PHP on Windows. Tested Nginx 1.12.1 PHP 7.1.10 Windows 10 1. Install Nginx + PHP Basically, just download zip file and extracts it, no installation. To install Nginx Visit http://nginx.org/en/download.html Download nginx/Windows-1.12.2 Extract to C:\nginx-1.12.1 To Install PHP Visit http://windows.php.net/download/ Download PHP7.1 download VC14 […]
Run php-cgi.exe and hits a pop up dialog showing the following error message : Application Error : The application was unable to start correctly (0xc000007b) Terminal c:\php7.1>php-cgi.exe -b 127.0.0.1:9123 Tested with PHP 7.1.10 on Windows 10 Solution To run PHP on Windows, you need to install Redistributable for Visual Studio, refer to the official PHP […]
A common Nginx + PHP error message “No input file specified.” nginx.conf http { include mime.types; default_type application/octet-stream; server { listen 80; server_name localhost; location / { root www; index index.html index.htm; } location ~ \.php$ { fastcgi_pass 127.0.0.1:9999; fastcgi_index index.php; fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name; include fastcgi_params; } } } Tested with Nginx 1.12.1 + PHP […]
Technology: Primefaces it’s java based web framework to develop web applications using java. It’s one of the compliance frameworks for JSF, there are many other frameworks like omnifaces, richfaces. Primefaces has rich UI components. In this tutorial primefaces, maven, java8, glasifish servers are used. Use case: If you want to open a new page by […]
Here we will create a Spring Boot web application example with Hibernate Search + Thymeleaf template engine, and deploy it as a WAR to Wildfly 10.1. Technologies used: Spring Boot 1.5.6.RELEASE Java 8 Hibernate Search 5.6.1.Final Embedded Tomcat, Wildfly 8.1 Final & 10.1 Final 1. Project Structure A standard Maven project structure 1. Project Dependencies […]
Here is the .htaccess file. /Library/WebServer/Documents/.htaccess # BEGIN WordPress <IfModule mod_rewrite.c> RewriteEngine On RewriteBase /mkyong/ RewriteRule ^index\.php$ – [L] RewriteCond %{REQUEST_FILENAME} !-f RewriteCond %{REQUEST_FILENAME} !-d RewriteRule . /mkyong/index.php [L] </IfModule> # END WordPress Solution Find the Apache config file in /etc/apache2/httpd.conf, make sure the following settings are configured properly : 1. The mod_rewrite.so is loaded. […]
On Mac OSX, the default localhost folder is located at /Library/WebServer/Documents P.S Tested with MacOS Sierra, 10.12.6 Find httpd.conf By default, Apache is enabled and installed in /etc/apache2/, inside httpd.conf file, find DocumentRoot to tell where is the default localhost folder. sudo vim /etc/apache2/httpd.conf # DocumentRoot: The directory out of which you will serve your […]
This article will help you to understand how to create a user defined function. It’s also known as stored function or user function. User defined functions are similar to procedures. The only difference is that function always returns a value. User defined functions can be used as a part of an SQL expression. Note Oracle […]
The BITAND function treats its inputs and its output as vectors of bits, the output is the bitwise AND of the inputs. Basically it performs below steps. Converts the inputs into binary. Performs a standard bitwise AND operation on these two strings. Converts the binary result back into decimal and returns the value. 1. BITAND […]
Git clone a new project, Gradle build and hits the following error message : Terminal $ gradle clean build FAILURE: Build failed with an exception. * Where: Build file ‘/Users/mkyong/Documents/workspace/hc2/web/build.gradle’ line: 25 * What went wrong: A problem occurred evaluating project ‘:web’. > Could not find method compileOnly() for arguments [org.springframework.boot:spring-boot-starter-tomcat] on project ‘:web’. * […]
Default, MongoDB creates the log file at this path /var/log/mongodb/mongodb.log, if the log file is not found, please check with the MongoDB config file. logpath Check the MongoDB config file at /etc/mongod.conf or /yourMongoDBpath/mongod.conf, the logpath defined where to log. /etc/mongod.conf $ cat /etc/mongod.conf # mongod.conf # Where to store the data. # Note: if […]
