In this tutorial, we will show you a Spring MVC + Mustache JS template web application example. Technologies used : Spring 4.2.4.RELEASE mustache.js JDK 1.8.0_66 Jackson 2.7 Eclipse 4.3 Tomcat 8 Maven 3 Bootstrap 3 Note This solution is still working, but recommend this simple Spring Boot + JMustache solution. In Spring, we can use […]
Start a Java webapp with Maven Jetty plugin. $ mvn jetty:run 1. Problem But it hits the following error messages : [WARNING] FAILED org.eclipse.jetty.maven.plugin.JettyServer@1f53481b: java.net.BindException: Address already in use at sun.nio.ch.Net.bind0(Native Method) at sun.nio.ch.Net.bind(Net.java:433) at sun.nio.ch.Net.bind(Net.java:425) at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:223) at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:74) at org.eclipse.jetty.server.ServerConnector.open(ServerConnector.java:321) at org.eclipse.jetty.server.AbstractNetworkConnector.doStart(AbstractNetworkConnector.java:80) //… 2. Solution By default, the maven-jetty-plugin start Jetty on port […]
Always, Java developers need to know which application is using the high demand 8080 port. In this tutorial, we will show you two ways to find out which application is using port 8080 on Linux. 1. lsof + ps command 1.1 Bring up the terminal, type lsof -i :8080 $ lsof -i :8080 COMMAND PID […]
Review a jQuery Ajax form submit. $(document).ready(function () { $("#hostingForm").submit(function (e) { e.preventDefault(e); var data = {} data["id"] = $("#id").val(); data["domain"] = $("#domain").val(); data["name"] = $("#name").val(); //… $.ajax({ type: "POST", contentType: "application/json", url: "{{home}}/hosting/update", data: JSON.stringify(data), dataType: ‘json’, timeout: 600000, success: function (data) { console.log("SUCCESS: ", data); }, error: function (e) { console.log("ERROR: ", e); […]
To view the request or response HTTP headers in Google Chrome, take the following steps : In Chrome, visit a URL, right click, select Inspect to open the developer tools. Select Network tab. Reload the page, select any HTTP request on the left panel, and the HTTP headers will be displayed on the right panel.
By default, Meteor app start on port 3000 $ meteor [[[[[ ~/path-to/meteor/hello ]]]]] => Started proxy. => Started MongoDB. => Started your app. => App running at: http://localhost:3000/ 1. Meteor Port 9999 To start Meteor app on a different port, start Meteor with –port parameter. $ meteor –port 9999 [[[[[ ~/path-to/meteor/app ]]]]] => Started proxy. […]
Review the below @PathVariable example. @RequestMapping("/site") public class SiteController { @RequestMapping(value = "/{q}", method = RequestMethod.GET) public ModelAndView display(@PathVariable("q") String q) { return getModelAndView(q, "site"); } } See the following cases : For input /site/google, q = google For input /site/google.com, q = google where is the .com? For input /site/google.com.my, q = google.com For […]
In this tutorial, we will show you how to create a website with Meteor framework. Tools used : Meteor 1.2.1 Tested with Linux (Debian, Ubuntu or Mint) Tested with Mac OSX 1. Install Meteor Issue curl https://install.meteor.com | sh, everything will be installed and configured. $ curl https://install.meteor.com | sh % Total % Received % […]
Few examples to show you how to split a String into a List in Python. 1. Split by whitespace By default, split() takes whitespace as the delimiter. alphabet = "a b c d e f g" data = alphabet.split() #split string into a list for temp in data: print temp Output a b c d […]
In this tutorial, we will show you how to use for-in-loop to loop a List in Python. #example 1 frameworks = [‘flask’, ‘pyramid’, ‘django’] #list for temp in frameworks: print temp print "Python framework : %s" %temp #example 2 numbers = [2,4,6,8,10] #list for num in numbers: print num print "Number : %d" %num Output […]
Reviewing a jQuery Ajax form POST and Spring MVC example, find out the following patterns : <script> jQuery(document).ready( function($) { $("#btn-save").click(function(event) { var id = $(‘#id’).val(); var domain = $(‘#domain’).val(); var name = $(‘#name’).val(); var desc = $(‘#desc’).val(); var tags = $(‘#tags’).val(); var afflink = $(‘#afflink’).val(); var cdn = $("#cdn").prop("checked") ? true : false; var […]
Spring doesn’t allow to inject value into static variables, for example: import org.springframework.beans.factory.annotation.Value; import org.springframework.stereotype.Component; @Component public class GlobalValue { @Value("${mongodb.db}") public static String DATABASE; } If you print out the GlobalValue.DATABASE, a null will be displayed. GlobalValue.DATABASE = null Solution To fix it, create a “none static setter” to assign the injected value for […]
In this tutorial, we will show you how to install Oracle JDK 8 On Debian, manually. Environment : Debian 7 OpenJDK 1.7 is installed. (Switch to Oracle JDK 8 later) At the time of writing, OpenJDK 1.8 is not included in the default apt-get repository yet. I just don’t like the default apt repository schedule, […]
In this tutorial, we will show you how to install Apache Tomcat 8 On Debian, manually. Environment : Debian 7 JDK 1.8 Apache Tomcat 8 P.S Assume the JDK 1.8 is installed in /opt/jdk folder. Refer to this guide to install Oracle JDK 8 on Debian. Note On Debian 7, the Tomcat 8 is not […]
In Java 8, you can use Files.lines to read file as Stream. c://lines.txt – A simple text file for testing line1 line2 line3 line4 line5 1. Java 8 Read File + Stream TestReadFile.java package com.mkyong.java8; import java.io.IOException; import java.nio.file.Files; import java.nio.file.Paths; import java.util.stream.Stream; public class TestReadFile { public static void main(String args[]) { String fileName […]
In Java, the System.getenv() returns an unmodifiable string Map view of the current system environment. Map<String, String> env = System.getenv(); // get PATH environment variable String path = System.getenv("PATH"); Table of contents. 1. Get a specified environment variable 2. UnsupportedOperationException 3. Display all environment variables 4. Sort the environment variables 5. Download Source Code 6. […]
In this tutorial, we will show you how to use Jackson 2.x to convert Java objects to / from a JSON. 1. Basic 1.1 Convert a Staff object to from JSON. writeValue(…) – Java Objects to JSON ObjectMapper mapper = new ObjectMapper(); // Java object to JSON file mapper.writeValue(new File("c:\\test\\staff.json"), new Staff()); // Java object […]
In this tutorial, we will show you how to create a Spring MVC web project and submit a form via Ajax. Technologies used : Spring 4.2.2.RELEASE Jackson 2.6.3 Logback 1.1.3 jQuery 1.10.2 Maven 3 JDK 1.8 Tomcat 8 or Jetty 9 Eclipse 4.5 Boostrap 3 P.S If the Jackson library is found in the project […]
Performs a large sort operation (Aggregation) in a collection, and hits the following error message : MongoDB Console > db.bigdata.aggregate( {$group : {_id : "$range", total : { $sum : 1 }}}, {$sort : {total : -1}} ); #… aggregate failed at Error (<anonymous>) at doassert (src/mongo/shell/assert.js:11:14) #… Error: command failed: { "errmsg" : "exception: […]
In Java, we can use String#split() to split a string. String phone = "012-3456789"; // String#split(string regex) accepts regex as the argument String[] output = phone.split("-"); String part1 = output[0]; // 012 String part2 = output[1]; // 3456789 Table of contents 1. Split a string (default) 2. Split a string and retain the delimiter 3. […]
In Java, we can use TimeUnit.SECONDS.sleep() or Thread.sleep() to delay few seconds. 1. TimeUnit JavaDelayExample.java package com.mkyong; import java.util.Date; import java.util.concurrent.TimeUnit; public class JavaDelayExample { public static void main(String[] args) { try { System.out.println("Start…" + new Date()); // delay 5 seconds TimeUnit.SECONDS.sleep(5); System.out.println("End…" + new Date()); // delay 0.5 second //TimeUnit.MICROSECONDS.sleep(500); // delay 1 minute […]
In Python, you can use time.sleep(seconds) to make the current executing Python program to sleep or delay a few seconds. import time time.sleep(1) # delays for 1 seconds time.sleep(10) # delays for 10 seconds time.sleep(60) # delays for 1 minute time.sleep(3600) # delays for 1 hour Full example. test_delay.py import time def main(): while True: […]
In this tutorial, we will show you how to loop a dictionary in Python. 1. for key in dict: 1.1 To loop all the keys from a dictionary – for k in dict: for k in dict: print(k) 1.2 To loop every key and value from a dictionary – for k, v in dict.items(): for […]
In Java, you can use Map.containsKey() to check if a key exists in a Map. TestMap.java package com.mkyong.examples; import java.util.HashMap; import java.util.Map; public class TestMap { public static void main(String[] args) { Map<String, Integer> fruits = new HashMap<>(); fruits.put("apple", 1); fruits.put("orange", 2); fruits.put("banana", 3); fruits.put("watermelon", null); System.out.println("1. Is key ‘apple’ exists?"); if (fruits.containsKey("apple")) { //key […]
In this article, we will show you how to create a simple Whois client both in Python 2 and Python 3. Tested Python 2.7.10 Python 3.4.3 1. Python 3 Whois example In Python 3, the socket accepts bytes, so you need to encode() and decode() manually. whois3.py import sys import socket s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) […]
On Debian, type cat /etc/debian_version to display the Debian version. Terminal $ cat /etc/debian_version 9.5 Alternatively, cat /etc/issue Terminal $ cat /etc/issue Debian GNU/Linux 9 \n \l The last one, lsb-release -a, it will display the Debian detail. Terminal $ lsb-release -a -bash: lsb-release: command not found $ sudo apt-get install lsb-release $ lsb_release -a […]
In Python, you can use the in operator to check if a key exists in a dictionary. test.py def main(): fruits = { ‘apple’:1, ‘orange’:2, ‘banana’:3 } #if key ‘apple’ exists in fruits? if ‘apple’ in fruits: print(fruits[‘apple’]) if __name__ == ‘__main__’: main() Output 1 P.S Tested with Python 3.4.3 Note has_key() is deprecated in […]
Learn how to set the JAVA_HOME environment variable on Windows 10 or 11 with easy-to-follow steps and screenshots.
In Java 8, we can use the new forEach to loop or iterate a Map, List, Set, or Stream. Topics Loop a Map Loop a List forEach and Consumer forEach and Exception handling forEach vs forEachOrdered 1. Loop a Map 1.1 Below is a normal way to loop a Map. public static void loopMapClassic() { […]
In this article, we will show you three ways to generate random integers in a range. java.util.Random.nextInt Math.random java.util.Random.ints (Java 8) 1. java.util.Random This Random().nextInt(int bound) generates a random integer from 0 (inclusive) to bound (exclusive). 1.1 Code snippet. For getRandomNumberInRange(5, 10), this will generates a random integer between 5 (inclusive) and 10 (inclusive). private […]
In this example, we will show you how to use Java 8 Lambda expression to write a Comparator to sort a List. 1. Classic Comparator example. Comparator<Developer> byName = new Comparator<Developer>() { @Override public int compare(Developer o1, Developer o2) { return o1.getName().compareTo(o2.getName()); } }; 2. Lambda expression equivalent. Comparator<Developer> byName = (Developer o1, Developer o2)->o1.getName().compareTo(o2.getName()); […]
Just upgraded to Java 8, and the Tomcat 7 keeps prompting the following exceptions: Jul 20, 2015 4:06:36 PM org.apache.catalina.startup.ContextConfig processAnnotationsJar SEVERE: Unable to process Jar entry [jdk/nashorn/internal/objects/NativeURIError.class] from Jar [jar:file:/Library/Java/JavaVirtualMachines/jdk1.8.0_45.jdk/Contents/Home/jre/lib/ext/nashorn.jar!/] for annotations org.apache.tomcat.util.bcel.classfile.ClassFormatException: Invalid byte tag in constant pool: 15 at org.apache.tomcat.util.bcel.classfile.Constant.readConstant(Constant.java:131) at org.apache.tomcat.util.bcel.classfile.ConstantPool.<init>(ConstantPool.java:60) at org.apache.tomcat.util.bcel.classfile.ClassParser.readConstantPool(ClassParser.java:209) at org.apache.tomcat.util.bcel.classfile.ClassParser.parse(ClassParser.java:119) at org.apache.catalina.startup.ContextConfig.processAnnotationsStream(ContextConfig.java:2066) at org.apache.catalina.startup.ContextConfig.processAnnotationsJar(ContextConfig.java:1942) at org.apache.catalina.startup.ContextConfig.processAnnotationsUrl(ContextConfig.java:1908) […]
Review a Python 2 socket example whois.py import sys import socket s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.connect(("whois.arin.net", 43)) s.send(sys.argv[1] + "\r\n") #Python 2.7 send signature #socket.send(string[, flags]) If compile with Python 3, it prompts the following error? Traceback (most recent call last): File "C:\repos\hc\whois\python\whois.py", line 6, in <module> s.send(sys.argv[1] + "\r\n") TypeError: ‘str’ does not support […]
In HSQLDB you can use IDENTITY keyword to define an auto-increment column, normally, this is the primary key. Review below examples : 1. IDENTITY – Default By default, the IDENTITY value is start with zero. CREATE TABLE users ( id INTEGER IDENTITY PRIMARY KEY, name VARCHAR(30), email VARCHAR(50) ); INSERT INTO users (name, email) VALUES […]
Here’s the scenario, the controller returns a ModelAndView, and an exception is thrown while rendering the JSP view page, reason behind is one of message code is not found. org.apache.jasper.JasperException: org.springframework.context.NoSuchMessageException: No message found under code ‘Diff.userform.password’ for locale ‘en_US’. org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:549) org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:470) org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390) org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334) javax.servlet.http.HttpServlet.service(HttpServlet.java:722) An exception is thrown and render an HTTP 500 error […]
In a nutshell, a servlet filter lets you intercepts requests and responses on your web application. This article shows you how to register a servlet filter in Spring XML and JavaConfig. 1. Servlet Filter Review the following custom filter, it will catch any exceptions and redirect to an error page. package com.mkyong.form.web; import java.io.IOException; import […]
Spring examples to show you how to mix both Spring XML and JavaConfig together. 1. Load JavaConfig From Spring XML A Spring MVC example, uses @Configuration to load everything, and you want integrate with web.xml SpringWebConfig.java package com.mkyong.form.config; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.ComponentScan; import org.springframework.context.annotation.Configuration; import org.springframework.web.servlet.config.annotation.EnableWebMvc; import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry; import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter; import org.springframework.web.servlet.view.InternalResourceViewResolver; import org.springframework.web.servlet.view.JstlView; @EnableWebMvc […]
In this article, we will show you how to validate the submitted form values with Spring validator and Hibernate Validator (bean validation). Technologies used : Spring 4.1.6.RELEASE Hibernate Validator 5.1.3.Final 1. Hibernate Validator The Hibernate validator will be fired if @Valid is provided. import org.hibernate.validator.constraints.NotEmpty; public class User { @NotEmpty String name; //… } @RequestMapping(value […]
In this article, we will show you few Spring form tag examples to check if a field has an error message. Review the following Spring MVC bean validation example : Technologies used : Spring 4 JSTL 1.2 //Bean validation import org.hibernate.validator.constraints.NotEmpty; public class User { @NotEmpty String name; //… } //Controller class @RequestMapping(value = "/users", […]
Converting a Python 2 socket example to Python 3 whois.py import sys import socket s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.connect(("whois.arin.net", 43)) s.send((sys.argv[1] + "\r\n").encode()) response = "" while True: data = s.recv(4096) response += data if not data: break s.close() print(response) If compile with Python 3, it prompts the following error? Traceback (most recent call last): […]
