A leap year is a year containing one additional day (366 days a year). Review the leap year algorithm : if year is divisible by 400 then is_leap_year else if year is divisible by 100 then not_leap_year else if year is divisible by 4 then is_leap_year else not_leap_year P.S Algorithm from wikipedia leap year. 1. […]
Two Java examples show you how to print the elapsed time in days, hours, minutes and seconds format. 1. Standard JDK Date APIs You need to calculate the elapsed time manually. DateTimeUtils.java package com.mkyong.dateUtils; import java.text.ParseException; import java.text.SimpleDateFormat; import java.util.Date; public class DateTimeUtils { public static void main(String[] args) { DateTimeUtils obj = new DateTimeUtils(); […]
In Mongodb, you can use sort()to do the date sorting. 1. MongoDB Sorting Examples In Mongodb, to sort a “date” field, issues : //The ‘1’ = sort ascending (oldest to newest) db.domain.find().sort({lastModifiedDate:1}) { "_id" : 1, "lastModifiedDate" : ISODate("2013-08-13T07:18:04.774Z") } { "_id" : 2, "lastModifiedDate" : ISODate("2013-09-03T08:12:16.309Z") } { "_id" : 3, "lastModifiedDate" : ISODate("2013-10-03T08:12:16.309Z") […]
In SQL, the ‘like’ query is looks like this : select * from tags where tagName like ‘%apple%’ In MongoDB console, it looks like this : db.tags.find({"tagName": /apple/}) In Spring data mongodb, it implements with Criteria or BasicQuery : String tagName = "apple"; Query query = new Query(); query.limit(10); query.addCriteria(Criteria.where("tagName").regex(tagName)); mongoOperation.find(query, Tags.class); String tagName = […]
Review a simple jQuery example to loop over a JavaScript array object. var json = [ {"id":"1","tagName":"apple"}, {"id":"2","tagName":"orange"}, {"id":"3","tagName":"banana"}, {"id":"4","tagName":"watermelon"}, {"id":"5","tagName":"pineapple"} ]; $.each(json, function(idx, obj) { alert(obj.tagName); }); Above code snippet is working fine, prompts the “apple”, “orange” … as expected. Problem : JSON string Review below example, declares a JSON string (enclosed with single […]
There is no direct way to iterate over a Java List with jQuery, see the following case study : Spring controller @RequestMapping(value = "/", method = RequestMethod.GET) public ModelAndView getPages() { List<String> list = new ArrayList<String>(); list.add("List A"); list.add("List B"); list.add("List C"); list.add("List D"); list.add("List E"); ModelAndView model = new ModelAndView("somepage"); model.addObject("list", list); return model; […]
Below is a JSON string. JSON String { "name": "mkyong", "age": 30, "address": { "streetAddress": "88 8nd Street", "city": "New York" }, "phoneNumber": [ { "type": "home", "number": "111 111-1111" }, { "type": "fax", "number": "222 222-2222" } ] } To access the JSON object in JavaScript, parse it with JSON.parse(), and access it via […]
In this tutorial, we show you how to find a location using an IP address, with the following technologies : Spring MVC frameworks. jQuery (Ajax Request). GeoLite database. Google Map. Review the tutorial’s flows A page with a text input and button. Type an IP address, and clicks on the button. jQuery fires an Ajax […]
In this example, we show you how to find a location (country, city, latitude, longitude) using an IP address. 1. GeoLite Database The MaxMind provides a free GeoLite database (IP Address to Location). Get a free GeoLite free Databases – here Get a GeoIP client Java APIs – here Start code it. 2. GeoLite Java […]
There are many ways the favicon can be recognized by the web browser : Example 1 <head> <link rel="icon" href="http://example.com/image.ico" /> </head> Example 2 <head> <link rel="icon" href="http://example.com/image.png" /> </head> Example 3 – weird, but Google use it. <head> <meta content="/images/google_favicon_128.png" itemprop="image" /> </head> 1. Jsoup Example Code snippets to get above favicon with Jsoup. […]
In this tutorial, we show you how to do exception handling in Spring MVC frameworks. Normally, we use @ExceptionHandler to decide which “view” should be returned back if certain exception is raised. P.S This @ExceptionHandler class is available since Spring 3.0 1. Project Structure Review the project directory structure, a standard Maven project. 2. Custom […]
In this tutorial, we show you how to print the List values via JSTL c:forEach tag. P.S This web project is using Spring MVC frameworks v3.2 1. Project Structure Review the project directory structure, a standard Maven project. 2. Project Dependencies Add Spring and JSTL libraries. pom.xml <properties> <spring.version>3.2.2.RELEASE</spring.version> <jstl.version>1.2</jstl.version> </properties> <dependencies> <!– jstl –> […]
In this article, we show you 2 examples to join two lists in Java. JDK – List.addAll() Apache Common – ListUtils.union() 1. List.addAll() example Just combine two lists with List.addAll(). JoinListsExample.java package com.mkyong.example; import java.util.ArrayList; import java.util.List; public class JoinListsExample { public static void main(String[] args) { List<String> listA = new ArrayList<String>(); listA.add("A"); List<String> listB […]
Below code snippet shows you how to execute a JavaScript in Selenium WebDriver. WebDriver driver = new ChromeDriver(); if (driver instanceof JavascriptExecutor) { ((JavascriptExecutor) driver).executeScript("alert(‘hello world’);"); } 1. WebDriver Example In this example, it uses WebDriver to load “google.com”, and executes a simple alert () later. JavaScriptExample.java package com.mkyong.test; import org.openqa.selenium.JavascriptExecutor; import org.openqa.selenium.WebDriver; import org.openqa.selenium.chrome.ChromeDriver; […]
By default, the “.” doesn’t match line breaks. To match multiple lines, add (?s) prefix or enable the Pattern.DOTALL flag. 1. Example A address sample, we need to extract the “Address 1” only. Starting… Address 1: 88 app 2/8 superman taman, puchong 36100, Malaysia Address 2: abc End Failed : To extract “Address 1”, this […]
The Selenium WebDriver is closed, but the “chromedriver.exe” process is left hanging in the system. See figure : Problem Here is the code, a simple WebDriver example to load a URL and exists, but the chromedriver.exe never get killed. LoadWebPageExample.java package com.mkyong.test; import org.openqa.selenium.WebDriver; import org.openqa.selenium.chrome.ChromeDriver; import org.openqa.selenium.chrome.ChromeOptions; import org.openqa.selenium.remote.DesiredCapabilities; public class LoadWebPageExample { public […]
In Java, by default, the regular expression (regex) matching is case sensitive. To enable the regex case insensitive matching, add (?) prefix or enable the case insensitive flag directly in the Pattern.compile(). A regex pattern example. Pattern = Registrar:\\s(.*) Case Insensitive, add (?) prefix. Pattern = (?)Registrar:\\s(.*) Case Insensitive, add Pattern.CASE_INSENSITIVE flag. Pattern.compile("Registrar:\\s(.*)", Pattern.CASE_INSENSITIVE); 1. […]
A simple example to use Jackson to convert a JSON string to a Map. String json = "{name:\"mkyong\"}"; Map<String,String> map = new HashMap<String,String>(); ObjectMapper mapper = new ObjectMapper(); map = mapper.readValue(json, new TypeReference<HashMap<String,String>>(){}); Problem When the program is executed, it hits following error message org.codehaus.jackson.JsonParseException: Unexpected character (‘n’ (code 110)): was expecting double-quote to start […]
A desktop computer, Windows 8 is installed, connect to a nearby router via a wireless USB adapter. D-Link DWA-132 – Wireless N USB Adapter D-Link Wireless N300 Router DIR-615 Fiber optic internet If the computer is idle sometime, it will interval drops the wifi connection, and reconnect it again. The desktop computer was installed Windows […]
Developing a simple Java program to write a file in the C drive root directory (where Windows is installed), but the program prompts an “access is denied” error. Try to create an empty file in the C drive root directory manually, but no options to create any files, only new folder is allowed. P.S The […]
Spring Batch tutorials with full example, including itemReader, itemProcessor, itemWriter, Tasklet, Listener, unit test, scheduler, partitioning and etc.
In this tutorial, we will show you how to use the Quartz scheduler framework to schedule a Spring batch job to run every 10 seconds. Tools and libraries used Maven 3 Eclipse 4.2 JDK 1.6 Spring Core 3.2.2.RELEASE Spring Batch 2.2.0.RELEASE Quartz 1.8.6 The relationship looks like the following : Spring Batch <–> Spring QuartzJobBean […]
Spring Batch is a framework for batch processing – execution of a series of jobs. In Spring Batch, A job consists of many steps and each step consists of a READ-PROCESS-WRITE task or single operation task (tasklet). For “READ-PROCESS-WRITE” process, it means “read” data from the resources (csv, xml or database), “process” it and “write” […]
In this tutorial, we will show you how to use Spring TaskScheduler to schedule a batch job to run every 5 seconds. Tools and libraries used Maven 3 Eclipse 4.2 JDK 1.6 Spring Core 3.2.2.RELEASE Spring Batch 2.2.0.RELEASE 1. Project Directory Structure A standard Maven project. 2. Spring TaskScheduler Spring 3.0 introduces a TaskScheduler for […]
Photo Credit : Spring Source In Spring Batch, “Partitioning” is “multiple threads to process a range of data each”. For example, assume you have 100 records in a table, which has “primary id” assigned from 1 to 100, and you want to process the entire 100 records. Normally, the process starts from 1 to 100, […]
In this tutorial, we will show you how to read data from a MySQL database, with JdbcCursorItemReader and JdbcPagingItemReader, and write it into an XML file. Tools and libraries used Maven 3 Eclipse 4.2 JDK 1.6 Spring Core 3.2.2.RELEASE Spring OXM 3.2.2.RELEASE Spring Batch 2.2.0.RELEASE MySQL Java Driver 5.1.25 P.S This example – MySQL jdbc […]
In Spring batch, there are six “listeners” to intercept the step execution, I believe the class name should be self-explanatory. StepExecutionListener ItemReadListener ItemProcessListener ItemWriteListener ChunkListener SkipListener 1. Listener Example Three listener examples, do nothing but print out a message. CustomStepListener.java package com.mkyong.listeners; import org.springframework.batch.core.ExitStatus; import org.springframework.batch.core.StepExecution; import org.springframework.batch.core.StepExecutionListener; public class CustomStepListener implements StepExecutionListener { @Override […]
In Spring batch, the Tasklet is an interface, which will be called to perform a single task only, like clean or set up resources before or after any step execution. In this example, we will show you how to use Tasklet to clean up the resource (folders) after a batch job is completed. P.S The […]
In this tutorial, we will show you how to read items from multiple resources (multiple csv files), and write the items into a single csv file. Tools and libraries used Maven 3 Eclipse 4.2 JDK 1.6 Spring Core 3.2.2.RELEASE Spring Batch 2.2.0.RELEASE P.S This example – 3 CSV files (reader) – combine into a single […]
A quick guide to show you how to run a Spring batch job with CommandLineJobRunner. 1. Spring Batch Job Example A simple job. resources/spring/batch/jobs/job-read-files.xml <?xml version="1.0" encoding="UTF-8"?> <beans … <import resource="../config/context.xml"/> <job id="readJob" xmlns="http://www.springframework.org/schema/batch"> <step id="step1"> <tasklet> <chunk reader="flatFileItemReader" writer="flatFileItemWriter" commit-interval="1" /> </tasklet> </step> </job> <!– … –> </beans> 2. Package Project Use Maven to […]
Domain Name Regular Expression Pattern ^((?!-)[A-Za-z0-9-]{1,63}(?<!-)\\.)+[A-Za-z]{2,6}$ Above pattern makes sure domain name matches the following criteria : The domain name should be a-z | A-Z | 0-9 and hyphen(-) The domain name should between 1 and 63 characters long Last Tld must be at least two characters, and a maximum of 6 characters The domain […]
Read following Spring batch job, it reads data from “domain.csv“, and map it to a domain object. job-example.xml <bean class="org.springframework.batch.item.file.FlatFileItemReader" > <property name="resource" value="file:outputs/csv/domain.csv" /> <property name="lineMapper"> <bean class="org.springframework.batch.item.file.mapping.DefaultLineMapper"> <property name="lineTokenizer"> <bean class="org.springframework.batch.item.file.transform.DelimitedLineTokenizer"> <property name="names" value="id, domainName, lastModifiedDate" /> </bean> </property> <property name="fieldSetMapper"> <bean class="org.springframework.batch.item.file.mapping.BeanWrapperFieldSetMapper"> <property name="prototypeBeanName" value="domain" /> </bean> </property> </bean> </property> </bean> <bean […]
A quick guide to show you how to add @Copyright comment to new and existing Java files in Eclipse IDE. Solution 1. Eclipse Code Templates Go to preferences -> Java -> Code Style -> Code Templates, expands Code and select “New Java Files”, edit the template to add whatever copyright messages you want. Now, that […]
Create a simple Spring batch job to write data to a csv file. The csv file name depends on the pass in job’s parameters, interprets by Spring EL . job-sample.xml <bean id="csvFileItemWriter" class="org.springframework.batch.item.file.FlatFileItemWriter"> <!– write to this csv file –> <property name="resource" value="file:outputs/csv/domain.done.#{jobParameters[‘pid’]}.csv" /> <property name="appendAllowed" value="false" /> <property name="lineAggregator"> <bean class="org.springframework.batch.item.file.transform.DelimitedLineAggregator"> <property name="delimiter" value="," […]
In Eclipse IDE, you can type CTRL + SHIFT + T in Windows or *nix or Command + SHIFT + T in Mac OSX to prompt an Open Type dialog box to find details about a specified Java class. For example, if you want to know the detail of this Java class – FlatFileItemWriter (Spring […]
In this tutorial, we will show you how to configure a Spring Batch job to read XML file (JAXB2 library) into a csv file, and filter out the record before writing with ItemProcessor. Tools and libraries used Maven 3 Eclipse 4.2 JDK 1.6 Spring Core 3.2.2.RELEASE Spring Batch 2.2.0.RELEASE Spring OXM 3.2.2.RELEASE P.S This example […]
In this tutorial, we will show you how to configure a Spring Batch job to read data from an XML file (XStream library) into a no SQL database (MongoDB). In additional, create a unit test case to launch and test the batch jobs. Tools and libraries used Maven 3 Eclipse 4.2 JDK 1.6 Spring Core […]
Following the official Spring batch unit testing guide to create a standard unit test case. @RunWith(SpringJUnit4ClassRunner.class) @ContextConfiguration(locations = { "classpath:spring/batch/jobs/job-abc.xml", "classpath:spring/batch/config/context.xml"}) public class AppTest { @Autowired private JobLauncherTestUtils jobLauncherTestUtils; @Test public void launchJob() throws Exception { JobExecution jobExecution = jobLauncherTestUtils.launchJob(); assertEquals(BatchStatus.COMPLETED, jobExecution.getStatus()); } } P.S spring-batch-test.jar is added to the classpath. Problem When launches above […]
In this tutorial, we will show you how to unit test Spring batch jobs with jUnit and TestNG frameworks. To unit test batch job, declares spring-batch-test.jar, @autowired the JobLauncherTestUtils, launch the job or step, and assert the execution status. 1. Unit Test Dependencies To unit test Spring batch, declares following dependencies : pom.xml <!– Spring […]
In this tutorial, we will show you how to convert a String to java.util.Date. Many Java beginners are stuck in the Date conversion, hope this summary guide will helps you in some ways. // String -> Date SimpleDateFormat.parse(String); // Date -> String SimpleDateFormat.format(date); Refer to table below for some of the common date and time […]
