In Spring MVC application, comes with few “LocaleResolver” to support the internationalization or multiple languages features. In this tutorial, it shows a simple welcome page, display the message from properties file, and change the locale based on the selected language link. 1. Project Folder Directory structure of this example. 2. Properties file Two properties files […]
Problem In Spring MVC application, while changing the locale with “org.springframework.web.servlet.i18n.LocaleChangeInterceptor“, it hits the following error java.lang.UnsupportedOperationException: Cannot change HTTP accept header – use a different locale resolution strategy …AcceptHeaderLocaleResolver.setLocale(AcceptHeaderLocaleResolver.java:45) Solution In Spring MVC application, if you do not configure the Spring’s LocaleResolver, it will use the default AcceptHeaderLocaleResolver, which does not allow to change […]
In this tutorial, we will show you how to use the log4j framework to do the logging in a Spring MVC web application. Technologies and tools used : Log4j 1.2.17 Spring 4.1.6.RELEASE Maven 3 Tomcat 6 Eclipse Kepler 4.3 Note By default, Spring (spring-core) is using the JCL (commons-logging) for logging, and the JCL has […]
Spring MVC allow you to intercept web request through handler interceptors. The handler interceptor have to implement the HandlerInterceptor interface, which contains three methods : preHandle() – Called before the handler execution, returns a boolean value, “true” : continue the handler execution chain; “false”, stop the execution chain and return it. postHandle() – Called after […]
Often times, you may mix use of multiple handler mappings strategy in Spring MVC development. For example, use ControllerClassNameHandlerMapping to map all the convention handler mappings, and SimpleUrlHandlerMapping to map other special handler mappings explicitly. <beans …> <bean class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping"> <property name="mappings"> <value> /index.htm=welcomeController /welcome.htm=welcomeController /main.htm=welcomeController /home.htm=welcomeController </value> </property> <property name="order" value="0" /> </bean> <bean class="org.springframework.web.servlet.mvc.support.ControllerClassNameHandlerMapping" […]
In Spring MVC application, the SimpleUrlHandlerMapping is the most flexible handler mapping class, which allow developer to specify the mapping of URL pattern and handlers explicitly. The SimpleUrlHandlerMapping can be declared in two ways. 1. Method 1 – prop key The property keys are the URL patterns while the property values are the handler IDs […]
In Spring MVC, ControllerClassNameHandlerMapping use convention to map requested URL to Controller (convention over configuration). It takes the Class name, remove the ‘Controller’ suffix if exists and return the remaining text, lower-cased and with a leading “/”. See following few examples to demonstrate the use of this ControllerClassNameHandlerMapping class. 1. Before and After By default, […]
In Spring MVC, BeanNameUrlHandlerMapping is the default handler mapping mechanism, which maps URL requests to the name of the beans. For example, <beans …> <bean class="org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping"/> <bean name="/welcome.htm" class="com.mkyong.common.controller.WelcomeController" /> <bean name="/streetName.htm" class="com.mkyong.common.controller.StreetNameController" /> <bean name="/process*.htm" class="com.mkyong.common.controller.ProcessController" /> </beans> In above example, If URI pattern /welcome.htm is requested, DispatcherServlet will forward the request to the […]
This tutorial shows you how to create a Spring Web MVC application with the Thymeleaf template. Technologies and tools used: Java 11 Spring 5.2.22.RELEASE Thymeleaf 3.0.15.RELEASE Embedded Jetty Server 9.4.45.v20220203 Servlet API 4.0.4 Bootstrap 5.2.0 (webjars) IntelliJ IDEA Maven 3.8.6 Spring Test 5.2.22.RELEASE Hamcrest 2.2 JUnit 5.9 Table of contents: 1. Spring Web MVC Basic […]
Problem In Spring MVC development, developer try to set a value into a model, and display the value in JSP via EL, e.g ${msg}, but it just outputs the result as it is – ${msg}, not the “value” stored in the model. The EL is just not working in JSP, why? Spring’s Controller import javax.servlet.http.HttpServletRequest; […]
The standard.jar (taglib) library is used to enable the JSTL expression language in JSP page, and it’s always used together with the jstl.jar together. <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %> <html> …. </html> To download both standard.jar and jstl.jar from Maven, just put the following Maven coordinate in the pom.xml file. <!– standard.jar –> <dependency> <groupId>taglibs</groupId> […]
Here’s the best 20 Java websites in my collections, which provides latest Java news, articles and tutorials. If you have other great Java websites, please leave a comment to share with others. P.S The order doesn’t means any priority. 1. O’Reilly Java URL : http://www.onjava.com Since : 10-feb-2000 Rss : http://www.oreillynet.com/pub/feed/7?format=rss2 Description : O’Reilly’s, contains […]
In this tutorial, it shows the use of java.lang.Comparable and java.util.Comparator to sort a Java object based on its property value. 1. Sort an Array To sort an Array, use the Arrays.sort(). String[] fruits = new String[] {"Pineapple","Apple", "Orange", "Banana"}; Arrays.sort(fruits); int i=0; for(String temp: fruits){ System.out.println("fruits " + ++i + " : " + […]
Java example to show the use of Arrays.sort() to sort an Array. The code should be self-explanatory. import java.util.Arrays; import java.util.Collections; public class ArraySorting{ public static void main(String args[]){ String[] unsortStringArray = new String[] {"c", "b", "a", "3", "2", "1"}; int[] unsortIntArray = new int[] {7,5,4,6,1,2,3}; System.out.println("Before sort"); System.out.println("— unsortStringArray —"); for(String temp: unsortStringArray){ System.out.println(temp); […]
By default, the ArrayList’s elements are display according to the sequence it is put inside. Often times, you may need to sort the ArrayList to make it alphabetically order. In this example, it shows the use of Collections.sort(‘List’) to sort an ArrayList. import java.util.ArrayList; import java.util.Collections; import java.util.List; public class SortArrayList{ public static void main(String […]
Few Java examples to sort a Map by its keys or values. Note If you are using Java 8, refer to this article – How to use Stream APIs to sort a Map 1. Sort by Key 1.1 Uses java.util.TreeMap, it will sort the Map by keys automatically. SortByKeyExample1.java package com.mkyong.test; import java.util.HashMap; import java.util.Map; […]
Here’s a few ways to initialize an java.util.ArrayList, see the following full example: InitArrayList.java package com.mkyong.examples; import java.util.ArrayList; import java.util.Arrays; import java.util.List; public class InitArrayList { public static void main(String[] args) { //1. Normal way List<String> list = new ArrayList<String>(); list.add("String A"); list.add("String B"); list.add("String C"); System.out.println("List 1……"); for (String temp : list) { System.out.println(temp); […]
This article show few ways of loop Map in Java. 1. Using entrySet() 2. Using forEach (Java 8 and later) 3. Using stream() (Java 8 and later) 4. Using iterator() 5. Using keySet() and get() 6. References 1. Using `entrySet()` Before Java 8, this is the most common method to loop a Map in Java. […]
Problem A very strange and rare problem, happened in JPA or Hibernate development. Caused by: java.lang.ClassFormatError: Absent Code attribute in method that is not native or abstract in class file javax/persistence/GenerationType at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClassCond(Unknown Source) at java.lang.ClassLoader.defineClass(Unknown Source) at java.security.SecureClassLoader.defineClass(Unknown Source) at java.net.URLClassLoader.defineClass(Unknown Source) at java.net.URLClassLoader.access$000(Unknown Source) at java.net.URLClassLoader$1.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) […]
Problem In JPA or Hibernate development, it hits the following error message : Caused by: java.lang.ClassNotFoundException: javax.transaction.TransactionManager at java.net.URLClassLoader$1.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) … 23 more Solution The javax.transaction.TransactionManager is a class inside the J2EE SDK library “javaee.jar“, you are missing this jar […]
Problem In JPA or Hibernate development, it hits the following error message : Caused by: java.lang.ClassNotFoundException: javax.persistence.Entity at java.net.URLClassLoader$1.run(Unknown Source) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source) at java.lang.ClassLoader.loadClass(Unknown Source) … 24 more Solution The javax.persistence.Entity is a class inside the J2EE SDK library “javaee.jar“, you are missing this jar […]
In the Terminal, we can use `javac -version` to check the installed JDK version and `java -version` to check the installed JRE version.
Problem In Hibernate development, it’s common to hits the following error message. SEVERE: Context initialization failed org.springframework.beans.factory.BeanCreationException: Error creating bean with name ‘sessionFactory’ defined in ServletContext resource [/WEB-INF/classes/config/database/spring/HibernateSessionFactory.xml]: Invocation of init method failed; nested exception is Caused by: org.hibernate.HibernateException: Unable to instantiate default tuplizer [org.hibernate.tuple.entity.PojoEntityTuplizer] … … Caused by: java.lang.reflect.InvocationTargetException at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown […]
In Java, we can use the Java 1.7 FileVisitor or Apache Commons IO FileUtils.copyDirectory to copy a directory, which includes its sub-directories and files. This article shows a few of the common ways to copy a directory in Java. FileVisitor (Java 7+) FileUtils.copyDirectory (Apache commons-io) Custom Copy using Java 7 NIO and Java 8 Stream. […]
Problem Recently, i have installed an Aptana plugins in Eclipse IDE, after that , when i pressed “ctrl + space” in a Struts 2 xml file, the content assist is not working anymore. See picture : The content assist is not suggesting any Struts 2 elements, even the Struts 2 dtd is included correctly in […]
Here’s an example to check if a directory is empty. Example package com.mkyong.file; import java.io.File; public class CheckEmptyDirectoryExample { public static void main(String[] args) { File file = new File("C:\\folder"); if(file.isDirectory()){ if(file.list().length>0){ System.out.println("Directory is not empty!"); }else{ System.out.println("Directory is empty!"); } }else{ System.out.println("This is not a directory"); } } }
If we use the NIO Files.delete to delete a non-empty directory in Java, it throws DirectoryNotEmptyException; for legacy IO File.delete to delete a non-empty directory, it returns a false. The standard solution is to loop the directory recursively, and delete all its children’s contents first (sub-files or sub-directories), and delete the parent later. This example […]
In Java, we can use the NIO Files.createDirectory to create a directory or Files.createDirectories to create a directory including all nonexistent parent directories. try { Path path = Paths.get("/home/mkyong/a/b/c/"); //java.nio.file.Files; Files.createDirectories(path); System.out.println("Directory is created!"); } catch (IOException e) { System.err.println("Failed to create directory!" + e.getMessage()); } 1. Create Directory – Java NIO 1.1 We can […]
This article shows how to move a file to another directory in the same file drive or remote server. Files.move – Move file in local system. JSch – Move file to remove server (SFTP) 1. Move file to another directory This Java example uses NIO Files.move to move a file from to another directory in […]
In Java, we can use the following two Files.createTempFile() methods to create a temporary file in the default temporary-file directory. Path createTempFile(Path dir, String prefix, String suffix, FileAttribute<?>… attrs) throws IOException Path createTempFile(String prefix, String suffix, FileAttribute<?>… attrs) throws IOException The default temporary file folder is vary on operating system. Windows – %USER%\AppData\Local\Temp Linux – […]
In Java, we can use the NIO Files.setLastModifiedTime(path, FileTime) to update the last modified date or time of a file. Path path = Paths.get("/path/file"); LocalDate newLocalDate = LocalDate.of(1997, 12, 31); // year, month, dayOfMonth, hour, minute, second LocalDateTime newLocalDateTime = LocalDateTime.of(1999, 9, 30, 10, 30, 22); // convert LocalDateTime to Instant Instant instant = newLocalDateTime.toInstant(ZoneOffset.UTC); […]
This article shows how to use the following Java APIs to append text to the end of a file. Files.write – Append a single line to a file, Java 7. Files.write – Append multiple lines to a file, Java 7, Java 8. Files.writeString – Java 11. FileWriter FileOutputStream FileUtils – Apache Commons IO. In Java, […]
Java I/O tutorial with full example, including file , temporary file and directory manipulation, file serialization and compression with Zip or GZip.
In Java (@since 1.7), we can use the NIO Files.readAttributes to get all the file metadata, including the file creation date. Path file = Paths.get(fileName); BasicFileAttributes attr = Files.readAttributes(file, BasicFileAttributes.class); System.out.println("creationTime: " + attr.creationTime()); // creationTime: 2020-07-20T09:29:54.627222Z 1. Files.readAttributes (NIO) This example uses Files.readAttributes to print the file creation date. GetCreationDate1.java package com.mkyong.io.howto; import java.io.IOException; […]
This article shows four ways to copy a file in Java. Files.copy (NIO) Apache Commons IO Guava Plain Java In Java 7+, the NIO Files.copy is the simplest way to copy a file, because it is a built-in API. Before Java 7, the Apache Commons IO FileUtils.copyFile is a preferable solution because the legacy IO […]
In Java, we can use the NIO Files.delete() or Files.deleteIfExists() to delete a temporary file, it works the same like delete a regular text file. // create a temporary file Path path = Files.createTempFile(null, ".log"); // delete Files.delete(path); // or if(Files.deleteIfExists(path)){ // success }else{ // file does not exist } 1. Delete Temporary File – […]
In Java, we can use the NIO Files.delete(Path) and Files.deleteIfExists(Path) to delete a file. 1. Delete a file with Java NIO 1.1 The Files.delete(Path) deletes a file, returns nothing, or throws an exception if it fails. DeleteFile1.java package com.mkyong.io.file; import java.io.IOException; import java.nio.file.Files; import java.nio.file.Paths; public class DeleteFile1 { public static void main(String[] args) { […]
In Java, we can use the NIO Files.move(source, target) to rename or move a file. import java.io.IOException; import java.nio.file.Files; import java.nio.file.Path; import java.nio.file.Paths; //… Path source = Paths.get("/home/mkyong/newfolder/test1.txt"); Path target = Paths.get("/home/mkyong/newfolder/test2.txt"); try{ Files.move(source, target); } catch (IOException e) { e.printStackTrace(); } 1. Rename a file in the same directory. 1.1 This example renames a […]
In Java, we can use BufferedWriter to write content into a file. // jdk 7 try (FileWriter writer = new FileWriter("app.log"); BufferedWriter bw = new BufferedWriter(writer)) { bw.write(content); } catch (IOException e) { System.err.format("IOException: %s%n", e); } Note If possible, uses Files.write instead, one line, simple and nice. List<String> list = Arrays.asList("Line 1", "Line 2"); […]
The temporary file is just a regular file created on a predefined directory. In Java, we can use the NIO Files.write() to write data to a temporary file. // create a temporary file Path tempFile = Files.createTempFile(null, null); // Writes a string to the above temporary file Files.write(tempFile, "Hello World\n".getBytes(StandardCharsets.UTF_8)); // Append List<String> content = […]
