mkyong In Java, we can use Files.readAllBytes(path) to convert a File object into a byte[]. import java.nio.file.Files; import java.nio.file.Path; import java.nio.file.Paths; String filePath = "/path/to/file"; // file to byte[], Path byte[] bytes = Files.readAllBytes(Paths.get(filePath)); // file to byte[], File -> Path File file = new File(filePath); byte[] bytes = Files.readAllBytes(file.toPath()); P.S The NIO Files class is …
Updated on 25 July 2012 – Upgrade article to use Spring 3 and Quartz 1.8.6 (it was Spring 2.5.6 and Quartz 1.6) In this tutorial, we will show you how to integrate Spring with Quartz scheduler framework. Spring comes with many handy classes to support Quartz, and decouple your class to Quartz APIs. Tools Used …
Transaction management is required to ensure the data integrity and consistency in database. Spring’s AOP technique is allow developers to manage the transaction declarative. Here’s an example to show how to manage the Hibernate transaction with Spring AOP. P.S Many Hibernate and Spring configuration files are hidden, only some important files are shown, if you …
Quartz is a powerful and advance scheduler framework, to help Java developer to scheduler a job to run at a specified date and time. This tutorial show you how to develop a scheduler job using Quartz 1.6.3. Note This example is a bit outdate, unless you are still using the old Quartz 1.6.3 library, otherwise, …
This tutorial shows how to use the JDOM to modify an XML file. Table of contents 1. Download the JDOM 2.x 2. The XML file, before and after 3. Modify XML file 4. Find and remove XML elements 5. Download Source Code 6. References P.S Tested with JDOM 2.0.6 Note We need to understand how …
Java XML Tutorials with full example, including how to read, write and modify the xml file with DOM, SAX and JDOM parsers. And also how to convert object to / from XML via JAXB.
Note Learn the JDK Timer scheduler example without Spring and compare the different with this example. In this example, you will use Spring’s Scheduler API to schedule a task. 1. Scheduler Task Create a scheduler task… package com.mkyong.common; public class RunMeTask { public void printMe() { System.out.println("Run Me ~"); } } <bean id="runMeTask" class="com.mkyong.common.RunMeTask" /> …
This tutorial shows how to use the Java built-in DOM APIs to write data to an XML file. Table of contents 1. Write XML to a file 2. Pretty Print XML 3. Write XML elements, attributes, comments CDATA, etc 4. DOM FAQs 4.1 How to disable the XML declaration? 4.2 How to change the XML …
TestNG tutorial with full example, introduce the TestNG basic usage, annotation support, and test case for expected exception test, ignore test, time test, suite test, parameterized test, dependency test and etc
JUnit tutorial with full example, introduce the JUnit basic usage, annotation support, and test case for expected exception test, ignore test, time test, suite test, parameterized test and etc
Spring tutorial with full example, including Spring’s basic usage, bean configuration, dependency injection, AOP, integration with JDBC, Hibernate , Struts, Quartz, E-mail and etc
JDK Timer is a simple scheduler for a specified task for repeated fixed-delay execution. To use this, you have to extends the TimerTask abstract class, override the run() method with your scheduler function. RunMeTask.java package com.mkyong.common; import java.util.TimerTask; public class RunMeTask extends TimerTask { @Override public void run() { System.out.println("Run Me ~"); } } Now, …
Download It – Spring-Hibernate-Annotation-Example.zip In last tutorial, you use Maven to create a simple Java project structure, and demonstrate how to use Hibernate in Spring framework to do the data manipulation works(insert, select, update and delete) in MySQL database. In this tutorial, you will learn how to do the same thing in Spring and Hibernate …
Apache Maven Tutorial – A series of simple and quick Maven examples.
Hibernate tutorial with full example, including Hibernate configuration, association relationship, HQL, criteria, transaction, tips, performance, integration with Spring, Struts and etc
Spring’s resource loader provides a very generic getResource() method to get the resources like (text file, media file, image file…) from file system , classpath or URL. You can get the getResource() method from the application context. Here’s an example to show how to use getResource() to load a text file from 1. File system …
Here’s an example to use Spring to send e-mail that has attachments via Gmail SMTP server. In order to contains the attachment in your e-mail, you have to use Spring’s JavaMailSender & MimeMessage , instead of MailSender & SimpleMailMessage. 1. Project dependency Add the JavaMail and Spring’s dependency. File : pom.xml <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 …
In last Spring’s email tutorial, you hard-code all the email properties and message content in the method body, it’s not practical and should be avoid. You should consider define the email message template in the Spring’s bean configuration file. 1. Project dependency Add the JavaMail and Spring’s dependency. File : pom.xml <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 …
Often times, most Spring developers just put the entire deployment details (database details, log file path) in XML bean configuration file as following : <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd"> <bean id="customerDAO" class="com.mkyong.customer.dao.impl.JdbcCustomerDAO"> <property name="dataSource" ref="dataSource" /> </bean> <bean id="customerSimpleDAO" class="com.mkyong.customer.dao.impl.SimpleJdbcCustomerDAO"> <property name="dataSource" ref="dataSource" /> </bean> <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource"> <property name="driverClassName" value="com.mysql.jdbc.Driver" /> <property name="url" value="jdbc:mysql://localhost:3306/mkyongjava" …
Spring comes with a useful ‘org.springframework.mail.javamail.JavaMailSenderImpl‘ class to simplify the e-mail sending process via JavaMail API. Here’s a Maven build project to use Spring’s ‘JavaMailSenderImpl‘ to send an email via Gmail SMTP server. 1. Project dependency Add the JavaMail and Spring’s dependency. File : pom.xml <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.mkyong.common</groupId> <artifactId>SpringExample</artifactId> <packaging>jar</packaging> <version>1.0-SNAPSHOT</version> …
In Spring, you can either implements InitializingBean and DisposableBean interface or specify the init-method and destroy-method in bean configuration file for the initialization and destruction callback function. In this article, we show you how to use annotation @PostConstruct and @PreDestroy to do the same thing. Note The @PostConstruct and @PreDestroy annotation are not belong to …
In this article, we will show you how to send an email via Gmail SMTP server. To send email in Java, we need JavaMail pom.xml <dependency> <groupId>com.sun.mail</groupId> <artifactId>javax.mail</artifactId> <version>1.6.2</version> </dependency> 1. Gmail SMTP via TLS SMTP = smtp.gmail.com Port = 587 SendEmailTLS.java package com.mkyong; import javax.mail.*; import javax.mail.internet.InternetAddress; import javax.mail.internet.MimeMessage; import java.util.Properties; public class SendEmailTLS …
In last Spring AOP examples – advice, pointcut and advisor, you have to manually create a proxy bean (ProxyFactoryBean) for each beans whose need AOP support. This is not an efficient way, for example, if you want all of your DAO classes in customer module to implement the AOP feature with SQL logging support (advise), …
In Spring, you can use init-method and destroy-method as attribute in bean configuration file for bean to perform certain actions upon initialization and destruction. Alternative to InitializingBean and DisposableBean interface. Example Here’s an example to show you how to use init-method and destroy-method. package com.mkyong.customer.services; public class CustomerService { String message; public String getMessage() { …
In Spring, InitializingBean and DisposableBean are two marker interfaces, a useful way for Spring to perform certain actions upon bean initialization and destruction. For bean implemented InitializingBean, it will run afterPropertiesSet() after all bean properties have been set. For bean implemented DisposableBean, it will run destroy() after Spring container is released the bean. Example Here’s …
JavaMail is now available in Maven Central repository. pom.xml <dependency> <groupId>com.sun.mail</groupId> <artifactId>javax.mail</artifactId> <version>1.6.2</version> </dependency> If you want to use the core JavaMail API to send email, you have to get the JavaMail library – mail.jar and activation.jar. Unfortunately, those libraries are not available in the Maven central repository, you have to download it from java.Net …
In Spring, bean scope is used to decide which type of bean instance should be return from Spring container back to the caller. 5 types of bean scopes supported : singleton – Return a single bean instance per Spring IoC container prototype – Return a new bean instance each time when requested request – Return …
In last Spring AOP advice examples, the entire methods of a class are intercepted automatically. But for most cases, you may just need a way to intercept only one or two methods, this is what ‘Pointcut’ come for. It allow you to intercept a method by it’s method name. In addition, a ‘Pointcut’ must be …
Spring AOP + AspectJ Using AspectJ is more flexible and powerful, please refer to this tutorial – Using AspectJ annotation in Spring AOP. Spring AOP (Aspect-oriented programming) framework is used to modularize cross-cutting concerns in aspects. Put it simple, it’s just an interceptor to intercept some processes, for example, when a method is execute, Spring …
In this Spring auto component scanning tutorial, you learn about how to make Spring auto scan your components. In this article, we show you how to do component filter in auto scanning process. 1. Filter component – include See following example to use Spring “filtering” to scan and register components’ name which matched defined “regex”, …
Normally you declare all the beans or components in XML bean configuration file, so that Spring container can detect and register your beans or components. Actually, Spring is able to auto scan, detect and instantiate your beans from pre-defined project package, no more tedious beans declaration in in XML file. Following is a simple Spring …
This example will use Maven to create a simple Java project structure, and demonstrate how to use Hibernate in Spring framework to do the data manipulation works(insert, select, update and delete) in MySQL database. Final project structure Your final project file structure should look exactly like following, if you get lost in the folder structure …
In JdbcTemplate, SQL parameters are represented by a special placeholder “?” symbol and bind it by position. The problem is whenever the order of parameter is changed, you have to change the parameters bindings as well, it’s error prone and cumbersome to maintain it. To fix it, you can use “Named Parameter“, whereas SQL parameters …
Here are few examples to show how to use SimpleJdbcTemplate query() methods to query or extract data from database. In JdbcTemplate query(), you need to manually cast the returned result to desire object type, and pass an Object array as parameters. In SimpleJdbcTemplate, it is more user friendly and simple. jdbctemplate vesus simplejdbctemplate Please compare …
In this tutorial, we show you how to use batchUpdate() in SimpleJdbcTemplate class. See batchUpdate() example in SimpleJdbcTemplate class. //insert batch example public void insertBatch(final List<Customer> customers){ String sql = "INSERT INTO CUSTOMER " + "(CUST_ID, NAME, AGE) VALUES (?, ?, ?)"; List<Object[]> parameters = new ArrayList<Object[]>(); for (Customer cust : customers) { parameters.add(new Object[] …
Here are a few examples to show you how to use Spring JdbcTemplate to query or extract data from database. Technologies used : Spring Boot 2.1.2.RELEASE Spring JDBC 5.1.4.RELEASE Maven 3 Java 8 In Short: jdbcTemplate.queryForObject for single row or value jdbcTemplate.query for multiple rows or list Note The article is updated from Spring core …
In Spring AOP, you have to include the cglib library into your build path to avoid the “Cannot proxy target class because CGLIB2 is not available” error message. Exception in thread "main" org.springframework.beans.factory.BeanCreationException: Error creating bean with name ‘customerServiceProxy’: FactoryBean threw exception on object creation; nested exception is org.springframework.aop.framework.AopConfigException: Cannot proxy target class because CGLIB2 …
Spring JdbcTemplate batch insert, batch update and also @Transactional examples. Technologies used : Spring Boot 2.1.2.RELEASE Spring JDBC 5.1.4.RELEASE Maven 3 Java 8 1. Batch Insert 1.1 Insert a batch of SQL Inserts together. BookRepository.java import org.springframework.jdbc.core.JdbcTemplate; import org.springframework.jdbc.core.BatchPreparedStatementSetter; public int[] batchInsert(List<Book> books) { return this.jdbcTemplate.batchUpdate( "insert into books (name, price) values(?,?)", new BatchPreparedStatementSetter() { …
Spring example to show you how to inject a “Date” into bean property. package com.mkyong.common; import java.util.Date; public class Customer { Date date; public Date getDate() { return date; } public void setDate(Date date) { this.date = date; } @Override public String toString() { return "Customer [date=" + date + "]"; } } Bean configuration …
In last tutorial, you are able to get the MessageSource via ApplicationContext. But for a bean to get the MessageSource, you have to implement the MessageSourceAware interface. Example A CustomerService class, implement the MessageSourceAware interface, has a setter method to set the MessageSource property. During Spring container initialization, if any class which implements the MessageSourceAware …