Huong Dan Java - Page 65 of 84 - Java development tutorials

Read properties files in Spring using context namespace

In this tutorial, I will show you how to read file properties in Spring using the context namespace. But first, let’s create an example project. I will use Java 17 for this example:

<properties>
  <maven.compiler.source>17</maven.compiler.source>
  <maven.compiler.target>17</maven.compiler.target>
</properties>

<maven.compiler.source>17</maven.compiler.source>

<maven.compiler.target>17</maven.compiler.target>

</properties>

Spring framework dependency:

<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-context</artifactId>
  <version>6.0.3</version>
</dependency>

<groupId>org.springframework</groupId>

<artifactId>spring-context</artifactId>

</dependency>

Class Application:

package com.huongdanjava.spring;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Application {

  public static void main(String[] args) {
    ApplicationContext context = new ClassPathXmlApplicationContext("spring.xml");
  }
}

package com.huongdanjava.spring;

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Application {

public static void main(String[] args) {

ApplicationContext context = new ClassPathXmlApplicationContext("spring.xml");

}

In our example, the… Read More

Define HTTP request method for Controller in Spring MVC

9 years ago by Khanh NguyenSpring MVC

The @RequestMapping annotation beside allows us to define the request URL, it also allows us to define the HTTP request method for the controller in Spring MVC using its method attribute. In this tutorial, we will learn more about this method property. In the project that… Read More

Overview about Controller in Spring MVC

9 years ago by Khanh NguyenSpring MVC

In the MVC model, the controller receives the request from the user, processes the request, builds the data for the view (model), and selects the view to return the result to the user. In this tutorial, we will look at an overview about the controller… Read More

Deploy Spring Boot application to Cloud Foundry using Spring Boot Dashboard in Spring Tool Suite

9 years ago by Khanh NguyenSpring Boot

The Spring Boot Dashboard is a function of the Spring Tool Suite which allows us to manage all applications that use Spring Boot in our workspace. Using the Spring Boot Dashboard, in addition to starting and stopping one or more Spring Boot applications, it also… Read More

Login into Pivotal Cloud Foundry

9 years ago by Khanh NguyenCloud Foundry

Using the Cloud Foundry CLI can help us talk directly to Cloud Foundry Providers like Pivotal Cloud Foundry. In this tutorial, I will show you how to use the Cloud Foundry CLI to login into Pivotal Cloud Foundry and view the information which we want.… Read More

Convert JSON to Java object using Jackson

9 years ago by Khanh NguyenJackson

In my previous tutorial, I showed you how to convert Java object to JSON using the Jackson library. So what if we wanted to do the reverse, ie converting JSON to Java object? In this tutorial, we will learn more about that. As an example,… Read More

Convert Java object to JSON using Jackson

9 years ago by Khanh NguyenJackson

Jackson is a standard library for handling JSON-related issues in Java. In this tutorial, we will learn how to convert Java objects to JSON using the Jackson library. First, I will illustrate with a Maven project as follows: Jackson dependency is as follows:

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.18.1</version>
</dependency>

<groupId>com.fasterxml.jackson.core</groupId>

<artifactId>jackson-databind</artifactId>

</dependency>

The… Read More

flatMap() method of Optional object in Java

9 years ago by Khanh NguyenJava Basic

As you all know, the Optional object is a generic object, its data type can be any object, and therefore, we can meet the case that its data type is also an Optional object, such as: Optional<Optional<String>>. To resolve this problem, Java introduces us to… Read More

isPresent() method of Optional object in Java

9 years ago by Khanh NguyenJava Basic

This method will check whether an Optional object is not empty? If this object is empty, it returns false. For example:

package com.huongdanjava.javaexample;

import java.util.Optional;

public class Example {

	public static void main(String[] args) {
		String s = new String("Khanh");

		Optional<String> opt = Optional.ofNullable(s);
		System.out.println(opt.isPresent());
	}

}

package com.huongdanjava.javaexample;

import java.util.Optional;

public class Example {

public static void main(String[] args) {

String s = new String("Khanh");

Optional<String> opt = Optional.ofNullable(s);

System.out.println(opt.isPresent());

}

Result:

map() method of Optional object in Java

9 years ago by Khanh NguyenJava Basic

This method first will check whether our Optional object is empty or not? If not empty, convert its value to another value. Similar to the filter() method, this method returns an Optional object with a value after conversion. For example:

package com.huongdanjava.javaexample;

import java.util.Optional;

public class Example {

	public static void main(String[] args) {
		String s = new String("Khanh");

		Optional<String> opt = Optional.ofNullable(s);
		opt.map(x -> x.toLowerCase())
			.filter(x -> x.contains("k"))
			.ifPresent(x -> System.out.println("Name: " + x));
	}

}

package com.huongdanjava.javaexample;

import java.util.Optional;

public class Example {

public static void main(String[] args) {

String s = new String("Khanh");

Optional<String> opt = Optional.ofNullable(s);

opt.map(x -> x.toLowerCase())

.filter(x -> x.contains("k"))

.ifPresent(x -> System.out.println("Name: " + x));

}

In the above example,… Read More