Create a simple Spring application

Environmental installation has been completed, the next to create a simple Spring application.

Create a Spring application steps:

Create a maven project
Add spring library dependencies
Creating Bean class
Add xml file Bean's assembly
Create Main Class
Run the application

1. Create a maven project

Open the Eclipse, if it is not set up a development environment, reference may Spring development environment to build (the Eclipse) , menu selection: File > New > Maven Projectpop-up dialog, the following operation of FIG.

Click the Nextpop-up dialog, as shown operation

Click Finishto complete the project creation, the project is structured as follows:

Project directory Description:

src - the source directory
- main - Code
  - java - Java code directory
  - resources - resources directory profiles, etc.
- test - test code
target - the compiled output directory

pom.xml file in the root directory of the project is dependent maven package configuration file.

2. Add the spring library dependencies

Make use of the spring module added to the project. Modifications pom.xml, introduction of the following modules:

spring-core
spring-beans
spring-context

The complete pom.xmlcontents of the file:

<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/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.qikegu.demo</groupId>
    <artifactId>spring-helloworld</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <dependencies>
        <!-- https://mvnrepository.com/artifact/org.springframework/spring-core -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>5.1.5.RELEASE</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework/spring-beans -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
            <version>5.1.5.RELEASE</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework/spring-context -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.1.5.RELEASE</version>
        </dependency>

    </dependencies>

</project>

Next, add the code, it will add the following files:

Customer.java - bean class
applicationContext.xml - bean configuration files
Hello.java - master class

The final project structure shown below:

It will be described later in detail.

3. Create Bean class

Add CustomerBean class. Project root directory right pop-up menu, select: New -> Filespecify the directory .../src/main/java/com/qikegu/demo, add Customer.java file.

Customer.javaCode:

package com.qikegu.demo;

public class Customer { 

    String name; 
    
    public String getName() { 
        return name; 
    }
    
    public void setName(String name) { 
        this.name = name; 
    }
    
    public void displayInfo() { 
        System.out.println("Hello: "+ name); 
    } 
}

This is a simple bean class, and contains a property getter and setter methods, another displayInfo()method will print the name of the customer.

4. Add the Bean xml file assembly

In the resources directory, add file xml assembly of Bean:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">

    <bean id="customerBean" class="com.qikegu.demo.Customer"> 
        <property name="name" value="奇客谷"></property> 
    </bean>
</beans>

<bean>Marked as specified class definition bean.
<property>Tag is a child element of the bean, for setting the Customerattribute class, the property value is assigned by the IoC container to the Customerclass instance.

5. Create Main Class

Add a master class file Hello.java, as follows:

package com.qikegu.demo;

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

public class Hello { 
    public static void main(String[] args) { 
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
        Customer customerBean = (Customer) context.getBean("customerBean"); 
        customerBean.displayInfo(); 
        
        ((ClassPathXmlApplicationContext) context).close();
    } 
}

6. Run the application

Right-click the Hello.javapop-up menu, select Run As > Java Applicationthe output:

Hello: 奇客谷