How to do Dependency Injection using Spring Expression Language SpEL(Annotation) | Spring Tutorial

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How to do Dependency Injection using Spring Expression Language SpEL(Annotation) | Spring Tutorial

How to do Dependency Injection using Spring Expression Language SpEL(Annotation) | Spring Tutorial

How to do Dependency Injection using Spring Expression Language SpEL(Annotation) | Spring Tutorial

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%20http://maven.apache.org/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.ram.core</groupId>
    <artifactId>SpringDemo</artifactId>
    <packaging>jar</packaging>
    <version>1.0-SNAPSHOT</version>
    <name>SpringDemo</name>
    <url>http://maven.apache.org</url>

    <properties>
        <spring.version>5.0.5.RELEASE</spring.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>3.8.1</version>
            <scope>test</scope>
        </dependency>

        <!-- Spring 5 dependencies -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${spring.version}</version>
        </dependency>
    </dependencies>
</project>

Address.java

package com.ram.model;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

@Component("address")
public class Address
{
    @Value("Chennai") //inject String directly
    private String city;
   
    @Value("TamilNadu")
    private String state;

    public String getCity()
    {
        return city;
    }

    public void setCity(String city)
    {
        this.city = city;
    }

    public String getState()
    {
        return state;
    }

    public void setState(String state)
    {
        this.state = state;
    }

    @Override
    public String toString()
    {
        return "Address [city=" + city + ", state=" + state + "]";
    }

}

Employee.java

package com.ram.model;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

@Component("employee")
public class Employee
{
    @Value("100") //inject int directly
    private int id;
   
    @Value("Peter")
    private String name;
   
    @Value("#{address.state}")
    private String employeeState;
   
    @Value("#{address}")
    private Address address;

    public int getId()
    {
        return id;
    }

    public void setId(int id)
    {
        this.id = id;
    }

    public String getName()
    {
        return name;
    }

    public void setName(String name)
    {
        this.name = name;
    }

    public String getEmployeeState()
    {
        return employeeState;
    }

    public void setEmployeeState(String employeeState)
    {
        this.employeeState = employeeState;
    }

    public Address getAddress()
    {
        return address;
    }

    public void setAddress(Address address)
    {
        this.address = address;
    }

    @Override
    public String toString()
    {
        return "Employee [id=" + id + ", name=" + name + ", employeeState="
                + employeeState + ", address=" + address + "]";
    }

}

applicationContext.xml

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-4.3.xsd
    http://www.springframework.org/schema/context
    http://www.springframework.org/schema/context/spring-context-4.3.xsd">

    <context:component-scan base-package="com.ram" />

</beans>

App.java

package com.ram.core;

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

import com.ram.model.Employee;

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

        System.out.println("---------------------------------------");

        Employee employee = (Employee) context.getBean("employee");
        System.out.println(
                "Got employee object from the ApplicationContext(Spring Container)");
        System.out.println(employee);  
    }

}

Output

Aug 31, 2018 10:42:19 AM org.springframework.context.support.AbstractApplicationContext prepareRefresh
INFO: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@736e9adb: startup date [Fri Aug 31 10:42:19 IST 2018]; root of context hierarchy
Aug 31, 2018 10:42:19 AM org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
INFO: Loading XML bean definitions from class path resource [applicationContext.xml]
---------------------------------------
Got employee object from the ApplicationContext(Spring Container)
Employee [id=100, name=Peter, employeeState=TamilNadu, address=Address [city=Chennai, state=TamilNadu]]

Click the below link to download the code:
https://sites.google.com/site/ramj2eev2/java_basics/SpringDemo_Spring_EL_Annotation.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/javaee/tree/master/Spring_2018/SpringDemo_Spring_EL_Annotation

Bitbucket Link:
https://bitbucket.org/ramram43210/spring/src/02e04aa1b68a77d4f5a01ebf111e80370bd99ca8/Spring_2018/SpringDemo_Spring_EL_Annotation/?at=master

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