JAVA EE: XML Marshalling and UnMarshalling using Spring and JAXB XML binding framework

Monday, 28 January 2019

XML Marshalling and UnMarshalling using Spring and JAXB XML binding framework - Annotation Config

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Introduction: What is XML Marshalling and Unmarshalling?

In modern software development, converting Java objects to XML and vice versa is a common requirement for data exchange. This process is known as Object-XML Mapping (OXM):

Marshalling: Converting a Java object into an XML document format.
Unmarshalling: Reading an XML document and deserializing it back into a Java object.

Why Use Spring OXM with JAXB?

Spring provides an abstraction layer through the Spring OXM module, which simplifies working with different XML binding frameworks like JAXB (Java Architecture for XML Binding). Using annotation-based configuration makes your code cleaner, easier to maintain, and eliminates the need for bulky XML mapping files.

Key Steps Covered in This Tutorial

Model Setup: Annotating the Java domain class using standard JAXB annotations (@XmlRootElement, @XmlElement, etc.).
Spring Configuration: Configuring Jaxb2Marshaller using Java-based @Configuration without external XML configs.
Executing Marshalling: Converting the Java entity instance into an XML file stream.
Executing Unmarshalling: Reading back the XML file and validating the restored Java object properties.

Recommended Related Tutorials

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XML Marshalling and UnMarshalling using Spring and JAXB XML binding framework - Annotation Config

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.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>5.1.1.RELEASE</spring.version>

    </properties>

    <dependencies>

        <dependency>

            <groupId>junit</groupId>

            <artifactId>junit</artifactId>

            <version>4.8.2</version>

            <scope>test</scope>

        </dependency>

        <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>

        <dependency>

            <groupId>org.springframework</groupId>

            <artifactId>spring-oxm</artifactId>

            <version>${spring.version}</version>

        </dependency>

    </dependencies>

</project>

Company.java

package com.ram.core.model;

import javax.xml.bind.annotation.XmlAccessType;

import javax.xml.bind.annotation.XmlAccessorType;

import javax.xml.bind.annotation.XmlAttribute;

import javax.xml.bind.annotation.XmlElement;

import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement(name = "CompanyInfo", namespace = "com.ram.core")

@XmlAccessorType(XmlAccessType.NONE)

public class Company

{

    @XmlAttribute(name = "Id")

    private Integer id;

    @XmlElement(name = "CompanyName")

    private String companyName;

    @XmlElement(name = "CEO_Name")

    private String ceoName;

    @XmlElement(name = "Number_Of_Employees")

    private Integer numberOfEmployees;

    public Integer getId()

    {

        return id;

    }

    public void setId(Integer id)

    {

        this.id = id;

    }

    public String getCompanyName()

    {

        return companyName;

    }

    public void setCompanyName(String companyName)

    {

        this.companyName = companyName;

    }

    public String getCeoName()

    {

        return ceoName;

    }

    public void setCeoName(String ceoName)

    {

        this.ceoName = ceoName;

    }

    public Integer getNumberOfEmployees()

    {

        return numberOfEmployees;

    }

    public void setNumberOfEmployees(Integer numberOfEmployees)

    {

        this.numberOfEmployees = numberOfEmployees;

    }

    @Override

    public String toString()

    {

        return "Company [id=" + id + ", companyName=" + companyName

                + ", ceoName=" + ceoName + ", numberOfEmployees="

                + numberOfEmployees + "]";

    }

}

XMLConverter.java

package com.ram.core;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.IOException;

import javax.xml.transform.stream.StreamResult;

import javax.xml.transform.stream.StreamSource;

import org.springframework.oxm.Marshaller;

import org.springframework.oxm.Unmarshaller;

public class XMLConverter

{

    private Marshaller marshaller;  

    private Unmarshaller unmarshaller;

    public Marshaller getMarshaller()

    {

        return marshaller;

    }

    public void setMarshaller(Marshaller marshaller)

    {

        this.marshaller = marshaller;

    }

    public Unmarshaller getUnmarshaller()

    {

        return unmarshaller;

    }

    public void setUnmarshaller(Unmarshaller unmarshaller)

    {

        this.unmarshaller = unmarshaller;

    }

    public void convertFromObjectToXML(Object object, String filepath)

            throws IOException

    {

        FileOutputStream os = null;

        try

        {

            os = new FileOutputStream(filepath);

            getMarshaller().marshal(object, new StreamResult(os));

        }

        finally

        {

            if (os != null)

            {

                os.close();

            }

        }

    }

    public Object convertFromXMLToObject(String xmlfile)

            throws IOException

    {

        FileInputStream is = null;

        try

        {

            is = new FileInputStream(xmlfile);

            return getUnmarshaller().unmarshal(new StreamSource(is));

        }

        finally

        {

            if (is != null)

            {

                is.close();

            }

        }

    }

}

AppConfig.java

package com.ram.core.config;

import java.util.HashMap;

import java.util.Map;

import org.springframework.context.annotation.Bean;

import org.springframework.context.annotation.Configuration;

import org.springframework.oxm.jaxb.Jaxb2Marshaller;

import com.ram.core.XMLConverter;

@Configuration

public class AppConfig

{

    @Bean

    public XMLConverter getHandler()

    {

        XMLConverter xmlConverter = new XMLConverter();

        xmlConverter.setMarshaller(getJaxbMarshaller());

        xmlConverter.setUnmarshaller(getJaxbMarshaller());

        return xmlConverter;

    }

    @Bean

    public Jaxb2Marshaller getJaxbMarshaller()

    {

        Jaxb2Marshaller jaxb2Marshaller = new Jaxb2Marshaller();

        jaxb2Marshaller.setPackagesToScan("com.ram.core.model");

        Map<String, Object> map = new HashMap<String, Object>();

        map.put("jaxb.formatted.output", true);

        jaxb2Marshaller.setMarshallerProperties(map);

        return jaxb2Marshaller;

    }

}

App.java

package com.ram.core;

import java.io.IOException;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;

import com.ram.core.config.AppConfig;

import com.ram.core.model.Company;

public class App

{

    private static final String XML_FILE_NAME = "company.xml";

    public static void main(String[] args) throws IOException

    {

        AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(

                AppConfig.class);

        XMLConverter converter = (XMLConverter) context

                .getBean(XMLConverter.class);

        Company company = new Company();

        company.setId(201);

        company.setCompanyName("Google");

        company.setCeoName("Peter");

        company.setNumberOfEmployees(50000);

        // from object to XML file

        converter.convertFromObjectToXML(company, XML_FILE_NAME);

        System.out.println("Converted Object to XML!");

        // from XML to object

        Company company2 = (Company) converter

                .convertFromXMLToObject(XML_FILE_NAME);

        System.out.println(company2);

        System.out.println("Converted XML to Object!");

    }

}

Output:

Converted Object to XML!

Company [id=201, companyName=Google, ceoName=Peter, numberOfEmployees=50000]

Converted XML to Object!

company.xml

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>

<ns2:CompanyInfo xmlns:ns2="com.ram.core" Id="201">

    <CompanyName>Google</CompanyName>

    <CEO_Name>Peter</CEO_Name>

    <Number_Of_Employees>50000</Number_Of_Employees>

</ns2:CompanyInfo>