Working with XML Serialization and Response in Java and Kotlin

_READMEmd

# Working with XML Serialization and Response in Java and Kotlin

## PreRequisite
- Java 17+
- [Optional] Kotlin 1.6+, Few examples will be in Kotlin
- [Optional] IntelliJ CE, You can use your preferred IDE

## Blogs Post
[Deepak Vishwakarma's Medium](https://medium.com/@deepak-v)

Java01.java

// imports
@SpringBootApplication
@RestController
public class XmlDemoApplication {
    public static void main(String args[]) {
        SpringApplication.run(XmlDemoApplication.class, args);
    }
@RequestMapping(
            value = "/xml",
            method = RequestMethod.GET,
            produces = {"application/xml"}
    )
    public String xml(
            @RequestParam(value = "name", defaultValue = "John Doe")
            String name
    ) {
        return String.format("<name>%s</name>", name);
    }
}

Java02.java

// Imports
@SpringBootApplication
@RestController
public class XmlDemoApplication {

    public static void main(String args[]) {
        SpringApplication.run(XmlDemoApplication.class, args);
    }


    @RequestMapping(value = "/xml", method = RequestMethod.POST, produces = {"application/xml"})
    public String xml(@RequestBody() Person person) {
        return """
                <?xml version="1.0" encoding="UTF-8" ?>
                <Person>
                  <age>%s</age>
                  <name>%s</name>
                  <company>%s</company>
                  <email>%s</email>
                  <address>
                    <street>%s</street>
                    <city>%s</city>
                    <state>%s</state>
                    <zip>%s</zip>
                  </address>
                </Person>
                """.formatted(
                person.age, person.name, person.company, person.email,
                person.address.street, person.address.city,
                person.address.state, person.address.zip
        );
    }
}



class Person {
    public int age;
    public String name;
    public String company;
    public String email;
    public Address address;
}

class Address {
    public String street;
    public String city;
    public String state;
    public int zip;
}

Java03.java

// XmlDemoApplication.java
@SpringBootApplication
@RestController
public class XmlDemoApplication {
    static Mustache mustache = new DefaultMustacheFactory().compile("person-response.mustache");
@RequestMapping(
            value = "/template",
            method = RequestMethod.POST,
            produces = {"application/xml"}
    )
    public String template(@RequestBody() Person person) throws IOException {
        StringWriter writer = new StringWriter();
        mustache.execute(writer, person).flush();
        return writer.toString();
    }
}

Java04.java

@SpringBootApplication
@RestController
public class XmlDemoApplication {

@RequestMapping(
            value = "/serialize",
            method = RequestMethod.POST,
            produces = {"application/xml"}
    )
    public Person serialize(@RequestBody() Person person) throws IOException {
        person.name = "[Updated] %s".formatted(person.name);
        return person;
    }
    
}
@JacksonXmlRootElement
@JsonRootName("person")
class Person {
    public int age;
    public String name;
    public String company;
    public String email;
    public Address address;
}

Kotlin01.kt

@SpringBootApplication
@RestController
@RequestMapping(path = ["/kt/"])
class XmlDemoKt {
    @RequestMapping(value = ["/xml"], method = [RequestMethod.GET], produces = ["application/xml"])
    fun xml(
        @RequestParam(value = "name", defaultValue = "John Doe") name: String?
    ) = String.format("<name>%s</name>", name)
}
fun main(args: Array<String>) {
    runApplication<XmlDemoKt>(*args)
}

Kotlin02.kt

@SpringBootApplication
@RestController
@RequestMapping(path = ["/kt/"])
class XmlDemoKt {

    @RequestMapping(value = ["/xml"], method = [RequestMethod.POST], produces = ["application/xml"])
    fun xml(
        @RequestBody p: PersonKt
    ): String {
        return """
    <?xml version="1.0" encoding="UTF-8" ?>
    <Person>
      <age>${p.age}</age>
      <name>${p.name}</name>
      <company>${p.company}</company>
      <email>${p.email}</email>
      <address>
            <street>${p.address.street}</street>
            <city>${p.address.city}</city>
            <state>${p.address.state}</state>
            <zip>${p.address.zip}</zip>
      </address>
    </Person>
    """.trimIndent()
    }


}

fun main(args: Array<String>) {
    runApplication<XmlDemoKt>(*args)
}


data class PersonKt(
    val age: Long,
    val name: String,
    val company: String,
    val email: String,
    val address: AddressKt
)

data class AddressKt(
    val street: String,
    val city: String,
    val state: String,
    val zip: Long
)

Kotlin03.kt

// XmlDemoKt.kt
@SpringBootApplication
@RestController
@RequestMapping(path = ["/kt/"])
class XmlDemoKt {
    
    @RequestMapping(
        value = ["/template"],
        method = [RequestMethod.POST],
        produces = ["application/xml"]
    )
    fun template(@RequestBody p: PersonKt): String {
        val writer = StringWriter()
        mustache.execute(writer, p).flush()
        return writer.toString()
    }
companion object {
        val mustache = DefaultMustacheFactory()
            .compile("person-response.mustache")
    }
}

Kotlin04.kt

@SpringBootApplication
@RestController
@RequestMapping(path = ["/kt/"])
class XmlDemoKt {
    @Bean
    @Primary
    fun objectMapper() = ObjectMapper() .registerModule(kotlinModule())
@RequestMapping(
        value = ["/serialize"],
        method = [RequestMethod.POST],
        produces = ["application/xml"]
    )
    fun serialize(@RequestBody p: PersonKt): PersonKt {
        return p.copy(name = "[Updated] ${p.name}")
    }
}
@JacksonXmlRootElement
@JsonRootName("person")
data class PersonKt(
    val age: Long,
    val name: String,
    val company: String,
    val email: String,
    val address: AddressKt
)

person-response.mustache

<?xml version="1.0" encoding="UTF-8" ?>
<Person>
    <age>{{age}}</age>
    <name>{{name}}</name>
    <company>{{company}}</company>
    <email>{{email}}</email>
    <address>
        <street>{{address.street}}</street>
        <city>{{address.city}}</city>
        <state>{{address.state}}</state>
        <zip>{{address.zip}}</zip>
    </address>
</Person>

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.7.0</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>
	<groupId>dev.dechipher.xml</groupId>
	<artifactId>xml-demo</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>xml-demo</name>
	<description>Demo app for xml writing in Kotlin and Java</description>
	<properties>
		<java.version>17</java.version>
		<kotlin.version>1.6.21</kotlin.version>
	</properties>
	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>
		<dependency>
			<groupId>com.fasterxml.jackson.module</groupId>
			<artifactId>jackson-module-kotlin</artifactId>
		</dependency>
		<dependency>
			<groupId>com.fasterxml.jackson.dataformat</groupId>
			<artifactId>jackson-dataformat-xml</artifactId>
		</dependency>
		<dependency>
			<groupId>org.jetbrains.kotlin</groupId>
			<artifactId>kotlin-reflect</artifactId>
		</dependency>
		<dependency>
			<groupId>org.jetbrains.kotlin</groupId>
			<artifactId>kotlin-stdlib-jdk8</artifactId>
		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>

		<dependency>
			<groupId>com.github.spullara.mustache.java</groupId>
			<artifactId>compiler</artifactId>
			<version>0.9.4</version>
		</dependency>
		<dependency>
			<groupId>dev.dechipher.xml</groupId>
			<artifactId>xml-demo</artifactId>
			<version>0.0.1-SNAPSHOT</version>
		</dependency>
	</dependencies>

	<build>
		<sourceDirectory>${project.basedir}/src/main/kotlin</sourceDirectory>
		<testSourceDirectory>${project.basedir}/src/test/kotlin</testSourceDirectory>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
			<plugin>
				<groupId>org.jetbrains.kotlin</groupId>
				<artifactId>kotlin-maven-plugin</artifactId>
				<configuration>
					<args>
						<arg>-Xjsr305=strict</arg>
					</args>
					<compilerPlugins>
						<plugin>spring</plugin>
					</compilerPlugins>
				</configuration>
				<dependencies>
					<dependency>
						<groupId>org.jetbrains.kotlin</groupId>
						<artifactId>kotlin-maven-allopen</artifactId>
						<version>${kotlin.version}</version>
					</dependency>
				</dependencies>
			</plugin>
		</plugins>
	</build>

</project>

XmlDemoApplication.java

package dev.dechipher.xml.xmldemo;

import com.fasterxml.jackson.annotation.JsonRootName;
import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlRootElement;
import com.github.mustachejava.DefaultMustacheFactory;
import com.github.mustachejava.Mustache;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

import java.io.IOException;
import java.io.StringWriter;

// Imports
@SpringBootApplication
@RestController
public class XmlDemoApplication {
    static Mustache mustache = new DefaultMustacheFactory().compile("person-response.mustache");

    public static void main(String args[]) {
        SpringApplication.run(XmlDemoApplication.class, args);
    }

    @RequestMapping(
            value = "/serialize",
            method = RequestMethod.POST,
            produces = {"application/xml"}
    )
    public Person serialize(@RequestBody() Person person) throws IOException {
        person.name = "[Updated] %s".formatted(person.name);
        return person;
    }

    @RequestMapping(
            value = "/template",
            method = RequestMethod.POST,
            produces = {"application/xml"}
    )
    public String template(@RequestBody() Person person) throws IOException {
        StringWriter writer = new StringWriter();
        mustache.execute(writer, person).flush();
        return writer.toString();
    }

    @RequestMapping(value = "/xml", method = RequestMethod.POST, produces = {"application/xml"})
    public String xml(@RequestBody() Person person) {
        return """
                <?xml version="1.0" encoding="UTF-8" ?>
                <Person>
                  <age>%s</age>
                  <name>%s</name>
                  <company>%s</company>
                  <email>%s</email>
                  <address>
                    <street>%s</street>
                    <city>%s</city>
                    <state>%s</state>
                    <zip>%s</zip>
                  </address>
                </Person>
                """.formatted(
                person.age, person.name, person.company, person.email,
                person.address.street, person.address.city,
                person.address.state, person.address.zip
        );
    }
}


@JacksonXmlRootElement
@JsonRootName("person")
class Person {
    public int age;
    public String name;
    public String company;
    public String email;
    public Address address;
}

class Address {
    public String street;
    public String city;
    public String state;
    public int zip;
}

XmlDemoKt.kt

package dev.dechipher.xml.xmldemo

import com.fasterxml.jackson.annotation.JsonRootName
import com.fasterxml.jackson.databind.ObjectMapper
import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlRootElement
import com.fasterxml.jackson.module.kotlin.kotlinModule
import com.github.mustachejava.DefaultMustacheFactory
import org.springframework.boot.autoconfigure.SpringBootApplication
import org.springframework.boot.runApplication
import org.springframework.context.annotation.Bean
import org.springframework.context.annotation.Primary
import org.springframework.web.bind.annotation.RequestBody
import org.springframework.web.bind.annotation.RequestMapping
import org.springframework.web.bind.annotation.RequestMethod
import org.springframework.web.bind.annotation.RestController
import java.io.StringWriter


@SpringBootApplication
@RestController
@RequestMapping(path = ["/kt/"])
class XmlDemoKt {
    companion object {
        val mustache = DefaultMustacheFactory()
            .compile("person-response.mustache")
    }

    @Bean
    @Primary
    fun objectMapper() = ObjectMapper().registerModule(kotlinModule())

    @RequestMapping(
        value = ["/serialize"],
        method = [RequestMethod.POST],
        produces = ["application/xml"]
    )
    fun serialize(@RequestBody p: PersonKt): PersonKt {
        return p.copy(name = "[Updated] ${p.name}")
    }

    @RequestMapping(
        value = ["/template"],
        method = [RequestMethod.POST],
        produces = ["application/xml"]
    )
    fun template(@RequestBody p: PersonKt): String {
        val writer = StringWriter()
        mustache.execute(writer, p).flush()
        return writer.toString()
    }


    @RequestMapping(value = ["/xml"], method = [RequestMethod.POST], produces = ["application/xml"])
    fun xml(
        @RequestBody p: PersonKt
    ): String {
        return """
    <?xml version="1.0" encoding="UTF-8" ?>
    <Person>
      <age>${p.age}</age>
      <name>${p.name}</name>
      <company>${p.company}</company>
      <email>${p.email}</email>
      <address>
            <street>${p.address.street}</street>
            <city>${p.address.city}</city>
            <state>${p.address.state}</state>
            <zip>${p.address.zip}</zip>
      </address>
    </Person>
    """.trimIndent()
    }


}

fun main(args: Array<String>) {
    runApplication<XmlDemoKt>(*args)
}

@JacksonXmlRootElement
@JsonRootName("person")
data class PersonKt(
    val age: Long,
    val name: String,
    val company: String,
    val email: String,
    val address: AddressKt
)

data class AddressKt(
    val street: String,
    val city: String,
    val state: String,
    val zip: Long
)