In this section, we will explore how to work with XML and JSON data in Groovy. These are common data formats used for configuration, data exchange, and storage. Groovy provides powerful and easy-to-use libraries to handle both XML and JSON.

1. Introduction to XML and JSON
2. Parsing XML
3. Generating XML
4. Parsing JSON
5. Generating JSON
6. Practical Exercises
7. Summary

• Structure: Hierarchical, tag-based format.
• Usage: Commonly used for configuration files, data interchange, and document storage.
• Example:

  <person>
      <name>John Doe</name>
      <age>30</age>
  </person>
  

• Structure: Key-value pairs, array-based format.
• Usage: Widely used for APIs, configuration files, and data interchange.
• Example:

  {
      "name": "John Doe",
      "age": 30
  }
  

Groovy provides the XmlSlurper and XmlParser classes for parsing XML.

• Example:

  def xml = '''
  <person>
      <name>John Doe</name>
      <age>30</age>
  </person>
  '''
  def person = new XmlSlurper().parseText(xml)
  println "Name: ${person.name.text()}"
  println "Age: ${person.age.text()}"
  

• Explanation:
  • XmlSlurper is used to parse the XML string.
  • parseText method parses the XML content.
  • Accessing elements is straightforward using dot notation.

• Example:

  def xml = '''
  <person>
      <name>John Doe</name>
      <age>30</age>
  </person>
  '''
  def person = new XmlParser().parseText(xml)
  println "Name: ${person.name.text()}"
  println "Age: ${person.age.text()}"
  

• Explanation:
  • XmlParser is another way to parse XML.
  • Similar to XmlSlurper, but provides a more DOM-like structure.

Groovy's MarkupBuilder class is used to generate XML.

• Example:

  def writer = new StringWriter()
  def xml = new groovy.xml.MarkupBuilder(writer)
  xml.person {
      name 'John Doe'
      age 30
  }
  println writer.toString()
  

• Explanation:
  • MarkupBuilder is used to create XML content.
  • The XML structure is defined using a builder pattern.

Groovy provides the JsonSlurper class for parsing JSON.

• Example:

  def json = '''
  {
      "name": "John Doe",
      "age": 30
  }
  '''
  def person = new groovy.json.JsonSlurper().parseText(json)
  println "Name: ${person.name}"
  println "Age: ${person.age}"
  

• Explanation:
  • JsonSlurper is used to parse the JSON string.
  • parseText method parses the JSON content.
  • Accessing elements is done using dot notation.

Groovy's JsonBuilder class is used to generate JSON.

• Example:

  def builder = new groovy.json.JsonBuilder()
  builder.person {
      name 'John Doe'
      age 30
  }
  println builder.toPrettyString()
  

• Explanation:
  • JsonBuilder is used to create JSON content.
  • The JSON structure is defined using a builder pattern.
  • toPrettyString method formats the JSON output.

• Task: Parse the following XML and print the name and age.

  <person>
      <name>Jane Doe</name>
      <age>25</age>
  </person>
  

• Solution:

  def xml = '''
  <person>
      <name>Jane Doe</name>
      <age>25</age>
  </person>
  '''
  def person = new XmlSlurper().parseText(xml)
  println "Name: ${person.name.text()}"
  println "Age: ${person.age.text()}"
  

• Task: Generate JSON for a person with name "Alice" and age 28.
• Solution:

  def builder = new groovy.json.JsonBuilder()
  builder.person {
      name 'Alice'
      age 28
  }
  println builder.toPrettyString()
  

In this section, we covered:

• The basics of XML and JSON.
• How to parse XML using XmlSlurper and XmlParser.
• How to generate XML using MarkupBuilder.
• How to parse JSON using JsonSlurper.
• How to generate JSON using JsonBuilder.

Understanding how to work with XML and JSON is crucial for many programming tasks, including configuration management, data interchange, and API development. In the next section, we will explore database access in Groovy.