- Groovy 2 Cookbook
- Table of Contents
- Groovy 2 Cookbook
- Credits
- About the Authors
- About the Reviewers
- www.PacktPub.com
- Preface
- 1. Getting Started with Groovy
- Introduction
- Installing Groovy on Windows
- Installing Groovy on Linux and OS X
- Executing Groovy code from the command line
- Using Groovy as a command-line text file editor
- Using Groovy to start a server on the command line
- Running Groovy with invokedynamic support
- Building Groovy from source
- Managing multiple Groovy installations on Linux
- Using groovysh to try out Groovy commands
- Starting groovyConsole to execute Groovy snippets
- Configuring Groovy in Eclipse
- Configuring Groovy in IntelliJ IDEA
- 2. Using Groovy Ecosystem
- Introduction
- Using Java classes from Groovy
- Embedding Groovy into Java
- Compiling Groovy code
- Simplifying dependency management with Grape
- Integrating Groovy into the build process using Ant
- Integrating Groovy into the build process using Maven
- Integrating Groovy into the build process using Gradle
- Generating documentation for Groovy code
- Checking Groovy code's quality with CodeNarc
- 3. Using Groovy Language Features
- Introduction
- Searching strings with regular expressions
- Writing less verbose Java Beans with Groovy Beans
- Inheriting constructors in Groovy classes
- Adding the cloning functionality to Groovy Beans
- Defining code as data in Groovy
- Defining data structures as code in Groovy
- Implementing multiple inheritance in Groovy
- Adding a functionality to the existing Java/Groovy classes
- Defining type-checking rules for dynamic code
- Adding automatic logging to Groovy classes
- 4. Working with Files in Groovy
- Introduction
- Reading from a file
- Reading a text file line by line
- Processing every word in a text file
- Writing to a file
- Replacing tabs with spaces in a text file
- Filtering a text file's content
- Deleting a file or directory
- Walking through a directory recursively
- Searching for files
- Changing file attributes on Windows
- Reading data from a ZIP file
- Reading an Excel file
- Extracting data from a PDF
- 5. Working with XML in Groovy
- 6. Working with JSON in Groovy
- 7. Working with Databases in Groovy
- Introduction
- Creating a database table
- Connecting to an SQL database
- Querying an SQL database
- Modifying data in an SQL database
- Calling a stored procedure
- Reading BLOB/CLOB from a database
- Building a simple ORM framework
- Using Groovy to access Redis
- Using Groovy to access MongoDB
- Using Groovy to access Apache Cassandra
- 8. Working with Web Services in Groovy
- Introduction
- Downloading content from the Internet
- Executing an HTTP GET request
- Executing an HTTP POST request
- Constructing and modifying complex URLs
- Issuing a REST request and parsing a response
- Issuing a SOAP request and parsing a response
- Consuming RSS and Atom feeds
- Using basic authentication for web service security
- Using OAuth for web service security
- 9. Metaprogramming and DSLs in Groovy
- Introduction
- Querying methods and properties
- Dynamically extending classes with new methods
- Overriding methods dynamically
- Adding performance logging to methods
- Adding a caching functionality around methods
- Adding transparent imports to a script
- DSL for executing commands over SSH
- DSL for generating reports from logfiles
- 10. Concurrent Programming in Groovy
- Introduction
- Processing collections concurrently
- Downloading files concurrently
- Splitting a large task into smaller parallel jobs
- Running tasks in parallel and asynchronously
- Using actors to build message-based concurrency
- Using STM to atomically update fields
- Using dataflow variables for lazy evaluation
- Index
In this chapter, we will cover:
- Parsing JSON messages with JsonSlurper
- Constructing JSON messages with JsonBuilder
- Modifying JSON messages
- Validating JSON messages
- Converting JSON message to XML
- Converting JSON message to Groovy Bean
- Using JSON to configure your scripts
JSON (JavaScript Object Notation) (http://www.json.org/) is a data interchange format, similar in scope to XML or CSV. It uses a very lightweight serialization form and works very well for exchanging data between a web client (a browser) and a remote server, but it is not limited to only that.
JSON is also a subset of the object literal notation of JavaScript. Being a subset of JavaScript implies that a JSON payload can be processed by the language natively. This is the main reason why JSON has become such a popular format for transferring serialized data between a remote API (often a RESTful API) and a JavaScript client.
But JSON is also very lightweight—especially if we compare it to the very chatty XML, the dethroned king of serialization—making it a suitable candidate for a general purpose data processing format (if you can live with some of its limitations such as the lack of namespace or poor complex data types support).
This chapter's recipes introduce the reader to Groovy native support for reading and producing JSON. We also look at some more advanced recipes such as conversion from and to XML and Groovy Beans.
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