Groovy Documentation

## groovy.json
[Groovy] Class JsonBuilder

    java.lang.Object
      groovy.json.JsonBuilder

All Implemented Interfaces:
  Writable

    class JsonBuilder

A builder for creating JSON payloads.

This builder supports the usual builder syntax made of nested method calls and closures, but also some specific aspects of JSON data structures, such as list of values, etc. Please make sure to have a look at the various methods provided by this builder to be able to learn about the various possibilities of usage.

Example:

           def builder = new groovy.json.JsonBuilder()
           def root = builder.people {
               person {
                   firstName 'Guillame'
                   lastName 'Laforge'
                   // Named arguments are valid values for objects too
                   address(
                           city: 'Paris',
                           country: 'France',
                           zip: 12345,
                   )
                   married true
                   // a list of values
                   conferences 'JavaOne', 'Gr8conf'
               }
           }

           // creates a data structure made of maps (Json object) and lists (Json array)
           assert root instanceof Map

           assert builder.toString() == '{"people":{"person":{"firstName":"Guillame","lastName":"Laforge","address":{"city":"Paris","country":"France","zip":12345},"married":true,"conferences":["JavaOne","Gr8conf"]}}}'

Authors:
  Guillaume Laforge

Since:
  1.8.0

Property Summary
`java.lang.Object` | `content` Resulting data structure made of lists and maps, representing a JSON payload

Constructor Summary
`JsonBuilder(java.lang.Object content = null)` Instanciates a JSON builder, possibly with some existing data structure.

Method Summary
`java.lang.Object` | `call(java.util.Map m)` Named arguments can be passed to the JSON builder instance to create a root JSON object
`java.lang.Object` | `call(java.util.List l)` A list of elements as arguments to the JSON builder creates a root JSON array
`java.lang.Object` | `call(java.lang.Object... args)` Varargs elements as arguments to the JSON builder create a root JSON array
`java.lang.Object` | `call(Closure c)` A closure passed to a JSON builder will create a root JSON object
`java.lang.Object` | `invokeMethod(java.lang.String name, java.lang.Object args)` A method call on the JSON builder instance will create a root object with only one key whose name is the name of the method being called.
`java.lang.String` | `toPrettyString()` Pretty-prints and formats the JSON payload.
`java.lang.String` | `toString()` Serializes the internal data structure built with the builder to a conformant JSON payload string
`java.io.Writer` | `writeTo(java.io.Writer out)` The JSON builder implements the `Writable` interface, so that you can have the builder serialize itself the JSON payload to a writer.

Methods inherited from class java.lang.Object
java.lang.Object#wait(long), java.lang.Object#wait(long, int), java.lang.Object#wait(), java.lang.Object#equals(java.lang.Object), java.lang.Object#toString(), java.lang.Object#hashCode(), java.lang.Object#getClass(), java.lang.Object#notify(), java.lang.Object#notifyAll()

Property Detail

### content

    java.lang.Object content

  Resulting data structure made of lists and maps, representing a JSON payload

Constructor Detail

### JsonBuilder

    JsonBuilder(java.lang.Object content = null)

  Instanciates a JSON builder, possibly with some existing data structure.
  Parameters:
    `content` - a pre-existing data structure, default to null

Method Detail

### call

    java.lang.Object call(java.util.Map m)

  Named arguments can be passed to the JSON builder instance to create a root JSON object

  Example:

       def json = new JsonBuilder()
       json name: "Guillaume", age: 33

       assert json.toString() == '{"name":"Guillaume","age":33}'

  Parameters:
    `m` - a map of key / value pairs
  Returns:
    a map of key / value pairs

### call

    java.lang.Object call(java.util.List l)

  A list of elements as arguments to the JSON builder creates a root JSON array

  Example:

       def json = new JsonBuilder()
       def result = json([1, 2, 3])

       assert result instanceof List
       assert json.toString() == "[1,2,3]"

  Parameters:
    `l` - a list of values
  Returns:
    a list of values

### call

    java.lang.Object call(java.lang.Object... args)

  Varargs elements as arguments to the JSON builder create a root JSON array

  Example:

       def json = new JsonBuilder()
       def result = json 1, 2, 3

       assert result instanceof List
       assert json.toString() == "[1,2,3]"

  Parameters:
    `args` - an array of values
  Returns:
    a list of values

### call

    java.lang.Object call(Closure c)

  A closure passed to a JSON builder will create a root JSON object

  Example:

       def json = new JsonBuilder()
       def result = json {
            name "Guillaume"
            age 33
       }

       assert result instanceof Map
       assert json.toString() == '{"name":"Guillaume","age":33}'

  Parameters:
    `c` - a closure whose method call statements represent key / values of a JSON object
  Returns:
    a map of key / value pairs

### invokeMethod

    java.lang.Object invokeMethod(java.lang.String name, java.lang.Object args)

  A method call on the JSON builder instance will create a root object with only one key whose name is the name of the method being called. This method takes as arguments:
  - a closure
  - a map (ie. named arguments)
  - a map and a closure
  - or no argument at all

  Example with a classicala builder-style:

       def json = new JsonBuilder()
       def result = json.person {
            name "Guillaume"
            age 33
       }

       assert result instanceof Map
       assert json.toString() == '{"person":{"name":"Guillaume","age":33}}'

  Or alternatively with a method call taking named arguments:

       def json = new JsonBuilder()
       json.person name: "Guillaume", age: 33

       assert json.toString() == '{"person":{"name":"Guillaume","age":33}}'

  If you use named arguments and a closure as last argument, the key/value pairs of the map (as named arguments) and the key/value pairs represented in the closure will be merged together — the closure properties overriding the map key/values in case the same key is used.

       def json = new JsonBuilder()
       json.person(name: "Guillaume", age: 33) { town "Paris" }

       assert json.toString() == '{"person":{"name":"Guillaume","age":33,"town":"Paris"}}'

  The empty args call will create a key whose value will be an empty JSON object:

       def json = new JsonBuilder()
       json.person()

       assert json.toString() == '{"person":{}}'

  Parameters:
    `name` - the single key
    `args` - the value associated with the key
  Returns:
    a map with a single key

### toPrettyString

    java.lang.String toPrettyString()

  Pretty-prints and formats the JSON payload.

  This method calls the JsonLexer to parser the output of the builder, so this may not be an optimal method to call, and should be used mainly for debugging purpose for a human-readable output of the JSON content.

  Returns:
    a pretty printed JSON output

### toString

    java.lang.String toString()

  Serializes the internal data structure built with the builder to a conformant JSON payload string

  Example:

       def json = new JsonBuilder()
       json { temperature 37 }

       assert json.toString() == '{"temperature":37}'

  Returns:
    a JSON output

### writeTo

    java.io.Writer writeTo(java.io.Writer out)

  The JSON builder implements the `Writable` interface, so that you can have the builder serialize itself the JSON payload to a writer.

  Example:

       def json = new JsonBuilder()
       json { temperature 37 }

       def out = new StringWriter()
       out << json

       assert out.toString() == '{"temperature":37}'

  Parameters:
    `out` - a writer on which to serialize the JSON payload
  Returns:
    the writer

Groovy Documentation