json-data-generator

json-data-generator helps you build json data that you need for test data purposes. It has a lot of nice features that you can use to build as much test data as you need.

Maven

Add a dependency to com.github.vincentrussell:json-data-generator.

<dependency>
   <groupId>com.github.vincentrussell</groupId>
   <artifactId>json-data-generator</artifactId>
   <version>1.16</version>
</dependency>

Requirements

• JDK 1.8 or higher
• Apache Maven 3.1.0 or higher

Running it from Java

JsonDataGeneratorImpl parser = new JsonDataGeneratorImpl();
parser.generateTestDataJson(String text, OutputStream outputStream);

or

JsonDataGeneratorImpl parser = new JsonDataGeneratorImpl();
parser.generateTestDataJson(URL classPathResource, OutputStream outputStream);

or

JsonDataGeneratorImpl parser = new JsonDataGeneratorImpl();
parser.generateTestDataJson(File file, OutputStream outputStream);

or

JsonDataGeneratorImpl parser = new JsonDataGeneratorImpl();
parser.generateTestDataJson(InputStream inputStream, OutputStream outputStream);

Running it as a standalone jar

java -jar json-data-generator-1.16-standalone.jar -s source.json -d destination.json

Options

usage: [-s <arg>] [-d
       <arg>] [-f <arg>] [-i] [-t <arg>]
 -s,--sourceFile <arg>        the source file.
 -d,--destinationFile <arg>   the destination file.  Defaults to
                              System.out
 -f,--functionClasses <arg>   additional function classes that are on the
                              classpath and should be loaded
 -i,--interactiveMode         interactive mode
 -p,--pipeMode                pipe mode
 -t,--timeZone <arg>          default time zone to use when dealing with dates

Example

{
    "id": "{{uuid()}}",
    "name": "A green door",
    "age": {{integer(1,50)}},
    "price": 12.50,
    "tags": ["home", "green"]
}

pipeMode

cat putGetTest.json | java -jar json-data-generator-1.16.standalone.jar -p | jq  .code.rgba | jq length

Repeats

You can repeat sections of json to make repeating json objects.

For instance you can do repeats like this:

[
    '{{repeat(2)}}',
    {
        "id": "{{uuid()}}",
        "name": "Test",
        "attributes": [
            '{{repeat(2)}}',
            {
                "shirt": "{{random("red","yellow","green")}}",
                "pants": "{{random("blue","black","orange")}}"
            }
        ]

    }
]

You can also get a random repeat within a range like this:

'{{repeat(2,9)}}',

You can have a repeat not occur possibly by having 0 in the low end of the range:

'{{repeat(0,9)}}',

You can have a repeat based on a system property:

'{{repeat(systemProperty('lowerRange'),systemProperty('upperRange'))}}',

Available functions

You can do a lot of cool functions in your puesdo json that that help you randomize your test data.

random integer in range:

{{integer(min,max)}}

random float in range (with optional format):

{{float(min,max)}}

{{float(min,max,"%.2f")}}

random double in range (with optional format):

{{double(min,max)}}

{{double(min,max,"%.2f")}}

random long in range:

{{long(min,max)}}

uuid:

{{uuid()}}

uuid without dashes:

{{uuid("false")}}

hex (16 bytes):

{{hex()}}

hex (with byte size):

{{hex(size)}}

objectId (12 byte hex string):

{{objectId()}}

random boolean:

{{bool()}}

random boolean with given probability:

{{bool(0.9)}}

an incrementing index integer

{{index()}}

a named incrementing index integer

{{index("index-name")}}

an incrementing index integer with a specific starting point

{{index(78)}}

an incrementing index integer with a name and a specific starting point

{{index("index-name",78)}

reset the default index

{{resetIndex("inner")}}

reset an index with name (more detailed example)

[
  '{{repeat(3)}}',
  {
    index: '{{index("outer")}}',
    friends: [
      '{{repeat(3)}}',
      {
        id: '{{index("inner")}}',
        name: 'nameValue'{{resetIndex("inner")}}
      }
    ],
}
]

lorem ipsum words:

{{lorem(count,"words")}}

lorem ipsum paragraphs:

{{lorem(count,"paragraphs")}}

random phone number:

{{phone()}}

random gender (male or female):

{{gender()}}

current time (default format is: "h[:mm][ ]a"):

{{time()}}

current time with the time format specified:

{{time("HH:mm:ss")}}

random time between two times and the output format specified. The input format must be "h[:mm][ ]a":

{{time("6:05PM", "6:07PM", "HH:mm:ss")}}

current date date (default format is: EEE, d MMM yyyy HH:mm:ss z):

{{date()}}

current date with format:

{{date("output-java-simple-date-format")}}

random date between two dates with format (your input must be in this format dd-MM-yyyy HH:mm:ss):

{{date("begin-date","end-date","output-java-simple-date-format")}}

random date between two dates with format for input and output (both your start date and end date must be in the same format):

{{date("begin-date","end-date","input-java-simple-date-format","output-java-simple-date-format")}}

random date between two dates with default format (your input must be in this format EEE, d MMM yyyy HH:mm:ss z):

{{date("begin-date","end-date")}}

convert date format from one format to another:

{{dateFormat("06-16-1956 12:00:00", "from-simple-date-format", "to-simple-date-format")}}

current timestamp (milliseconds, between the current time and midnight, January 1, 1970 UTC):

{{timestamp()}}

random timestamp (milliseconds since midnight, January 1, 1970 UTC) between two dates with default format (your input must be in this format dd-MM-yyyy HH:mm:ss):

{{timestamp("begin-date","end-date")}}

current timestamp (seconds, between the current time and midnight, January 1, 1970 UTC):

{{timestampSeconds()}}

random timestamp (seconds since midnight, January 1, 1970 UTC) between two dates with default format (your input must be in this format EEE, d MMM yyyy HH:mm:ss z):

{{timestampSeconds("begin-date","end-date")}}

random country:

{{country()}}

add (or subtract) days to date with format:

{{addDays("dd-MM-yyyy HH:mm:ss", "03-11-2018 09:27:56", 12)}}

add (or subtract) days to date with default input format:

{{addDays("03-11-2018 09:27:56", 12)}}

add (or subtract) hours to date with format:

{{addHours("dd-MM-yyyy HH:mm:ss", "03-11-2018 09:27:56", 12)}}

add (or subtract) hours to date with default input format:

{{addHours("03-11-2018 09:27:56", 12)}}

add (or subtract) minutes to date with format:

{{addMinutes("dd-MM-yyyy HH:mm:ss", "03-11-2018 09:27:56", 12)}}

add (or subtract) minutes to date with default input format:

{{addMinutes("03-11-2018 09:27:56", 12)}}

add (or subtract) months to date with format:

{{addMonths("dd-MM-yyyy HH:mm:ss", "03-11-2018 09:27:56", 12)}}

add (or subtract) months to date with default input format:

{{addMonths("03-11-2018 09:27:56", 12)}}

add (or subtract) seconds to date with format:

{{addSeconds("dd-MM-yyyy HH:mm:ss", "03-11-2018 09:27:56", 12)}}

add (or subtract) seconds to date with default input format:

{{addSeconds("03-11-2018 09:27:56", 12)}}

add (or subtract) weeks to date with format:

{{addWeeks("dd-MM-yyyy HH:mm:ss", "03-11-2018 09:27:56", 12)}}

add (or subtract) weeks to date with default input format:

{{addWeeks("03-11-2018 09:27:56", 12)}}

add (or subtract) years to date with format:

{{addYears("dd-MM-yyyy HH:mm:ss", "03-11-2018 09:27:56", 12)}}

add (or subtract) years to date with default input format:

{{addYears("03-11-2018 09:27:56", 12)}}

convert date to timestamp with date format:

{{toTimestamp("03-11-2018 09:27:56", "dd-MM-yyyy HH:mm:ss")}}

convert date to timestamp with defaultFormat:

{{toTimestamp("Sat, 12 Feb 2022 21:01:21 GMT")}}

convert date to timestamp in seconds format with date format:

{{toTimestampSeconds("03-11-2018 09:27:56", "dd-MM-yyyy HH:mm:ss")}}

convert date to timestamp in seconds format with defaultFormat:

{{toTimestampSeconds("Sat, 12 Feb 2022 21:01:21 GMT")}}

a json mapping with all country codes to mappings:

{{countryList()}}

a json mapping with just specified country codes to mappings:

{"IN":"India","US":"United States","UK":"United Kingdom"}

{{countryList("IN", "US", "UK")}}

random city:

{{city()}}

random state:

{{state()}}

random company:

{{company()}}

random lastname:

{{lastName()}}

random first name:

{{firstName()}}

random username based on first initial from random first name and lastname lowercased:

{{username()}}

random email:

{{email()}}

random email with domain:

{{email("mydomain.com")}}

random social security number:

{{ssn()}}

random ipv4:

{{ipv4()}}

random ipv6:

{{ipv6()}}

random ipv6 (uppercase):

{{ipv6("upper")}}

random ipv6 (lowercase):

{{ipv6("lower")}}

concat (var arg):

{{concat("A","B","C","D")}}

substring:

{{substring("word",3)}}

{{substring("long word", 1, 6)}}

random item from list:

{{random("red","yellow","green")}}

random string with alphabetic characters (defaults to between 10 and 20 characters):

{{alpha()}}

{{alpha(min,max)}}

{{alpha(length)}}

random string with alpha-numeric characters (defaults to between 10 and 20 characters):

{{alphaNumeric()}}

{{alphaNumeric(min,max)}}

{{alphaNumeric(length)}}

lower case a string:

{{toLowerCase("red")}}

upper case a string:

{{toUpperCase("red")}}

put a value in the cache:

{{put("key", "VALUE")}}

retrieve a value from the cache:

{{get("key")}}

retrieve a value from a system property:

{{systemProperty("property")}}

regexify (defaults to en-US local)... build string based on regex:

{{regexify("[a-z1-9]{10}")}}

regexify with local:

{{regexify("en-GB", "[a-z1-9]{10}")}}

Escape braces

If you want to escape braces from within a function use a single escape character as seen in the example below:

{{concat("\{", "test", "\}")}}

XML support

<?xml version="1.0" encoding="UTF-8"?>
<root>
  '{{repeat(2)}}',
  <element>
    <id>{{guid()}}</id>
	<name>{{firstName()}}</name>
    <index>{{lastName()}}</index>
  </element>

<tags>
      '{{repeat(7)}}',
      {{lorem(1, "words")}}
</tags>
<friends>
      '{{repeat(3)}}',
	  <friend>
        <id>{{index()}}</id>
        <name>{{firstName()}} {{surname()}}</name>
	</friend>
</friends>
</root>

Nesting functions

json-data-generator supports nesting functions as well.

For example, if you wanted to create results that looked like dollar amounts you could do something like:

{{concat("$",float(0.90310, 5.3421, "%.2f"))}}

or something like this if you wanted a capitalized F or M:

{{toUpperCase(substring(gender(),0,1))}}

Use of put and get functions

The get and put functions can be used to use previously-used values later on in the document. The put function returns the value passed into it. See the following example.

{
  "firstName": "{{put("firstName", firstName())}}",
  "lastName": "{{put("lastName", lastName())}}",
  "email": "{{get("firstName")}}.{{get("lastName")}}@mydomain.com"
}

produces

{
  "firstName": "Eve",
  "lastName": "Acosta",
  "email": "[email protected]"
}

Use date add functions

The date add functions can be used in conjuction with the get and put functions to create new date values by adding (or subtracting)

{
    "day1": "{{put("date", date("dd-MM-yyyy HH:mm:ss"))}}",
    "day2": "{{addDays(get("date"), 12)}}"
}

produces

{
    "day1": "03-11-2018 09:27:56",
    "day2": "15-11-2018 09:27:56"
}

Creating Custom Functions

You can also create new functions if you create the classes and register the function with the function registry.

-When you create Functions you must annotate the class with the @Function annotation and you must specify one or more names for the function. -Use the @FunctionInvocation annotation to indicate the method that will be executed when the function is called. The arguments of the function must be strings (or a Vararg String argument) and the method must return a string.

package my.package;

import com.github.vincentrussell.json.datagenerator.functions.Function;
import com.github.vincentrussell.json.datagenerator.functions.FunctionInvocation;

import java.util.Random;

@Function(name = "new-function")
public class NewFunction {

    private static final Random RANDOM = new Random();

    @FunctionInvocation
    public String getRandomInteger(String min, String max) {
        return getRandomInteger(Integer.parseInt(min), Integer.parseInt(max));
    }

    private String getRandomInteger(Integer min, Integer max) {
        int randomNumber = RANDOM.nextInt(max - min) + min;
        return Integer.toString(randomNumber);
    }
}

then you can put the jar that you have created on the classpath with the the standalone jar (-f registers one or more classes with the Function Registry):

java -cp json-data-generator-1.16-standalone.jar:yourfunctions.jar com.github.vincentrussell.json.datagenerator.CLIMain -s source.json -d destination.json -f my.package.NewFunction

Or you add json-data-generator as a dependency to your application you can simply add your function to the registry like this:

FunctionRegistry functionRegistry = new FunctionRegistry(); 
functionRegistry.registerClass(Customer.class);
JsonDataGenerator jsonDataGenerator = new JsonDataGeneratorImpl(functionRegistry);

Change Log

1.16 (2022-06-04)

Improvements:

• created systemProperty function
• repeats are now functions so it can support nested functions

1.15 (2022-05-22)

Improvements:

• created timeStampSeconds function
• added the ability to convert dates to timestamp via toTimestampSeconds function
• added the ability to pass in a particular input format for date function
• added time function

Change Log

1.14 (2022-02-12)

Improvements:

• added -p for pipeMode to be used with unix pipes
• added the ability to convert dates to timestamp via toTimestamp function

1.13 (2021-08-28)

Improvements:

• removing statics associated with FunctionRegistry to provide multithreaded support.

1.12 (2021-02-15)

Bugs:

• fix overflow error in ByteArrayBackupToFileOutputStream

1.11 (2020-11-03)

Improvements:

• allow repeat ranges with zero
• changed repeat ranges to be inclusive

1.10 (2020-07-19)

Improvements:

• upgrade ph-javacc-maven-plugin to 4.1.4
• added the regexify function

1.9 (2019-01-01)

Bugs:

• random double function now supports a format
• index values can be reset to their starting point with resetIndex function

1.8 (2018-12-01)

Bugs:

• String arguments for functions can be single or double-quoted

1.7 (2018-11-05)

Improvements:

• Added the ability to generate a uuid without dashes.
• Added the abiilty to add or subtract days, hours, mintues, months, seconds, and years to dates
• Added dateFormat function
• Added UTF-8 international character support

1.6 (2018-10-08)

Improvements:

• Added put and get functions to allow to reference values later that had been stored previously
• Upgraded guava to version 25.0-jre
• Upgraded java compile version to java 1.8

1.5 (2018-07-31)

Improvements:

• Adding boolean with probability support
• Adding the ability to provide a domain to the email function
• Added the ability to escape brackets within functions so that the interperter can understand that the function and wont return early
• Added a hex function
• Added a countryList function

1.4.1 (2018-07-15)

Bugs:

• Added check for invalid scenarios to avoid going in infinite loop

1.4 (2018-06-25)

Improvements:

• Created username function
• Added XML support

Change Log

1.3 (2017-02-04)

Improvements:

• Changed index function to be based on a String key not it's level of nesting to reduce complexity
• Changed index function to allow for an integer to start at.

Change Log

1.2 (2016-04-10)

Improvements:

• Standalone interactive mode
• The ability to specify a timezone in standalone mode
• New timestamp function
• New alpha function
• New alphaNumeric function

1.1 (2016-03-20)

Improvements:

• Repeats can be randomized between a range of two integers
• Multiple names can be used in the @Function annotation provide multiple functions in the json mapping to the same name
• Created objectId (12 byte hex string) function

Bugs:

• Floating point numbers can be parsed and used in fuctions
• Repeats can be used with functions surrounded in strings, like '{{lorem(1, "words")}}'