[Java] Class JsonSlurper

  • groovy.json.JsonSlurper

This has the same interface as the original JsonSlurper written for version 1.8.0, but its implementation has completely changed. It is now up to 20x faster than before, and its speed competes and often substantially exceeds popular common JSON parsers circa Jan, 2014.

JSON slurper parses text or reader content into a data structure of lists and maps.

Example usage: 

 def slurper = new groovy.json.JsonSlurper()
 def result = slurper.parseText('{"person":{"name":"Guillaume","age":33,"pets":["dog","cat"]}}')

 assert result.person.name == "Guillaume"
 assert result.person.age == 33
 assert result.person.pets.size() == 2
 assert result.person.pets[0] == "dog"
 assert result.person.pets[1] == "cat"
JsonSlurper can use several types of JSON parsers. Please read the documentation for JsonParserType. There are relaxed mode parsers, large file parser, and index overlay parsers. Don't worry, it is all groovy. JsonSlurper will just work, but understanding the different parser types may allow you to drastically improve the performance of your JSON parsing.

Index overlay parsers (INDEX_OVERLAY and LAX) are the fastest JSON parsers. However they are not the default for a good reason. Index overlay parsers has pointers (indexes really) to original char buffer. Care must be used if putting parsed maps into a long term cache as members of map maybe index overlay objects pointing to original buffer. You can mitigate these risks by using chop and lazy chop properties. Chop eagerly dices up the buffer so each Value element points to a small copy of the original buffer. Lazy Chop dices up the buffer when a list get or map get is called so if an GPath expression or such is applied. You do not need chop or lazy chop if you are NOT putting the map into a long term cache. You do not need chop or lazy chop if you are doing object de-serialization. Recommendation is to use INDEX_OVERLAY for JSON buffers under 2MB. The maxSizeForInMemory is set to 2MB and any file over 2MB will use a parser designed for large files, which is slower than the INDEX_OVERLAY, LAX, and CHAR_BUFFER parsers, but faster than most commonly used JSON parsers on the JVM for most use cases circa January 2014. To enable the INDEX_OVERLAY parser do this: 
             parser = new JsonSlurper().setType(JsonParserType.INDEX_OVERLAY);
See Also:
JsonParserType
Authors:
Guillaume Laforge
Rick Hightower
Since:
1.8.0

Methods Summary

Methods
Type Params Return Type Name and description
int getMaxSizeForInMemory()
Max size before Slurper starts to use windowing buffer parser.
JsonParserType getType()
Parser type.
boolean isCheckDates()
Determine if slurper will automatically parse strings it recognizes as dates.
boolean isChop()
Turns on buffer chopping for index overlay.
boolean isLazyChop()
Turns on buffer lazy chopping for index overlay.
Object parse(Reader reader)
Parse a JSON data structure from content from a reader
Object parse(InputStream inputStream)
Parse a JSON data structure from content from an inputStream
Object parse(InputStream inputStream, String charset)
Parse a JSON data structure from content from an inputStream
Object parse(byte[] bytes, String charset)
Parse a JSON data structure from content from a byte array.
Object parse(byte[] bytes)
Parse a JSON data structure from content from a byte array.
Object parse(char[] chars)
Parse a JSON data structure from content from a char array.
Object parse(File file)
Parse a JSON data structure from content within a given File.
Object parse(File file, String charset)
Parse a JSON data structure from content within a given File.
Object parse(URL url)
Parse a JSON data structure from content at a given URL.
Object parse(URL url, Map params)
Parse a JSON data structure from content at a given URL.
Object parse(Map params, URL url)
Parse a JSON data structure from content at a given URL.
Object parse(URL url, String charset)
Parse a JSON data structure from content at a given URL.
Object parse(URL url, Map params, String charset)
Parse a JSON data structure from content at a given URL.
Object parse(Map params, URL url, String charset)
Parse a JSON data structure from content at a given URL.
Object parseText(String text)
Parse a text representation of a JSON data structure
JsonSlurper setCheckDates(boolean checkDates)
Determine if slurper will automatically parse strings it recognizes as dates.
JsonSlurper setChop(boolean chop)
Turns on buffer chopping for index overlay.
JsonSlurper setLazyChop(boolean lazyChop)
Turns on buffer lazy chopping for index overlay.
JsonSlurper setMaxSizeForInMemory(int maxSizeForInMemory)
Max size before Slurper starts to use windowing buffer parser.
JsonSlurper setType(JsonParserType type)
Parser type.

Inherited Methods Summary

Inherited Methods
Methods inherited from class Name
class Object wait, wait, wait, equals, toString, hashCode, getClass, notify, notifyAll

Method Detail

public int getMaxSizeForInMemory()

Max size before Slurper starts to use windowing buffer parser.

Returns:
size of file/buffer
Since:
2.3

public JsonParserType getType()

Parser type.

Since:
2.3
See Also:
JsonParserType
Returns:
type

public boolean isCheckDates()

Determine if slurper will automatically parse strings it recognizes as dates. Index overlay only.

Returns:
on or off
Since:
2.3

public boolean isChop()

Turns on buffer chopping for index overlay.

Since:
2.3
See Also:
JsonParserType
Returns:
chop on or off

public boolean isLazyChop()

Turns on buffer lazy chopping for index overlay.

See Also:
JsonParserType
Returns:
on or off
Since:
2.3

public Object parse(Reader reader)

Parse a JSON data structure from content from a reader

Parameters:
reader - reader over a JSON content
Returns:
a data structure of lists and maps

public Object parse(InputStream inputStream)

Parse a JSON data structure from content from an inputStream

Parameters:
inputStream - stream over a JSON content
Returns:
a data structure of lists and maps
Since:
2.3

public Object parse(InputStream inputStream, String charset)

Parse a JSON data structure from content from an inputStream

Parameters:
inputStream - stream over a JSON content
charset - charset
Returns:
a data structure of lists and maps
Since:
2.3

public Object parse(byte[] bytes, String charset)

Parse a JSON data structure from content from a byte array.

Parameters:
bytes - buffer of JSON content
charset - charset
Returns:
a data structure of lists and maps
Since:
2.3

public Object parse(byte[] bytes)

Parse a JSON data structure from content from a byte array.

Parameters:
bytes - buffer of JSON content
Returns:
a data structure of lists and maps
Since:
2.3

public Object parse(char[] chars)

Parse a JSON data structure from content from a char array.

Parameters:
chars - buffer of JSON content
Returns:
a data structure of lists and maps
Since:
2.3

public Object parse(File file)

Parse a JSON data structure from content within a given File.

Parameters:
file - File containing JSON content
Returns:
a data structure of lists and maps
Since:
2.2.0

public Object parse(File file, String charset)

Parse a JSON data structure from content within a given File.

Parameters:
file - File containing JSON content
charset - the charset for this File
Returns:
a data structure of lists and maps
Since:
2.2.0

public Object parse(URL url)

Parse a JSON data structure from content at a given URL.

Parameters:
url - URL containing JSON content
Returns:
a data structure of lists and maps
Since:
2.2.0

public Object parse(URL url, Map params)

Parse a JSON data structure from content at a given URL.

Parameters:
url - URL containing JSON content
params - connection parameters
Returns:
a data structure of lists and maps
Since:
2.2.0

public Object parse(Map params, URL url)

Parse a JSON data structure from content at a given URL. Convenience variant when using Groovy named parameters for the connection params.

Parameters:
params - connection parameters
url - URL containing JSON content
Returns:
a data structure of lists and maps
Since:
2.2.0

public Object parse(URL url, String charset)

Parse a JSON data structure from content at a given URL.

Parameters:
url - URL containing JSON content
charset - the charset for this File
Returns:
a data structure of lists and maps
Since:
2.2.0

public Object parse(URL url, Map params, String charset)

Parse a JSON data structure from content at a given URL.

Parameters:
url - URL containing JSON content
params - connection parameters
charset - the charset for this File
Returns:
a data structure of lists and maps
Since:
2.2.0

public Object parse(Map params, URL url, String charset)

Parse a JSON data structure from content at a given URL. Convenience variant when using Groovy named parameters for the connection params.

Parameters:
params - connection parameters
url - URL containing JSON content
charset - the charset for this File
Returns:
a data structure of lists and maps
Since:
2.2.0

public Object parseText(String text)

Parse a text representation of a JSON data structure

Parameters:
text - JSON text to parse
Returns:
a data structure of lists and maps

public JsonSlurper setCheckDates(boolean checkDates)

Determine if slurper will automatically parse strings it recognizes as dates. Index overlay only.

Returns:
on or off
Since:
2.3

public JsonSlurper setChop(boolean chop)

Turns on buffer chopping for index overlay.

Since:
2.3
See Also:
JsonParserType
Returns:
JsonSlurper

public JsonSlurper setLazyChop(boolean lazyChop)

Turns on buffer lazy chopping for index overlay.

See Also:
JsonParserType
Returns:
JsonSlurper
Since:
2.3

public JsonSlurper setMaxSizeForInMemory(int maxSizeForInMemory)

Max size before Slurper starts to use windowing buffer parser.

Since:
2.3
Returns:
JsonSlurper

public JsonSlurper setType(JsonParserType type)

Parser type.

Since:
2.3
See Also:
JsonParserType
Returns:
JsonSlurper

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Licensed under the Apache license.
https://docs.groovy-lang.org/2.4.21/html/gapi/groovy/json/JsonSlurper.html