Reading JSON object from txt file in Groovy

Question

I am trying to collect a JSON from a txt file. But my below code seems to keep giving me "nullPointerException".

File f = new File(tempDir+File.separator+'jsonObject.txt')
if (f){
    log.error " file exists $f"
    FileReader f2 = new FileReader(f);
    log.error " file data- $f2"
    if (f2 == null) {
        //do something
    } else {
        JsonSlurper jsonParser = new JsonSlurper();
        game = jsonParser.parse(new FileReader(f));
    }
}

SOLUTION FOUND
Reading a json txt file:

File f = new File(tempDir+File.separator+'jsonObject.txt')
def slurper = new JsonSlurper()
def jsonText = f.getText()
json = slurper.parseText( jsonText )

Writing json to a file:

File g = new File(tempDir+File.separator+'jsonObject.txt')
            g.createNewFile()
            def json = new JsonBuilder()
            json {
                "result" result
                }       
            g.setText(json.toString())

where is the null pointer being thrown? You may also want to look at this question I asked a while back around reading in text files stackoverflow.com/questions/15389329/… — andy mccullough
– andy mccullough, Commented Oct 22, 2013 at 16:05
For anyone following this, you don't need to do what the solution here says, you can read from a Reader, and writing can be done via new File( f ).text = new JsonBuilder( [ result: result ] ) rather than the 7 lines above — tim_yates
– tim_yates, Commented Oct 23, 2013 at 19:53

olyv · Accepted Answer · 2013-10-23 05:38:23Z

67

Please, try this:

import groovy.json.JsonSlurper

def inputFile = new File("D:\\yourPath\\json.txt")
def InputJSON = new JsonSlurper().parseText(inputFile.text)
InputJSON.each{ println it }

answered Oct 23, 2013 at 5:38

olyv

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1 Comment

dreamwork801 Over a year ago

With this solution, I kept getting a java.io.FileNotFoundException: and realized I needed to change new File to readFile as stated here: stackoverflow.com/a/52752719/4535181 and here stackoverflow.com/a/38679858/4535181 Additionally, I had to remove the call to the text property of inputFile

tim_yates · Accepted Answer · 2013-10-22 16:07:30Z

7

try:

File f = new File( tempDir, 'jsonObject.txt' )
if( f.exists() ) {
    def game = f.withReader { r ->
        new JsonSlurper().parse( r )
    }
    println game
}

answered Oct 22, 2013 at 16:07

tim_yates

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2 Comments

Sanket Deshpande Over a year ago

I use your code exacly, but it shows "nullPointerException" error at JsonSlurper line...

tim_yates Over a year ago

Can you add the actual stack trace to the question?

Benjamin Francisoud · Accepted Answer · 2017-11-29 09:05:04Z

1

parseFile can take a file as an input:

import groovy.json.JsonSlurper

def inputFile = new File("/your/path/my.json")
def InputJSON = new JsonSlurper().parseFile(inputFile, 'UTF-8')
InputJSON.each{ println it }

answered Nov 29, 2017 at 9:05

Benjamin Francisoud

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1 Comment

user1053510 Over a year ago

public Object parse(File file) is available in JsonSlurper since version 2.2.0 - see groovy docs

Rahul Mahadik · Accepted Answer · 2019-05-07 06:40:15Z

1

Try simple and optimized solution:

import groovy.json.JsonSlurper

try {
File inputFile = new File("your_file_path")
def slurper = new JsonSlurper()
def data = slurper.parse(inputFile)
} catch (Exception e) {
      e.printStackTrace()
    }

answered May 7, 2019 at 6:40

Rahul Mahadik

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