Java Json String extract number and replace specific text

Question

I have a text file in json, and I want to replace NumberInt(x) with the number x.

In the text file, there are records/data which is in json that has a field workYear: NumberInt(2010) as an example.

I want to replace this into workYear: 2010 by removing NumberInt( and ). This NumberInt(x) is located anywhere in text file and I want to replace all of it with its number.

I can search all the occurences of this, but I am not sure how to replace it with just the number value.

String json = <json-file-content>

String sPattern = "NumberInt\\([0-9]+\\)";
Pattern pattern = Pattern.compile(sPattern);
Matcher matcher = pattern.matcher(json);

while (matcher.find()) {
    String s = matcher.group(0);
    int workYear = Integer.parseInt(s.replaceAll("[^0-9]", ""));
    System.out.println(workYear);
}

I would like to replace all the NumberInt(x) with just the number value int json String... then I will update the text file (json file).

Thanks!

vavasthi · Accepted Answer · 2019-02-12 06:15:27Z

1

Following should work. You need to capture the tokens.

    String json = "workYear:NumberInt(2010) workYear:NumberInt(2011)";
    String sPattern = "NumberInt\\(([0-9]+)\\)";
    Pattern pattern = Pattern.compile(sPattern);
    Matcher matcher = pattern.matcher(json);

    List<String> numbers = new ArrayList<>();
    while (matcher.find()) {
        String s = matcher.group(1);
        numbers.add(s);
    }
    for (String number: numbers) {

        json = json.replaceAll(String.format("NumberInt\\(%s\\)", number), number);
    }
    System.out.println(json);

answered Feb 12, 2019 at 6:15

vavasthi

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Comments

Jos · Accepted Answer · 2019-02-12 07:00:36Z

1

You could build the output using a StringBuilder like below, Please refer to JavaDoc for appendReplacement for info on how this works.

    String s = "workYear: NumberInt(2010)\nworkYear: NumberInt(2012)";
    String sPattern = "NumberInt\\([0-9]+\\)";
    Pattern pattern = Pattern.compile(sPattern);
    Matcher matcher = pattern.matcher(s);

    StringBuilder sb = new StringBuilder();

    while (matcher.find()) {
        String s2 = matcher.group(0);
        int workYear = Integer.parseInt(s2.replaceAll("[^0-9]", ""));
        matcher.appendReplacement(sb, String.valueOf(workYear));
    }
    matcher.appendTail(sb);

    String result = sb.toString();

edited Feb 12, 2019 at 7:00

answered Feb 12, 2019 at 6:24

Jos

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2 Comments

Borgy Manotoy Over a year ago

This seems to work, but it is not using StringBuilder... only StringBuffer. Also, It stopped on line 75439 still checking why it stopped there but it did not get any error.

Jos Over a year ago

is it the last line? i added matcher.appendTail(sb); to appen any remaining text to Builder/Buffer.. Also, if input is very large, you could split by lines and do this and merge lines.

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