How to find a specific value after a specific word in Java?

Question

I got a text from a BufferedReader and I need to get a specific value in a specific string.

This is the text:

    aimtolerance = 1024;
    model = Araarrow;
    name = Bow and Arrows;
    range = 450;
    reloadtime = 3;
    soundhitclass = arrow;
    type = Ballistic;
    waterexplosionclass = small water explosion;
    weaponvelocity = 750;

        default = 213;
        fort = 0.25;
        factory = 0.25;
        stalwart = 0.25;
        mechanical = 0.5;
        naval = 0.5;

I need to get the exact number between default = and ;

Which is "213"

If you read the file into memory (into a String) you can just use string functions. — thatidiotguy, Jul 20 '12 at 15:21

score 3 · Accepted Answer · answered Jul 20 '12 at 15:27

3

Something like this....

String line;
while ((line = reader.readLine())!=null) {
   int ind = line.indexOf("default =");
   if (ind >= 0) {
      String yourValue = line.substring(ind+"default =".length(), line.length()-1).trim(); // -1 to remove de ";"
      ............
   }
}

answered Jul 20 '12 at 15:27

Ignacio A. Poletti

616
4
7

A.Poletti I tried using the above code it is throwing only -1. – Ranjan Gupta Sep 18 '18 at 13:11
@RanjanGupta maybe you have a special char in the line, because of that is not matching the indexOf – Ignacio A. Poletti Sep 18 '18 at 20:15

score 0 · Answer 2 · answered Jul 20 '12 at 15:24

If just care about the end result, i.e. getting stuff out of your '=' separated values text file, you might find the built in Properties object helpful?

http://docs.oracle.com/javase/6/docs/api/java/util/Properties.html

This does much of what you need. Of course if you're specifically wanting to do this manually, it's maybe not the right option.

score -1 · Answer 3 · edited Nov 25 '13 at 05:12

-1

Split the string on "default =" and then use indexOf to find the first occurrence of ";". Do a substring from 0 to the index and you have your value.

See http://docs.oracle.com/javase/7/docs/api/java/lang/String.html

edited Nov 25 '13 at 05:12

Afshin Moazami

2,092
5
33
55

answered Jul 20 '12 at 15:23

DeweyOx

719
5
14

ᴇʟᴇvᴀтᴇ · Answer 4 · 2015-01-28T17:09:47.100

-1

Using regular expressions:

private static final Pattern DEFAULT_VALUE_PATTERN
        = Pattern.compile("default = (.*?);");

private String extractDefaultValueFrom(String text) {
    Matcher matcher = DEFAULT_VALUE_PATTERN.matcher(text);
    if (!matcher.find()) {
        throw new RuntimeException("Failed to find default value in text");
    }
    return matcher.group(1);
}

edited Jan 28 '15 at 17:09

answered Jul 20 '12 at 15:44

ᴇʟᴇvᴀтᴇ

12,285
4
43
66

score -1 · Answer 5 · answered Jul 21 '12 at 17:50

you can use Properties class to load the string and find any value from it

String readString = "aimtolerance = 1024;\r\n" + 
"model = Araarrow;\r\n" + 
"name = Bow and Arrows;\r\n" + 
"range = 450;\r\n" + 
"reloadtime = 3;\r\n" + 
"soundhitclass = arrow;\r\n" + 
"type = Ballistic;\r\n" + 
"waterexplosionclass = small water explosion;\r\n" + 
"weaponvelocity = 750;\r\n" + 
"default = 213;\r\n" + 
"fort = 0.25;\r\n" + 
"factory = 0.25;\r\n" + 
"stalwart = 0.25;\r\n" + 
"mechanical = 0.5;\r\n" + 
"naval = 0.5;\r\n";
readString = readString.replaceAll(";", "");
Properties properties = new Properties();

System.out.println(properties);
try {
    properties.load(new StringReader(readString));
} catch (IOException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}
System.out.println(properties);

String requiredPropertyValue = properties.getProperty("default");
System.out.println("requiredPropertyValue : "+requiredPropertyValue);

How to find a specific value after a specific word in Java?

5 Answers5

Linked