Get values from below string using regex in java

Question

I am a beginner to regex.

I have below String:

fail:2,success:1,fetch:1

Output Map: Get Map which contains all key-values as below:

fail - 2 (key=fail, value=2)

success - 1

fetch - 1

I have tried using below solution:

public static void main(String arg[]) {            
String msg = "fail:1,success:1,policyfetch:1"; 
System.out.println(getKeyValuesFromMsg(msg));  
}                                                  

public static Map getKeyValuesFromMsg(String msg) {
  if (msg != null) {                             
    Map keyvalues = new HashMap();             
    Pattern p = Pattern.compile("(\\w+):(,+)");
    Matcher m = p.matcher(msg);                
    while (m.find()) {                         
        keyvalues.put(m.group(1), m.group(2)); 
    }                                          
    return keyvalues;                          
} else                                         
    return Collections.emptyMap();             
}

PS Map keyvalues = new HashMap(); - usage of raw types is rather bad practice (more reading: docs.oracle.com/javase/tutorial/java/generics/rawTypes.html) — Jaroslaw Pawlak
– Jaroslaw Pawlak, Commented Jun 21, 2018 at 10:18
Your regex is wrong, m.find() returns false and your loop is never executed. — Jaroslaw Pawlak
– Jaroslaw Pawlak, Commented Jun 21, 2018 at 10:19
@KamleshKanazariya Check my answer below. If the data is as simple as you have shown in your example. You can simply use the split function — Yati Sawhney - Yates
– Yati Sawhney - Yates, Commented Jun 21, 2018 at 10:20

Yati Sawhney - Yates · Accepted Answer · 2018-06-21 10:14:54Z

2

You can use the split function, The following snippet should work fine

Map<String,String> map = new HashMap();
    String str = "fail:2,success:1,fetch:1";
    String[] keyValueParts = str.split(",");
    for(String s  : keyValueParts){
        String parts[] = s.split(":");
        map.put(parts[0],parts[1]);
    }

    System.out.println(map);

answered Jun 21, 2018 at 10:14

Yati Sawhney - Yates

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Comments

Karan · Accepted Answer · 2018-06-21 16:30:52Z

0

i would have used below method for the same.

public static void main(String arg[]) {            
    String msg = "fail:1,success:1,policyfetch:1"; 
    System.out.println(getKeyValuesFromMsg(msg));  
    }

private static Map<Object, Object> getKeyValuesFromMsg(String msg) {
    Map<Object,Object> mapObj = new HashMap<Object,Object>();
    for (int i=0;i<msg.split(",").length;i++)
    mapObj.put(msg.split(",")[i].split(":")[0],msg.split(",")[i].split(":")[1]);
    return mapObj;
}

answered Jun 21, 2018 at 16:30

Karan

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Comments

jian hu · Accepted Answer · 2018-06-21 10:45:45Z

-1

my solution:

    public static Map<String, Integer> trans2Map(String source) {
    if (null == source) {
        return Collections.emptyMap();
    }
    Map<String, Integer> result = new HashMap<>();
    Arrays.stream(source.split(","))
            .filter(pair -> pair.split(":").length == 2)
            .forEach(pair -> {
                String key = pair.split(":")[0];
                Integer value;
                try {
                    value = Integer.parseInt(pair.split(":")[1]);
                } catch (Exception e) {
                    return;
                }
                result.put(key, value);
            });
    return result;
}

edited Jun 21, 2018 at 10:45

answered Jun 21, 2018 at 10:20

jian hu

393 bronze badges

3 Comments

Jaroslaw Pawlak Over a year ago

1. Why parsing to int? OP didn't ask about it. Furthemore, if value is not a number, the map will contain null for that key. 2. check for null != pair is redundant - String#split will never return array with nulls. 3. source.isEmpty() check is redundant - your check for "contains colon" in the stream's filter will handle it. 4. Why the trim()? OP didn't ask about it either - what if the spaces matter?

jian hu Over a year ago

@ Jaroslaw Pawlak thanks for your comment： (1)、why parsing to int? this method just a demo，the map will contain null for that key(if value is not a number), really? (2)、you are right （3）、you are right （4）、 fix

Jaroslaw Pawlak Over a year ago

1. no, sorry, my bad - I missed the return; in the catch :) By the way, when using stream API you should try to make as many small operations as possible, rather than having big blocks of code. That one in forEach can be converted into map, filter, map and collect. Also, modification of variables outside the stream is not a good practice (this result.put) and you should use collectors instead.

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