使用正则表达式的Java字符串拆分/解析问题

Question

I have Stream of String data which could have value

system_id "2.2.2.1"
component_id 6
sequence_number 11
timestamp 1459202982

kv {
  key "val1"
}
kv {
  key "val2"
}
kv {
  key "val3"
}

system_id "2.2.2.1"
component_id 6
sequence_number 15
timestamp 1459202982

kv {
  key "val4"
}
kv {
  key "val5"
} and so on....

All i am interested is value of key, which are val1, val2, val3....

I am using scanner as shown below,

scan = new Scanner(new File("kvfiles/file1")).useDelimiter("\\s+kv\\s+\\{\\s+");  //To ignore any thing before "kv"

while (scan.hasNext()) {
                String str = scan.next();
                finalString = str.split("\\s+\\}")[0];
}

This code is working fine when file is started with "kv {" but in above case when file is started with below mention value, parser is giving error.

    system_id "2.2.2.1"
    component_id 6
    sequence_number 11
    timestamp 1459202982

Any idea how can i skip this block of data?

Note: This block of data could come occasionally after some "kv { }" tags, all i need is to ignore it whenever it comes.

Answer 1

Why dont you take just the interesting line?

public class Test {

    public static void main(String[] args) throws FileNotFoundException {
        Pattern p = Pattern.compile("\\s+key.+");

        Scanner sc = new Scanner(new File("src/main/resources/test.txt"));
        while (sc.hasNextLine()) {
            sc.nextLine();
            String theLineYouWant = sc.findInLine(p);
            // scnn this line again here
            if (theLineYouWant != null) {
                System.out.println(theLineYouWant);
            }
        }
    }
}

Please keep in mind that the file mentioned above is just my own test file.