How to split a string from a file in Java

Question

I have a line in a file.txt, |a|b|c|d|, that I want to extract the values between | (result a,b,c,d) How can I do this?

Answer 1

From String[] split(String regex)

Splits this string around matches of the given regular expression. This method works as if by invoking the two-argument split method with the given expression and a limit argument of zero. Trailing empty strings are therefore not included in the resulting array.

The string "boo:and:foo", for example, yields the following results with these expressions:

Regex Result
: { "boo", "and", "foo" }
o { "b", "", ":and:f" }

Use following code:

String[] arr = "|a|b|c|d|".split("\\|");

Answer 2

The pipe (|) is a special character in regular expression language (the split method takes a regular expression as a parameter), and thus needs to be escaped.

You will need to use something like so: String[] str = "|a|b|c|d|".split("\\|");

Given this:

 String[] str = "|a|b|c|d|".split("\\|");
    for(String string : str)
        System.out.println(string);

Will yield:

  //The first string will be empty, since your string starts with a pipe.
a
b
c
d

Answer 3

public static void main(String[] args) throws IOException {

    FileReader fr = new FileReader(new File(
            "file.txt"));
    BufferedReader br = new BufferedReader(fr);
    String st;
    StringBuffer sb = new StringBuffer();
    st = br.readLine();
    if (st != null) {
        StringTokenizer strTkn = new StringTokenizer(st, "|");
        while (strTkn.hasMoreElements()) {
            sb.append(strTkn.nextElement());
        }
    }

    System.out.println(sb);

}