String delimiter in string.split method

问题

I have following data:

1||1||Abdul-Jabbar||Karim||1996||1974

I want to delimit the tokens.

Here the delimiter is "||".

My delimiter setter is:

public void setDelimiter(String delimiter) {
    char[] c = delimiter.toCharArray();
    this.delimiter = "\"" + "\\" + c[0] + "\\" + c[1] + "\"";
    System.out.println("Delimiter string is: " + this.delimiter);
}

However,

String[] tokens = line.split(delimiter);

is not giving the required result.

回答1:

There is no need to set the delimiter by breaking it up in pieces like you have done.

Here is a complete program you can compile and run:

import java.util.Arrays;
public class SplitExample {
    public static final String PLAYER = "1||1||Abdul-Jabbar||Karim||1996||1974";
    public static void main(String[] args) {
        String[] data = PLAYER.split("\\|\\|");
        System.out.println(Arrays.toString(data));
    }
}

If you want to use split with a pattern, you can use Pattern.compile or Pattern.quote.

To see compile and quote in action, here is an example using all three approaches:

import java.util.Arrays;
import java.util.regex.Pattern;
public class SplitExample {
    public static final String PLAYER = "1||1||Abdul-Jabbar||Karim||1996||1974";
    public static void main(String[] args) {
        String[] data = PLAYER.split("\\|\\|");
        System.out.println(Arrays.toString(data));

        Pattern pattern = Pattern.compile("\\|\\|");
        data = pattern.split(PLAYER);
        System.out.println(Arrays.toString(data));

        pattern = Pattern.compile(Pattern.quote("||"));
        data = pattern.split(PLAYER);
        System.out.println(Arrays.toString(data));
    }
}

The use of patterns is recommended if you are going to split often using the same pattern. BTW the output is:

[1, 1, Abdul-Jabbar, Karim, 1996, 1974]
[1, 1, Abdul-Jabbar, Karim, 1996, 1974]
[1, 1, Abdul-Jabbar, Karim, 1996, 1974]

回答2:

Use the Pattern#quote() method for escaping ||. Try:

final String[] tokens = myString.split(Pattern.quote("||"));

This is required because | is an alternation character and hence gains a special meaning when passed to split call (basically the argument to split is a regular expression in string form).

回答3:

Double quotes are interpreted as literals in regex; they are not special characters. You are trying to match a literal "||".

Just use Pattern.quote(delimiter):

As requested, here's a line of code (same as Sanjay's)

final String[] tokens = line.split(Pattern.quote(delimiter));

If that doesn't work, you're not passing in the correct delimiter.

回答4:

String[] strArray= str.split(Pattern.quote("||"));

where

str = "1||1||Abdul-Jabbar||Karim||1996||1974";
Pattern.quote("||") will ignore the special character.
.split function will split the string for every occurrence of ||.
strArray will have the array of string that is delimited by ||.

回答5:

Pipe (|) is a special character in regex. to escape it, you need to prefix it with backslash (\). But in java, backslash is also an escape character. so again you need to escape it with another backslash. So your regex should be \\|\\| e.g, String[] tokens = myString.split("\\|\\|");

回答6:

Split uses regex, and the pipe char | has special meaning in regex, so you need to escape it. There are a few ways to do this, but here's the simplest:

String[] tokens = line.split("\\|\\|");

回答7:

There is something wrong in your setDelimiter() function. You don't want to double quote the delimiters, do you?

public void setDelimiter(String delimiter) {
    char[] c = delimiter.toCharArray();
    this.delimiter = "\\" + c[0] + "\\" + c[1];
    System.out.println("Delimiter string is: " + this.delimiter);
}

However, as other users have said, it's better to use the Pattern.quote() method to escape your delimiter if your requirements permit.

回答8:

The problem is because you are adding quotes to your delimiter. It should be removed, and it will work fine.

public void setDelimiter(String delimiter) {
    char[] c = delimiter.toCharArray();
    this.delimiter = "\\" + c[0] + "\\" + c[1];
    System.out.println("Delimiter string is: " + this.delimiter);
}

回答9:

String[] splitArray = subjectString.split("\\|\\|");

You use a function:

public String[] stringSplit(String string){

    String[] splitArray = string.split("\\|\\|");
    return splitArray;
}

回答10:

StringTokenizer st = new StringTokenizer("1||1||Abdul-Jabbar||Karim||1996||1974",
             "||");
while(st.hasMoreTokens()){
     System.out.println(st.nextElement());
}

Answer will print

1 1 Abdul-Jabbar Karim 1996 1974

来源：https://stackoverflow.com/questions/7021074/string-delimiter-in-string-split-method

标签

java

string

split

delimiter