Java Scanner to split records by an empty line

Question

I have records formatted the following way:

record 1 line
record 1 line
record 1 line

record 2 line
record 2 line
record 2 line

...

I'd like to use a java Scanner to pull each record's lines out. However, my patter does not seem to be working correctly.

new Scanner(reader).useDelimiter(Pattern.compile("^\\s*$"));

I get back my input rather then scanner.next() giving me the lines for each record.

Answer 1

The solution I came up with was this:
new Scanner(reader).useDelimiter(Pattern.compile("^\\\\s*$", Pattern.MULTILINE));

This will return the record lines as a group:
scanner.next()
yields:
record 1 line 1
record 1 line 2
record 1 line 3
doing it again scanner.next()
yields:
record 2 line 1
record 2 line 2
record 2 line 3
If you desire just the lines individually, use @bart 's solution.

Answer 2

我想要多行尝试

"\\n\\n+"

Answer 3

This is a bit of guess, but do you really need to use regex here? I think you just need to set the delimiter as a new line char.

Answer 4

I would do it like this.

StringBuilder sb = new StringBuilder();
ArrayList<String> records = new ArrayList<String>();
while(scanner.hasNextLine()){
    String line = scanner.nextLine();
    if("".equals(line.trim())){
        records.add(sb.toString());
        sb = new StringBuilder();
    }else{
        sb.append(line);
        sb.append("\n");
    }
}
System.out.println(records);

I didn't test this so it might have some silly errors.