Java等价于Perl函数，仅打印唯一行？

Question

Trying to find a java equivalent of this line of Perl code:

perl -ne 'print unless $a{$_}++'

Did some looking around but to no avail! Cheers, Ger

Answer 1

As it's trivia-like question, not a real production problem, then I suppose that Java 8 is allowed.

import java.io.BufferedReader;
import java.io.InputStreamReader;

public class PrintUnique {
    public static void main(String[] args) {
        new BufferedReader(new InputStreamReader(System.in)).lines().distinct()
            .forEach(System.out::println);
    }
}

Java 6 solution would be like this:

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.HashSet;
import java.util.Set;

public class PrintUnique {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        Set<String> lines = new HashSet<String>();
        String line;
        while((line = br.readLine()) != null) {
            if(lines.add(line))
                System.out.println(line);
        }
    }
}