Parse and read data from a text file [duplicate]

问题

I have data in my text file in the following format

apple fruit
carrot vegetable
potato vegetable

I want to read this line by line and split at the first space and store it in a set or map or any similar collections of java. (key and value pairs)

example :-
"apple fruit" should be stored in a map where the key = apple and value = fruit.

回答1:

The Scanner class is probably what you're after.

As an example:

 Scanner sc = new Scanner(new File("your_input.txt"));
 while (sc.hasNextLine()) {
     String line = sc.nextLine();
     // do whatever you need with current line
 }
 sc.close();

回答2:

You can do something like this:

BufferedReader br = new BufferedReader(new FileReader("file.txt"));
String currentLine;
while ((currentLine = br.readLine()) != null) {
  String[] strArgs = currentLine.split(" "); 
  //Use HashMap to enter key Value pair.
  //You may to use fruit vegetable as key rather than other way around
}

回答3:

Since java 8 you can just do

Set<String[]> collect = Files.lines(Paths.get("/Users/me/file.txt"))
            .map(line -> line.split(" ", 2))
            .collect(Collectors.toSet());

if you want a map, you can just replace the Collectors.toSet by Collectors.toMap()

Map<String, String> result = Files.lines(Paths.get("/Users/me/file.txt"))
            .map(line -> line.split(" ", 2))
            .map(Arrays::asList)
            .collect(Collectors.toMap(list -> list.get(0), list -> list.get(1)));

来源：https://stackoverflow.com/questions/42258936/parse-and-read-data-from-a-text-file

标签

java

parsing

set

filereader