Java：处理要从文件读取的流

Question

for a lab at my University I'm developing a system in Java that is able to store data from a file (given the file path as a String). I was trying to handle the problem using a stream of lines from the path, but I got stuck at an early stage. The file is organised as follow: the different fields of a line are separated by ";" and each line starts with a "P" or a "D". Depending on this parameter, I'll use the contenent of the line to create a "Patient" object or a "Doctor" object, subsequently stored in two different maps (patients or doctors). I did the following:

Path p= Paths.get(path);
Stream <String> lines=Files.lines(p, StandardCharsets.UTF_8);
lines.flatMap(l->Stream.of(l.split("; ")))....

My idea was to check the word at the beginning of the line and, according to that, the remaining element would be used as parameter for a method able to create and store the corresponding object(insertPatient or insertDoctor). But I haven't got the faintest idea of how to do that. I know different way to do the same, but I really want to develop the solution using a stream, at least in the procedure of reading the different lines. Thanks, Gianluca.

Answer 1

try (Stream<> lines = Files.lines(p, StandardCharsets.UTF_8)) { // 1
    lines.map(line -> line.split(";"))                          // 2
         .forEach(lineAsArray -> {
             if (lineAsArray[0].equals("D")) {
                 insertDoctor(lineAsArray);
             }
             else if (lineAsArray[0].equals("P")) {
                 insertPatient(lineAsArray);
             }
         });
}

1. Use try-with-resources to make sure the stream, and thus the file reader, is closed
2. Don't use flatMap, since you want to act on complete lines, and not on cells.