Java8 新API讀取檔案内容

使用Java8 提供的新API讀取檔案内容，代碼簡潔、友善。

1、測試代碼

import java.io.IOException;
import java.nio.charset.Charset;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.Stream;

/**
 * Java8 新API讀取檔案内容
 *
 * Created by wangyingjie1 on 2017/2/22.
 */
public class ReadFile {

    public static void main(String[] args) {

        try {

            String fileName = "D:\\SrcCode\\Java8InAction\\src\\main\\resources\\lambdasinaction\\chap5\\data.txt";

            //讀取檔案
            Stream<String> stringStream = Files
                    .lines(Paths.get(fileName), Charset.defaultCharset())
                    .flatMap(line -> Arrays.stream(line.split(" ")));

            List<String> words = stringStream.collect(Collectors.toList());
            System.out.println("words===>" + words);


            List<String> lineLists = Files
                    .lines(Paths.get(fileName), Charset.defaultCharset())
                    .flatMap(line -> Arrays.stream(line.split("\n")))
                    .collect(Collectors.toList());

            //輸出檔案函數
            System.out.println("lineLists====" + lineLists.size());

            //輸出每一行檔案内容
            lineLists.stream().forEach(System.out::println);

            //統計單詞的個數
            long uniqueWords = Files.lines(Paths.get(fileName), Charset.defaultCharset())
                    .flatMap(line -> Arrays.stream(line.split(" ")))
                    .distinct()
                    .count();

            System.out.println("There are " + uniqueWords + " unique words in data.txt");

        } catch (IOException e) {
            e.printStackTrace();
        }
    }


}
           

2、檔案data.txt

The quick brown fox jumped over the lazy dog

The lazy dog jumped over the quick brown fox