Java –如何将文件读入列表？-蒲公英云

Java –如何将文件读入列表？

在Java中，几乎没有办法将文件逐行读取到List

Java 8流

List result;

 try (Stream<String> lines = Files.lines(Paths.get(fileName))) {
     result = lines.collect(Collectors.toList());
 }

Java 7

Files.readAllLines(new File(fileName).toPath(), Charset.defaultCharset());

3.经典的BufferedReader示例。

List<String> result = new ArrayList<>();
    BufferedReader br = null;
    try {
        br = new BufferedReader(new FileReader(fileName));
        String line;
        while ((line = br.readLine()) != null) {
            result.add(line);
        }
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        if (br != null) {
            br.close();
        }
    }

1.文件->列表

1.1虚拟文件

d:\\server.log

a
b
c
d
1
2
3

1.2将文件读入List

JavaExample.java

package com.mkyong.example;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.nio.charset.Charset;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.Stream;
public class JavaExample {
    public static void main(String[] args) {
        String filename = "d:\\server.log";
        try {
            List list = readByJavaClassic(filename);
            list.forEach(System.out::println);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    private static List readByJava8(String fileName) throws IOException {
        List<String> result;
        try (Stream<String> lines = Files.lines(Paths.get(fileName))) {
            result = lines.collect(Collectors.toList());
        }
        return result;
    }
    private static List readByJava7(String fileName) throws IOException {
        return Files.readAllLines(new File(fileName).toPath(), Charset.defaultCharset());
    }
    private static List readByJavaClassic(String fileName) throws IOException {
        List<String> result = new ArrayList<>();
        BufferedReader br = null;
        try {
            br = new BufferedReader(new FileReader(fileName));
            String line;
            while ((line = br.readLine()) != null) {
                result.add(line);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (br != null) {
                br.close();
            }
        }
        return result;
    }
}