要做到这一点，

例如:

如果在当前目录中有dataFile.txt

import java.io.*;
import java.util.Scanner;
import java.io.FileNotFoundException;

public class readByLine
{
    public readByLine() throws FileNotFoundException
    {
        Scanner linReader = new Scanner(new File("dataFile.txt"));

        while (linReader.hasNext())
        {
            String line = linReader.nextLine();
            System.out.println(line);
        }
        linReader.close();

    }

    public static void main(String args[])  throws FileNotFoundException
    {
        new readByLine();
    }
}

输出如下:

在Java 7中:

String folderPath = "C:/folderOfMyFile";
Path path = Paths.get(folderPath, "myFileName.csv"); //or any text file eg.: txt, bat, etc
Charset charset = Charset.forName("UTF-8");

try (BufferedReader reader = Files.newBufferedReader(path , charset)) {
  while ((line = reader.readLine()) != null ) {
    //separate all csv fields into string array
    String[] lineVariables = line.split(","); 
  }
} catch (IOException e) {
    System.err.println(e);
}

一旦Java 8发布(2014年3月)，你就可以使用流了:

try (Stream<String> lines = Files.lines(Paths.get(filename), Charset.defaultCharset())) {
  lines.forEachOrdered(line -> process(line));
}

打印文件中的所有行:

try (Stream<String> lines = Files.lines(file, Charset.defaultCharset())) {
  lines.forEachOrdered(System.out::println);
}

要做到这一点，

例如:

如果在当前目录中有dataFile.txt

import java.io.*;
import java.util.Scanner;
import java.io.FileNotFoundException;

public class readByLine
{
    public readByLine() throws FileNotFoundException
    {
        Scanner linReader = new Scanner(new File("dataFile.txt"));

        while (linReader.hasNext())
        {
            String line = linReader.nextLine();
            System.out.println(line);
        }
        linReader.close();

    }

    public static void main(String args[])  throws FileNotFoundException
    {
        new readByLine();
    }
}

输出如下:

Java 9:

try (Stream<String> stream = Files.lines(Paths.get(fileName))) {
    stream.forEach(System.out::println);
}

在Java 8中，除了使用Files.lines()，还有另一种方法。如果您的输入源不是文件，而是更抽象的东西，如Reader或InputStream，则可以通过BufferedReaders lines()方法对行进行流处理。

例如:

try (BufferedReader reader = new BufferedReader(...)) {
  reader.lines().forEach(line -> processLine(line));
}

BufferedReader读取的每个输入行都会调用processLine()。