如何从java中的字符串中读取第二行

Question

I have a string with multiple lines and I want to read a specific line and save it to an other string. That's my code

String text ="example text line\n
example text line\n
example text line\n
example text line\n
example text line\n
example text line\n
example text line\n";

String textline1="";
String textline2="";

on the above strings textline1 and textline2 I want to save the specific line.

Answer 1

You can split on the new-line character:

//To split on the new line

String[] lines = s.split("\\n");

//To read 1st line

String line1 = lines[0];
System.out.println(line1);

//To read 2nd line

String line2 = lines[1];
System.out.println(line2);

Answer 2

Using java.io.LineNumberReader may also be useful here, as it handles the various types of line endings that may be encountered. From its API doc :

A line is considered to be terminated by any one of a line feed ('\\n'), a carriage return ('\\r'), or a carriage return followed immediately by a linefeed.

Example code:

package com.dovetail.routing.components.camel.beans;

import static org.assertj.core.api.Assertions.assertThat;

import java.io.IOException;
import java.io.LineNumberReader;
import java.io.StringReader;

import org.testng.annotations.Test;

@Test
public final class SoTest {

    private String text = "example text line 1\nexample text line 2\nexample text line\nexample text line\nexample text line\nexample text line\nexample text line\n";

    String textline1 = "";
    String textline2 = "";

    public void testLineExtract() throws IOException {
        LineNumberReader reader = new LineNumberReader(new StringReader(text));
        String currentLine = null;
        String textLine1 = null;
        String textLine2 = null;
        while ((currentLine = reader.readLine()) != null) {
            if (reader.getLineNumber() == 1) {
                textLine1 = currentLine;
            }
            if (reader.getLineNumber() == 2) {
                textLine2 = currentLine;
            }
        }
        assertThat(textLine1).isEqualTo("example text line 1");
        assertThat(textLine2).isEqualTo("example text line 2");
    }

}

Answer 3

I would use Guava 's Splitter to turn text into an Iterable<String> (call it, say, lines ). Then it's just a matter of getting your element via Iterables.get(lines, 1) ;