Chaîne de taille divisé en lignes avec un maximum de longueur en java

Mieux : l'utilisation d'Apache Commons Lang :

org.apache.commons.lang.WordUtils

/**
 * <p>Wraps a single line of text, identifying words by <code>' '</code>.</p>
 * 
 * <p>New lines will be separated by the system property line separator.
 * Very long words, such as URLs will <i>not</i> be wrapped.</p>
 * 
 * <p>Leading spaces on a new line are stripped.
 * Trailing spaces are not stripped.</p>
 *
 * <pre>
 * WordUtils.wrap(null, *) = null
 * WordUtils.wrap("", *) = ""
 * </pre>
 *
 * @param str  the String to be word wrapped, may be null
 * @param wrapLength  the column to wrap the words at, less than 1 is treated as 1
 * @return a line with newlines inserted, <code>null</code> if null input
 */
public static String wrap(String str, int wrapLength) {
    return wrap(str, wrapLength, null, false);
}

Vous pouvez utiliser WordUtils.méthode d'enveloppement de Apache Commans Lang

 import java.util.*;
 import org.apache.commons.lang3.text.WordUtils;
 public class test3 {


public static void main(String[] args) {

    String S = "THESE TERMS AND CONDITIONS OF SERVICE (the Terms) ARE A LEGAL AND BINDING AGREEMENT BETWEEN YOU AND NATIONAL GEOGRAPHIC governing your use of this site, www.nationalgeographic.com, which includes but is not limited to products, software and services offered by way of the website such as the Video Player, Uploader, and other applications that link to these Terms (the Site). Please review the Terms fully before you continue to use the Site. By using the Site, you agree to be bound by the Terms. You shall also be subject to any additional terms posted with respect to individual sections of the Site. Please review our Privacy Policy, which also governs your use of the Site, to understand our practices. If you do not agree, please discontinue using the Site. National Geographic reserves the right to change the Terms at any time without prior notice. Your continued access or use of the Site after such changes indicates your acceptance of the Terms as modified. It is your responsibility to review the Terms regularly. The Terms were last updated on 18 July 2011.";
    String F = WordUtils.wrap(S, 20);
    String[] F1 =  F.split(System.lineSeparator());
    System.out.println(Arrays.toString(F1));

}}

Sortie

   [THESE TERMS AND, CONDITIONS OF, SERVICE (the Terms), ARE A LEGAL AND, BINDING AGREEMENT, BETWEEN YOU AND, NATIONAL GEOGRAPHIC, governing your use, of this site,, www.nationalgeographic.com,, which includes but, is not limited to, products, software, and services offered, by way of the, website such as the, Video Player,, Uploader, and other, applications that, link to these Terms, (the Site). Please, review the Terms, fully before you, continue to use the, Site. By using the, Site, you agree to, be bound by the, Terms. You shall, also be subject to, any additional terms, posted with respect, to individual, sections of the, Site. Please review, our Privacy Policy,, which also governs, your use of the, Site, to understand, our practices. If, you do not agree,, please discontinue, using the Site., National Geographic, reserves the right, to change the Terms, at any time without, prior notice. Your, continued access or, use of the Site, after such changes, indicates your, acceptance of the, Terms as modified., It is your, responsibility to, review the Terms, regularly. The Terms, were last updated on, 18 July 2011.]

J'ai récemment écrit un peu de méthodes pour ce faire que, si aucune espaces sont présents dans l'une des lignes, opte pour la séparation d'autres caractères non alphanumériques avant de recourir à une évaluation à mi-mot split.

Ici est de savoir comment il s'est avéré pour moi:

(Utilise le lastIndexOfRegex() méthodes que j'ai posté ici.)

/**
* Indicates that a String search operation yielded no results.
*/
public static final int NOT_FOUND = -1;
/**
* Version of lastIndexOf that uses regular expressions for searching.
* By Tomer Godinger.
* 
* @param str String in which to search for the pattern.
* @param toFind Pattern to locate.
* @return The index of the requested pattern, if found; NOT_FOUND (-1) otherwise.
*/
public static int lastIndexOfRegex(String str, String toFind)
{
Pattern pattern = Pattern.compile(toFind);
Matcher matcher = pattern.matcher(str);
//Default to the NOT_FOUND constant
int lastIndex = NOT_FOUND;
//Search for the given pattern
while (matcher.find())
{
lastIndex = matcher.start();
}
return lastIndex;
}
/**
* Finds the last index of the given regular expression pattern in the given string,
* starting from the given index (and conceptually going backwards).
* By Tomer Godinger.
* 
* @param str String in which to search for the pattern.
* @param toFind Pattern to locate.
* @param fromIndex Maximum allowed index.
* @return The index of the requested pattern, if found; NOT_FOUND (-1) otherwise.
*/
public static int lastIndexOfRegex(String str, String toFind, int fromIndex)
{
//Limit the search by searching on a suitable substring
return lastIndexOfRegex(str.substring(0, fromIndex), toFind);
}
/**
* Breaks the given string into lines as best possible, each of which no longer than
* <code>maxLength</code> characters.
* By Tomer Godinger.
* 
* @param str The string to break into lines.
* @param maxLength Maximum length of each line.
* @param newLineString The string to use for line breaking.
* @return The resulting multi-line string.
*/
public static String breakStringToLines(String str, int maxLength, String newLineString)
{
StringBuilder result = new StringBuilder();
while (str.length() > maxLength)
{
//Attempt to break on whitespace first,
int breakingIndex = lastIndexOfRegex(str, "\\s", maxLength);
//Then on other non-alphanumeric characters,
if (breakingIndex == NOT_FOUND) breakingIndex = lastIndexOfRegex(str, "[^a-zA-Z0-9]", maxLength);
//And if all else fails, break in the middle of the word
if (breakingIndex == NOT_FOUND) breakingIndex = maxLength;
//Append each prepared line to the builder
result.append(str.substring(0, breakingIndex + 1));
result.append(newLineString);
//And start the next line
str = str.substring(breakingIndex + 1);
}
//Check if there are any residual characters left
if (str.length() > 0)
{
result.append(str);
}
//Return the resulting string
return result.toString();
}

Depuis Java 8 vous pouvez également utiliser Flux pour s'attaquer à ces problèmes.

Suivant vous pouvez trouver un exemple complet qui utilise Réduction à l'aide de l' .collect() méthode

Je pense que celui-ci devrait être plus courte que les autres non-3e partie des solutions.

private static String multiLine(String longString, String splitter, int maxLength) {
return Arrays.stream(longString.split(splitter))
.collect(
ArrayList<String>::new,     
(l, s) -> {
Function<ArrayList<String>, Integer> id = list -> list.size() - 1;
if(l.size() == 0 || (l.get(id.apply(l)).length() != 0 && l.get(id.apply(l)).length() + s.length() >= maxLength)) l.add("");
l.set(id.apply(l), l.get(id.apply(l)) + (l.get(id.apply(l)).length() == 0 ? "" : splitter) + s);
},
(l1, l2) -> l1.addAll(l2))
.stream().reduce((s1, s2) -> s1 + "\n" + s2).get();
}
public static void main(String[] args) {
String longString = "THESE TERMS AND CONDITIONS OF SERVICE (the Terms) ARE A LEGAL AND BINDING AGREEMENT BETWEEN YOU AND NATIONAL GEOGRAPHIC governing your use of this site, www.nationalgeographic.com, which includes but is not limited to products, software and services offered by way of the website such as the Video Player, Uploader, and other applications that link to these Terms (the Site). Please review the Terms fully before you continue to use the Site. By using the Site, you agree to be bound by the Terms. You shall also be subject to any additional terms posted with respect to individual sections of the Site. Please review our Privacy Policy, which also governs your use of the Site, to understand our practices. If you do not agree, please discontinue using the Site. National Geographic reserves the right to change the Terms at any time without prior notice. Your continued access or use of the Site after such changes indicates your acceptance of the Terms as modified. It is your responsibility to review the Terms regularly. The Terms were last updated on 18 July 2011.";
String SPLITTER = " ";
int MAX_LENGTH = 20;
System.out.println(multiLine(longString, SPLITTER, MAX_LENGTH));
}