javaで最大長の行に分割された大きな文字列
String input = "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.";
//text copied from http://www.nationalgeographic.com/community/terms/
この大きな文字列を行に分割したいのですが、各行のMAX_LINE_LENGTH文字を超えてはいけません。
これまでに試したこと
int MAX_LINE_LENGTH = 20;
System.out.print(Arrays.toString(input.split("(?<=\\G.{MAX_LINE_LENGTH})")));
//maximum length of line 20 characters
出力：
[THESE TERMS AND COND, ITIONS OF SERVICE (t, he Terms) ARE A LEGA, L AND B ...
単語の分割を引き起こします。これは欲しくない。代わりに、次のような出力を取得したいと思います。
[THESE TERMS AND , CONDITIONS OF , SERVICE (the Terms) , ARE A LEGAL AND B ...
もう1つの条件が追加されました：ワードの長さがMAX_LINE_LENGTHより大きい場合、ワードは分割されます。
そして、解決策は外部のjarファイルの助けなしにすべきです。
文字列をWordごとに反復し、Wordが制限を超えるたびに中断します。
public String addLinebreaks(String input, int maxLineLength) {
StringTokenizer tok = new StringTokenizer(input, " ");
StringBuilder output = new StringBuilder(input.length());
int lineLen = 0;
while (tok.hasMoreTokens()) {
String Word = tok.nextToken();
if (lineLen + Word.length() > maxLineLength) {
output.append("\n");
lineLen = 0;
}
output.append(Word);
lineLen += Word.length();
}
return output.toString();
}
私はそれをフリーハンドで入力しただけで、それをコンパイルさせるために少しプッシュしてプロダクションする必要があるかもしれません。
バグ：入力内の単語がmaxLineLengthよりも長い場合、その単語が長すぎる行ではなく、現在の行に追加されます。私はあなたの行の長さが80または120文字のようなものだと思います、その場合これは問題になる可能性は低いです。
ベスト：Apache Commons Langを使用：
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);
}
Apache Commons LangのWordUtils.wrapメソッドを使用できます
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));
}}
出力
[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.]
あなたの答えを提供してくれたBarend Garvelinkに感謝します。上記のコードを修正してバグを修正しました：「入力内のワードがmaxCharInLineよりも長い場合」
public String[] splitIntoLine(String input, int maxCharInLine){
StringTokenizer tok = new StringTokenizer(input, " ");
StringBuilder output = new StringBuilder(input.length());
int lineLen = 0;
while (tok.hasMoreTokens()) {
String Word = tok.nextToken();
while(Word.length() > maxCharInLine){
output.append(Word.substring(0, maxCharInLine-lineLen) + "\n");
Word = Word.substring(maxCharInLine-lineLen);
lineLen = 0;
}
if (lineLen + Word.length() > maxCharInLine) {
output.append("\n");
lineLen = 0;
}
output.append(Word + " ");
lineLen += Word.length() + 1;
}
// output.split();
// return output.toString();
return output.toString().split("\n");
}
@Barendの提案から始めて、以下はマイナーな変更を加えた私の最終バージョンです：
private static final char NEWLINE = '\n';
private static final String SPACE_SEPARATOR = " ";
//if text has \n, \r or \t symbols it's better to split by \s+
private static final String SPLIT_REGEXP= "\\s+";
public static String breakLines(String input, int maxLineLength) {
String[] tokens = input.split(SPLIT_REGEXP);
StringBuilder output = new StringBuilder(input.length());
int lineLen = 0;
for (int i = 0; i < tokens.length; i++) {
String Word = tokens[i];
if (lineLen + (SPACE_SEPARATOR + Word).length() > maxLineLength) {
if (i > 0) {
output.append(NEWLINE);
}
lineLen = 0;
}
if (i < tokens.length - 1 && (lineLen + (Word + SPACE_SEPARATOR).length() + tokens[i + 1].length() <=
maxLineLength)) {
Word += SPACE_SEPARATOR;
}
output.append(Word);
lineLen += Word.length();
}
return output.toString();
}
System.out.println(breakLines("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.", 20));
出力：
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.
私は最近、これを行うためのいくつかの方法を記述しました。行の1つに空白文字が存在しない場合、中単語の分割に頼る前に、他の非英数字に分割することを選択します。
これが私にとってどのように判明したかです：
（私が投稿したlastIndexOfRegex()メソッドを使用 here ）
/**
* 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();
}
私のバージョン（以前は動作していませんでした）
public static List<String> breakSentenceSmart(String text, int maxWidth) {
StringTokenizer stringTokenizer = new StringTokenizer(text, " ");
List<String> lines = new ArrayList<String>();
StringBuilder currLine = new StringBuilder();
while (stringTokenizer.hasMoreTokens()) {
String Word = stringTokenizer.nextToken();
boolean wordPut=false;
while (!wordPut) {
if(currLine.length()+Word.length()==maxWidth) { //exactly fits -> dont add the space
currLine.append(Word);
wordPut=true;
}
else if(currLine.length()+Word.length()<=maxWidth) { //whole Word can be put
if(stringTokenizer.hasMoreTokens()) {
currLine.append(Word + " ");
}else{
currLine.append(Word);
}
wordPut=true;
}else{
if(Word.length()>maxWidth) {
int lineLengthLeft = maxWidth - currLine.length();
String firstWordPart = Word.substring(0, lineLengthLeft);
currLine.append(firstWordPart);
//lines.add(currLine.toString());
Word = Word.substring(lineLengthLeft);
//currLine = new StringBuilder();
}
lines.add(currLine.toString());
currLine = new StringBuilder();
}
}
//
}
if(currLine.length()>0) { //add whats left
lines.add(currLine.toString());
}
return lines;
}
Java 8なので、Streamsを使用してそのような問題に取り組むこともできます。
以下に、 。collect（）メソッドを使用した削減 を使用する完全な例を示します。
これは他のサードパーティ以外のソリューションよりも短いはずです。
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));
}