大字符串在java中分割成具有最大长度的行

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/ 

我想将这个大字符串拆分成行，并且每行中的行不应超过MAX_LINE_LENGTH个字符。

到目前为止我尝试了什么

 int MAX_LINE_LENGTH = 20; System.out.print(Arrays.toString(input.split("(?<=\\G.{MAX_LINE_LENGTH})"))); //maximum length of line 20 characters 

输出：

 [THESE TERMS AND COND, ITIONS OF SERVICE (t, he Terms) ARE A LEGA, L AND B ... 

它导致文字破裂 。 我不想要这个。 而不是我想得到这样的输出：

 [THESE TERMS AND , CONDITIONS OF , SERVICE (the Terms) , ARE A LEGAL AND B ... 

还添加了一个条件：如果字长大于MAX_LINE_LENGTH，那么该单词应该被拆分。

解决方案应该没有外部jar子的帮助。

Answer 1

只需逐字逐句地遍历字符串，并在单词超过限制时中断。

 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(); } 

我只是徒手打字，你可能需要推动并刺激一下才能编译。

错误：如果输入中的单词长于maxLineLength ，它将被附加到当前行而不是它自己的太长行。 我假设您的行长度大约为80或120个字符，在这种情况下，这不太可能是一个问题。

Answer 2

最佳：使用Apache Commons Lang：

org.apache.commons.lang.WordUtils

 /** * 
Wraps a single line of text, identifying words by ' '.
 * * 
New lines will be separated by the system property line separator. * Very long words, such as URLs will not be wrapped.
 * * 
Leading spaces on a new line are stripped. * Trailing spaces are not stripped.
 * * 
 * WordUtils.wrap(null, *) = null * WordUtils.wrap("", *) = "" * 
 * * @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, null if null input */ public static String wrap(String str, int wrapLength) { return wrap(str, wrapLength, null, false); } 

Answer 3

感谢Barend Garvelink的回答。 我修改了上面的代码来修复Bug：“如果输入中的单词长于maxCharInLine”

 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"); } 

Answer 4

您可以使用Apache Commans Lang的WordUtils.wrap方法

  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)); }} 

产量

  [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.] 

Answer 5

从@Barend的建议开始，以下是我的最终版本，稍作修改：

 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)); 

产出：

 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. 

Answer 6

我最近编写了一些方法来执行此操作，如果其中一行中没有空格字符，则在使用中间字分割之前选择拆分其他非字母数字字符。

以下是我的结果：

（使用我在这里发布的lastIndexOfRegex()方法。）

 /** * 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 * maxLength 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(); } 

Answer 7

我的版本（之前没有用）

 public static List breakSentenceSmart(String text, int maxWidth) { StringTokenizer stringTokenizer = new StringTokenizer(text, " "); List lines = new ArrayList(); 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; } 

Answer 8

从Java 8开始，您还可以使用Streams来解决此类问题。

下面你可以找到一个使用.collect（）方法利用Reduction的完整示例

我认为这个应该比其他非第三方解决方案更短。

 private static String multiLine(String longString, String splitter, int maxLength) { return Arrays.stream(longString.split(splitter)) .collect( ArrayList::new, (l, s) -> { Function, 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)); }