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java - 使用换行符将字符串中的行限制为 60 个字符

问题描述

该程序用于从字符串中删除双倍、三倍……空格，并将字符限制为每行 60 个。

问题是当想法是它必须跳过它们时，它会将单词放入第 60 位的行中。

输出是：

Java was originally developed by James Gosling at Sun Microsystems
(which has since been acquired by Oracle) and released in 1995
as a core component of Sun Microsystems' Java platform.

但正确的输出必须是：

Java was originally developed by James Gosling at Sun
Microsystems (which has since been acquired by Oracle) and
released in 1995 as a core component of Sun Microsystems'
Java platform.

到目前为止我的代码：


      StringBuilder sb = new StringBuilder(text.replaceAll("(^ )|( $)", "").replaceAll("\\s{2,}", " "));
       int i = 0;
       while ((i = sb.indexOf(" ", i + 60)) != -1) {
           sb.replace(i,i+1,"\n");
       }
       String result = sb.toString();
       return result;
   }

标签： javastringreplacenewlinestringbuilder

解决方案

这是我第 24 次试运行的结果。

Java was originally developed by James Gosling at Sun Microsystems
(which has since been acquired by Oracle) and released in 1995
as a core component of Sun Microsystems'   Java platform.

Java was originally developed by James Gosling at Sun
Microsystems (which has since been acquired by Oracle) and
released in 1995 as a core component of Sun Microsystems'
Java platform.

第一段是输入。第二段是输出。

看一下代码。你看到几个被注释掉的System.out.println语句吗？这就是您发现代码问题的方式。您编写几行代码，然后打印中间结果。冲洗并重复，直到您的代码有效。

这是完整的可运行代码。

public class FixedLengthLines {

    public static void main(String[] args) {
        new FixedLengthLines().processString();
    }
    
    public void processString() {
        String text = "Java was originally developed by James Gosling at Sun Microsystems\r\n" + 
                "(which has since been acquired by Oracle) and released in 1995\r\n" + 
                "as a core component of Sun Microsystems'   Java platform.";
        String temp = text.replaceAll("\\s{2,}", " ");
//      System.out.println(temp);
        
        int lineLength = 60;
        int lineIndex = 0;
        int endIndex = Math.min(lineIndex + lineLength, temp.length());
        StringBuilder builder = new StringBuilder();
        
        while (lineIndex < endIndex) {
//          System.out.println(lineIndex + " " + endIndex + " " + temp.length());
            
            if (endIndex >= lineIndex + lineLength) {
                endIndex = temp.lastIndexOf(" ", endIndex); 
            }
            
            builder.append(temp.substring(lineIndex, endIndex));
            builder.append(System.lineSeparator());
            
//          System.out.println(endIndex + " " + temp.substring(lineIndex, endIndex));
            
            lineIndex = endIndex + 1;
            endIndex = Math.min(lineIndex + lineLength, temp.length());
        }
        
        System.out.println(text);
        System.out.println();
        System.out.println(builder.toString());
    }

}

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