Java字符串：用于将长字符串拆分为固定长度的较小部分并将其组合的递归解决方案

Question

According to UI component requirement, with the use of long String value I have to populate fixed length smaller String values and combine them.

Ex:-  long String value: AAABBBCCDEEEFFGGGG

      Fixed length smaller String value: AAA
                                         BBB
                                         CCD
                                         EEE
                                         FFG
                                         GGG

For make this enable I have write some utility method as follow. I want to know, as a optimise solution whether it can write some recursion method ? Thanks.

/**
 * @param fullLongString Long String value
 * @param maxLengthOfPart Maximum length of the smaller String 
 * @return String result as a short String
 */
public static String getShortString(String fullLongString, int maxLengthOfPart) {

    if((fullLongString == null) || (fullLongString.trim().equals("")) || (maxLengthOfPart <= 0) || (fullLongString.length() <= maxLengthOfPart)) {
        return fullLongString;
    }

    StringBuilder fullShortString = new StringBuilder();
    int numberOfStringParts = fullLongString.length() / maxLengthOfPart;

    int startIndex = 0;
    int endIndex = maxLengthOfPart;

    for(int i = 0; i < numberOfStringParts; i++) {

        String smallPart = fullLongString.substring(startIndex, endIndex);

        if(i == 0) {
            fullShortString.append(smallPart);
        } else {
            fullShortString.append("\n").append(smallPart);
        }

        startIndex = endIndex;
        endIndex += maxLengthOfPart;
    }

    String remainPart = fullLongString.substring((endIndex - maxLengthOfPart), (fullLongString.length()));

    if((remainPart != null) && (!remainPart.trim().equals(""))) {
        fullShortString.append("\n").append(remainPart);
    }

    return fullShortString.toString();
}

Answer 1

This worked for me. Recursion saves a lot of code.

/**
 * @param fullLongString Long String value
 * @param maxLengthOfPart Maximum length of the smaller String 
 * @return String result as a short String
 */
public static String getShortString(String fullLongString, int maxLengthOfPart) {

    if((fullLongString == null) || (fullLongString.trim().equals("")) || (maxLengthOfPart <= 0) || (fullLongString.length() <= maxLengthOfPart)) {
        return fullLongString;
    } else {
       String firstPart = fullLongString.substring(0, maxLengthOfPart);
       return firstPart + "\n" + getShortString(fullLongString.substring(maxLengthOfPart, fullLongString.length()),maxLengthOfPart);
    }

}

Answer 2

I recommend the Guava library which comes with a Splitter and a Joiner class.

Usage :

public static String splitEqual(String strand, int width) {
    return Joiner.on('\n').join(Splitter.fixedLength(width).trimResults().split(strand));
}