void方法不会操纵字符串

Question

我有一个void方法,它应该采用一个String并根据分隔符将其拆分为两个字符串.使用调试器后,该方法似乎正常工作,但我传入的两个空字符串,用于存储结果的方法似乎没有得到更新.我必须在这里做一些愚蠢的事,但任何帮助都表示赞赏!

public static void main(String[] args) {
    String dictFile = "/Users/simonrhillary/Desktop/Dictionary(3).txt";
    String synFile = "/Users/simonrhillary/Desktop/Synonyms(2).txt";
    fileReader dictFR = new fileReader();
    fileReader synFR = new fileReader();
    dictFR.filePath = dictFile;
    synFR.filePath = synFile;
    dictFR.openFile(dictFile);
    synFR.openFile(synFile);
    String[] dictionary = dictFR.fileToArray();
    String[] synonyms = synFR.fileToArray();
    String regx = "^[aflmptu]+$";
    String regexTemplate = "^[]+$";
    String word1 = "";
    String word2 = "";
    synToWords(synFR.getLine(3), word1, word2);//error seems to be here. 
                                                       //word1 and word 2 stay ""
    System.out.println(word1 +" " + word2);
    printArray(findCombos(dictionary, word1, word2));

}

public static void synToWords(String syn, String wordI, String wordII){
    String[] words = syn.split("\\t");
    wordI = wordI + words[0];
    wordII = wordII + words[1];
}

我还没有发布其他方法,但它们都运行良好.这只是解决问题的synToWords方法.非常感谢!

Answer 1

Java 按值传递引用.所以这一行:

wordI = wordI + words[0];

分配一个新的String,wordI但它只是更改引用的本地(在方法内)副本.原始word1变量仍然引用原始String.

要使其工作,您可以使用数组:

public static void synToWords(String syn, String[] word1And2){
    String[] words = syn.split("\\t");
    word1And2[0] = word1And2[0] + words[0];
    word1And2[1] = word1And2[1] + words[1];
}

并在您的主要代码中:

String[] words = { "", "" };
synToWords(synFR.getLine(3), words);
System.out.println(words[0] +" " + words[1]);

或者你可以简单地返回一个String数组:

public static String[] synToWords(String syn){
    String[] words = syn.split("\\t");
    return new String[] {words[0], words[1]};
}

String[] words = synToWords(synFR.getLine(3));
System.out.println(words[0] +" " + words[1]);