以下关于边界匹配器正则表达式的代码片段存在问题 (\b)

我的输入：

 1. end 
 2. end of the day or end of the week 
 3. endline
 4. something 
 5. "something" end

根据上述讨论，如果我尝试使用此代码片段替换单个字符串，它会成功从该行中删除适当的单词

public class DeleteTest {

    public static void main(String[] args) {

        // TODO Auto-generated method stub
        try {
        File file = new File("C:/Java samples/myfile.txt");
        File temp = File.createTempFile("myfile1", ".txt", file.getParentFile());
        String delete="end";
        BufferedReader reader = new BufferedReader(new InputStreamReader(new FileInputStream(file)));
        PrintWriter writer = new PrintWriter(new OutputStreamWriter(new FileOutputStream(temp)));

        for (String line; (line = reader.readLine()) != null;) {
            line = line.replaceAll("\\b"+delete+"\\b", "");
       writer.println(line);
        }
        reader.close();
        writer.close();
        }
        catch (Exception e) {
            System.out.println("Something went Wrong");
        }
    }
}

我的输出如果我使用上面的代码片段：（也是我的预期输出）

 1.  
 2. of the day or of the week
 3. endline
 4. something
 5. "something"

但是，当我包含更多要删除的单词时，并且为此目的，当我使用 Set 时，我使用以下代码片段：

public static void main(String[] args) {

    // TODO Auto-generated method stub
    try {

    File file = new File("C:/Java samples/myfile.txt");
    File temp = File.createTempFile("myfile1", ".txt", file.getParentFile());
    BufferedReader reader = new BufferedReader(new InputStreamReader(new FileInputStream(file)));
    PrintWriter writer = new PrintWriter(new OutputStreamWriter(new FileOutputStream(temp)));

        Set<String> toDelete = new HashSet<>();
        toDelete.add("end");
        toDelete.add("something");

    for (String line; (line = reader.readLine()) != null;) {
        line = line.replaceAll("\\b"+toDelete+"\\b", "");
    writer.println(line);
    }
    reader.close();
    writer.close();
    }
    catch (Exception e) {
        System.out.println("Something went Wrong");
    }
}

我的输出为：（它只是删除了空格）

 1. end
 2. endofthedayorendoftheweek
 3. endline
 4. something
 5. "something" end 

你们能帮我解决这个问题吗？

单击此处关注该主题 https://stackoverflow.com/questions/43832915/how-to-remove-a-particular-string-in-a-text-file-using-java

您需要创建一个交替组 http://www.regular-expressions.info/alternation.html出组与

String.join("|", toDelete)

并用作

line = line.replaceAll("\\b(?:"+String.join("|", toDelete)+")\\b", "");

图案看起来像

\b(?:end|something)\b

See the 正则表达式演示 https://regex101.com/r/Bfjwx2/1. Here, (?:...) is a 非捕获习惯于group几种替代方案，无需为捕获创建内存缓冲区（您不需要它，因为您删除了匹配项）。

或者，更好的是，在进入循环之前编译正则表达式：

Pattern pat = Pattern.compile("\\b(?:" + String.join("|", toDelete) + ")\\b");
...
    line = pat.matcher(line).replaceAll("");

UPDATE:

要允许匹配可能包含特殊字符的整个“单词”，您需要Pattern.quote这些单词要转义那些特殊字符，然后您需要使用明确的单词边界，(?<!\w)而不是最初的\b确保 and 之前没有单词 char(?!\w)负前瞻而不是最终\b确保匹配后没有单词字符。

在 Java 8 中，您可以使用以下代码：

Set<String> nToDel = new HashSet<>();
nToDel = toDelete.stream()
    .map(Pattern::quote)
    .collect(Collectors.toCollection(HashSet::new));
String pattern = "(?<!\\w)(?:" + String.join("|", nToDel) + ")(?!\\w)";

正则表达式看起来像(?<!\w)(?:\Q+end\E|\Qsomething-\E)(?!\w) https://regex101.com/r/Bfjwx2/2。注意之间的符号\Q and \E被解析为文字符号.