在正則表達式中使用反向引用來動態替換文本

Question

我想要像整數一樣使用$ 1值。
這個想法是用originaltext中的所有數字替換等價的數組值並創建一個新的文本。
下面的期望結果應該是「這是DBValue4，這是DBValue2，這是DBValue7」
此外，有沒有辦法保存這些反向引用以備後用？

String[] values = {"DBValue0","DBValue1","DBValue2","DBValue3","DBValue4","DBValue5","DBValue6","DBValue7","DBValue8","DBValue9","DBValue10"}; 
String originaltext = "This is 4, This is 2, This is 7"; 
text = originaltext.replaceAll("(\\d)","$1"); 
// want something like 
text = originaltext.replaceAll("(\\d)",values[$1]); 
//or 
text = originaltext.replaceAll("(\\d)",values[Integer.parseInt("$1")]); 

Answer 1

您可以使用Pattern和Matcher像這樣：

public static void main(String[] args) throws Exception { 
    final String[] values = {"DBValue0", "DBValue1", "DBValue2", "DBValue3", "DBValue4", "DBValue5", "DBValue6", "DBValue7", "DBValue8", "DBValue9", "DBValue10"}; 
    final String originaltext = "This is 4, This is 2, This is 7"; 
    final Pattern pattern = Pattern.compile("(?<=This is)\\d++"); 
    final Matcher matcher = pattern.matcher(originaltext); 
    final StringBuffer sb = new StringBuffer(); 
    while (matcher.find()) { 
     System.out.println(matcher.group()); 
     final int index = Integer.parseInt(matcher.group()); 
     matcher.appendReplacement(sb, values[index]); 
    } 
    matcher.appendTail(sb); 
    System.out.println(sb); 
} 

輸出：

4 
2 
7 
This is DBValue4, This is DBValue2, This is DBValue7 

編輯

繼OP的評論是似乎OP需求代替String s的形式爲{name, index}其中「name」是數組的名稱，「index」是該數組中元素的索引。

這很容易通過Map平的陣列來實現的，以使用Map<String, String[]>，然後使用Pattern捕獲第一name則index他們的名字。

public static void main(String[] args) throws Exception { 
    final String[] companies = {"Company1", "Company2", "Company3"}; 
    final String[] names = {"Alice", "Bob", "Eve"}; 
    final String originaltext = "This is {company, 0}, This is {name, 1}, This is {name, 2}"; 
    final Map<String, String[]> values = new HashMap<>(); 
    values.put("company", companies); 
    values.put("name", names); 
    final Pattern pattern = Pattern.compile("\\{([^,]++),\\s*+(\\d++)}"); 
    final Matcher matcher = pattern.matcher(originaltext); 
    final StringBuffer sb = new StringBuffer(); 
    while (matcher.find()) { 
     System.out.println(matcher.group(1)); 
     System.out.println(matcher.group(2)); 
     final int index = Integer.parseInt(matcher.group(2)); 
     matcher.appendReplacement(sb, values.get(matcher.group(1))[index]); 
    } 
    matcher.appendTail(sb); 
    System.out.println(sb); 
} 

輸出：

company 
0 
name 
1 
name 
2 
This is Company1, This is Bob, This is Eve