[英]java-Match a regex pattern in a string(listing matching and non-matching parts)
我有一個包含五個字段的csv字符串(3個必填字段和2個可選字段)。 可選字段位於位置3和5。我有一個正則表達式模式來標識雙引號中的字符串
private static final String TEXT_IN_DBL_QUOTES_REGEX="\"([^\"]*)\"";
private static final String rowData="\"Field1\", \"Field2\", , \"Field4\", ";
public static void main(String[] args){
List<String> fields = Lists.newArrayList();
Pattern regex = Pattern.compile(TEXT_IN_DBL_QUOTES_REGEX);
Matcher matcher = regex.matcher(rowData);
while(matcher.find()){
fields.add(matcher.group(1));
}
return fields;
}
My expected result is an array list containing
Field1, Field2, null, Field4, null
but the above is returning
Field1, Field2, Field4
我如何調整上面的代碼以獲得所需的結果?
您可以這樣調整正則表達式:
String TEXT_IN_DBL_QUOTES_REGEX="\"([^\"]*)\"|(?<=,) *(?=,|$)";
String rowData="\"Field1\", \"Field2\", , \"Field4\", ";
List<String> fields = new ArrayList<>();
Pattern regex = Pattern.compile(TEXT_IN_DBL_QUOTES_REGEX);
Matcher matcher = regex.matcher(rowData);
while(matcher.find()) {
fields.add(matcher.group(1));
}
System.out.println (fields);
輸出:
[Field1, Field2, null, Field4, null]
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