我怎樣才能使，增加了每次但犯規刪除零（0）

Question

嗨，我有這個ID ABCD000000001XYZL

public class SmartCounter { 
public String SmartCounter(String strID){ 
intNumber =Integer.parseInt(strID.replaceAll("\\D+","")); 
intNumber += 1; 
strReturn = "ABCD"+intNumber+"XYZL"; 
(strReturn);   
} 
} 

的ID

我只是問我如何能加1到數字的一部分，它返回到一個字符串不丟失零？ TIA：d

Answer 1

假設id的格式爲

• 4個字母
• 9號
• 4個字母

可以使用正則表達式，遞增數解析它，然後重建。事情是這樣的：

public static void main(String[] args) throws Exception { 
    final Pattern pattern = Pattern.compile("(\\D{4})(\\d{9})(\\D{4})"); 
    final String input = "ABCD000000001XYZL"; 
    final Matcher matcher = pattern.matcher(input); 
    if (matcher.matches()) { 
     final String head = matcher.group(1); 
     final long number = Long.parseLong(matcher.group(2)) + 1; 
     final String tail = matcher.group(3); 
     final String result = String.format("%s%09d%s", head, number, tail); 
     System.out.println(result); 
    } 
} 

您可以使用正則表達式snazzier和Matcher.appendReplacement使代碼短一點;代價是複雜性：

public static void main(String[] args) throws Exception { 
    final Pattern pattern = Pattern.compile("(?<=\\D{4})(\\d{9})(?=\\D{4})"); 
    final String input = "ABCD000000001XYZL"; 
    final Matcher matcher = pattern.matcher(input); 
    final StringBuffer result = new StringBuffer(); 
    if (matcher.find()) { 
     final long number = Long.parseLong(matcher.group(1)) + 1; 
     matcher.appendReplacement(result, String.format("%09d", number)); 
    } 
    matcher.appendTail(result); 
    System.out.println(result); 
} 

Answer 2

看看DecimalFormat我相信你能弄清楚細節你自己

Answer 3

你可以使用String.format(String, Object...)和這樣的事情，

class SmartCounter { 
    private int id = 1; 

    public SmartCounter() { 
     this.id = 1; 
    } 

    public SmartCounter(int id) { 
     this.id = id; 
    } 

    public String smartCounter() { 
     return String.format("ABCD%09dXYZL", id++); 
    } 
} 

，你可以運行像

public static void main(String[] args) { 
    SmartCounter sc = new SmartCounter(); 
    for (int i = 0; i < 3; i++) { 
     System.out.println(sc.smartCounter()); 
    } 
} 

輸出是

ABCD000000001XYZL 
ABCD000000002XYZL 
ABCD000000003XYZL