如何解决Java将增量编号添加到文件中存在的
| 我需要在文件存在之前添加一个增量数字,我知道该如何确认以及如何在末尾添加数字,但是我需要一个每次都增加数字的想法 看这个例如了解我 C:\\ MyFiles \\ File.pdf存在,因此请尝试C:\\ MyFiles \\ File1.pdf 下次 C:\\ MyFiles \\ File2.pdf 不知道如何获得最后的增量 和PLZ看到我的代码,我只能增加一次 int indexOfDot = fName.indexOf(\".\");
//if theres a dot,start one character before it,otherwise,//start at the end of the string
int startIndex = indexOfDot > -1 ? indexOfDot - 1 : fName.length() - 1;
if(indexOfDot > -1)
fileNameSuffix = fName.substring(indexOfDot,fName.length());
//search backward on the name to see if it already
//has a number and count the digits
StringBuffer digits = new StringBuffer();
char character = 0;
for (int i = startIndex; i >= 0; i--)
{
character = fName.charAt(i);
if (Character.isDigit(character))
{
digits.append(character);
}
}
if (digits.length() > 0)
{
//There where already digits in the filename.
//Create a number from the digits and add 1
Integer newNumber =new Integer(Integer.parseInt(digits.toString()) + 1);
//Then append that to the actual filename
String actualFileName = fName.substring(0,startIndex + 1 - digits.length());
rtnNewFileName = actualFileName + newNumber.toString() + fileNameSuffix;
}else
{
//There where no digits in the filename
//Append 1 to the actual filename
String actualFileName = fName.substring(0,startIndex - digits.length());
rtnNewFileName = actualFileName + \"1\" + fileNameSuffix;
}
file.setFileName(rtnNewFileName);
out.println(\"<li>File Uploaded <br/>Form field : uploadfile\"+\"<BR> Uploaded file : \"+file.getFileName()+\" (\"+file.getFileSize()+\" bytes)\"+\"<BR> Content Type : \"+file.getContentType());
//Uses the bean now to store specified by jsp:setProperty at the top.
upBean.store(mrequest,\"uploadfile\");
解决方法
您需要第二次将File2.pdf传递给方法,或检查生成的文件名是否存在,然后使用新文件名重复该方法
顺便说一句,我会为此使用正则表达式:
Pattern p = Pattern.compile(\"(.*?)(\\\\d+)?(\\\\..*)?\");
do{
Matcher m = p.matcher(fName);
if(m.matches()){//group 1 is the prefix,group 2 is the number,group 3 is the suffix
fName = m.group(1) + (m.group(2)==null?1:(Integer.parseInt(m.group(2)) + 1)) + (m.group(3)==null?\"\":m.group(3));
}
}while(new File(fName).exists());//repeat until a new filename is generated
, 如果您想保留不带数字后缀的第一个文件名,则对我有用(根据rachet的回答)
Pattern p = Pattern.compile(\"(.*?)(\\\\d+)?(\\\\..*)?\");
while(new File(pathname).exists()){
Matcher m = p.matcher(pathname);
if(m.matches()){//group 1 is the prefix,group 3 is the suffix
pathname = m.group(1) + (m.group(2)==null?1:(Integer.parseInt(m.group(2)) + 1)) + (m.group(3)==null?\"\":m.group(3));
}
}
, 大家好,我找到了答案,您只需在测试之后加载的每个新文件的前面添加(C0Py0),如果您的文件不存在,则调用方法change();。
<%!
字符串reverseIt(字符串源){
int i,len = source.length();
StringBuffer dest =新的StringBuffer(len);
for (i = (len - 1); i >= 0; i--)
dest.append(source.charAt(i));
return dest.toString();
}
%>
<%!
更改字符串(字符串ffName){
字符串newName,ext,finalName;
字符串invName,增量;
字符串copyf = null;
字符串测试;
int i = 0;
int j = 0;
int incr;
int k = j + 4;
newName = ffName.substring(0,ffName.length()-4);
ext = ffName.substring(ffName.length()-3,ffName.length());
invName=reverseIt(newName);
while(k != invName.length()){
if( invName.substring(j,k).equals(\"yP0C\")){
copyf=invName.substring(0,j);
k=invName.length()-1;
}
else{
j++;
k++;
}
}
increment=reverseIt(copyf);
//System.out.println(increment);
incr=Integer.parseInt(increment);
incr+=1;
newName=newName.substring(0,newName.length()-(j-1));
increment=String.valueOf(incr);
finalName=newName+increment+\".\"+ext;
返回finalName;
}
%>
我希望这将有助于
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