按XML標記分割文件

Question

我是Java編碼的業餘愛好者，我被困在一個任務中。除了基本部分外，我已經寫了大部分代碼，並且我正在如何着手做這件事。我希望有人能指導我如何完成正確的方向。

我做了一個叫Splitter的課。它的工作是讀取XML文件並根據特定的XML start和end標籤將其分割成更小的文件，而每個較小的文件也必須小於給定的maxfilesize。

此外，必須將舊版本的文件放入具有時間戳的歸檔文件夾中。我主要得到它。除此之外，我不知道如何通過start和end標籤進行分割。我有一個getXML方法讀取這些標籤之間的所有內容;但是從那裏開始，當我將它稱爲拆分方法時，我不太確定如何處理它。

任何人有任何可以分享的信息來引導我走向正確的方向嗎？

public class Splitter { 

    public static void split(String directory, String fileName, 
     String transactionTag, int fileSize) throws IOException{ 
    String startTag = "<"+ transactionTag + ">"; 
    String endTag = "</"+ transactionTag + ">"; 
    File f = new File(directory + fileName); 
    File output = new File (directory + "Output/" + fileName); 
    BufferedInputStream in = new BufferedInputStream(new FileInputStream(f)); 
    Splitter sp = new Splitter(); 
    int fileCount = 0; 
    int len; 
    int maxFileSize = fileSize; 
    byte[] buf = new byte[maxFileSize]; 
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy_MM_dd_hh_mm_ss"); 
    Date curDate = new Date(); 
    String strDate = sdf.format(curDate); 
    String fileTime = strDate; 
    while ((len = in.read(buf)) > 0) { 
     fileCount++; 
     try{ 
      File afile =new File(directory + "Output\\" + fileName + "." + fileCount); 
      if(afile.exists()){ 
       if(afile.renameTo(new File(directory + "Output\\Archive\\" + fileName + "." + fileCount + "-" + fileTime))){ 
       }else{ 
        System.out.println("Files failed to be archived. "); 
       } 
      }else{ 
       System.out.println("This file does not exist."); 
      } 
     }catch(Exception e){ 
      e.printStackTrace(); 
     } 
     BufferedOutputStream out = new BufferedOutputStream(new FileOutputStream(output + "." + fileCount)); 
     String newInput = new String(buf,0,len); // newInput is a String no greater in length than whatever bytes or chars 
     String value = sp.getXML(newInput, transactionTag); 

     //This part is incomplete. 
     //Do something with value to make this class split the file by XML tags. 
     //Also make sure any left over code before the first start tag and last end tag are also put into smaller files. 

     int start = value.indexOf(startTag); 
     int end = value.lastIndexOf(endTag); 

     out.write(buf,0,len); 
     out.close(); 
    } 
    in.close(); 
    } 
    public String getXML(String content, String tagName){ 
    String startTag = "<"+ tagName + ">"; 
    String endTag = "</"+ tagName + ">"; 
    int startposition = content.indexOf(startTag); 
    int endposition = content.indexOf(endTag, startposition); 
    if (startposition == -1)return ""; 
    startposition += startTag.length(); 
    if(endposition == -1) return ""; 
    return content.substring(startposition, endposition); 
    } 
    public static void main(String[]args) throws IOException{ 
    int num = 100; 
    int kb = num * 1024; 
    Splitter split = new Splitter(); 
    split("C:/SplitUp/", "fileSplit.xml", "blah1", kb); 
    System.out.println("Program ran"); 
    } 
} 

Answer 1

基於您的評論，我假設你fileSplit.xml看起來是這樣的：

<header> 
    <!-- Some XML metadata --> 
<header> 
<start> 
    <!-- Some XML data --> 
</start> 
<start> 
    <!-- Some XML data --> 
</start> 
<start> 
    <!-- Some XML data --> 
</start> 
<start> 
    <!-- Some XML data --> 
</start> 
<footer> 
    <!-- Some XML metadata --> 
<footer> 

其中每個<start>，<header>，<footer>及其相應的結束標記都是靠自己行。

您可以使用簡化代碼：

1. java.nio.files.readAllLines(Path path, Charset cs)讀你C:/SplitUp/fileSplit.xml
2. java.io.FileWriter寫信給所有子文件。

本質（用於Java 7+），你可以這樣做，

// read the entire fileSplit.xml into an array of string 
List<String> fileContent = files.readAllLines(Paths.get("C:/SplitUp/fileSplit.xml"), StandardCharsets.UTF_8); 

// iterate through the array to split the file content into sub-files 
String subFileContent = ""; 
for(String line : fileContent){ 
    if(line.compareToIgnoreCase("<start>") != 0 || line.compareToIgnoreCase("<footer>") != 0) { // keep reading if this line isn't a <start> nor a <footer> 
    subFileContent += line; 
    } 
    else { // if this line is a <start> or a <footer>, write all the content thus-far into a new sub-file 
    // sub-files names taken from your codes above. Make sure they are unique! 
    FileWriter fileWriter = new FileWriter(directory + "Output\\" + fileName + "." + fileCount++); 

    // this will write up to only maxFileSize number of characters. 
    // how do you want to handle spillover? 
    fileWriter.write(subFileContent, 0, maxFileSize); 

    // reset subFileContent 
    subFileContent = new String(line); 
    } 
} 

在滿足

的要求方面......每個小文件也必須小於給定maxfilesize

您可以將最後的else更改爲else if爲f當其length()超出maxFileSize時，請將subFileContent寫出來，並確保餘數寫入第二個子文件。但是，我要說的是，在處理第二個需求之前，先將內容分解成子文件，然後再開始工作。