Question

我们有一个场景，我们需要在小块中拆分大小超过10GB的大型xml文件。每个块应包含100或200个元素。示例xml

<Employees>
  <Employee id="1">
    <age>29</age>
    <name>Pankaj</name>
    <gender>Male</gender>
    <role>Java Developer</role>
  </Employee>
  <Employee id="3">
    <age>35</age>
    <name>Lisa</name>
    <gender>Female</gender>
    <role>CEO</role>
  </Employee>
  <Employee id="3">
    <age>40</age>
    <name>Tom</name>
    <gender>Male</gender>
    <role>Manager</role>
  </Employee>
  <Employee id="3">
    <age>25</age>
    <name>Meghna</name>
    <gender>Female</gender>
    <role>Manager</role>
  </Employee>
  <Employee id="3">
    <age>29</age>
    <name>Pankaj</name>
    <gender>Male</gender>
    <role>Java Developer</role>
  </Employee>
  <Employee id="3">
    <age>35</age>
    <name>Lisa</name>
    <gender>Female</gender>
    <role>CEO</role>
  </Employee>
  <Employee id="3">
    <age>40</age>
    <name>Tom</name>
    <gender>Male</gender>
    <role>Manager</role>
 </Employee>
</Employees>

我有Stax解析器代码，它会将文件分成小块。但是每个文件只包含一个完整的Employee元素，我需要在单个文件中包含100或200个或更多<Employee>个元素。这是我的java代码

public static void main(String[] s) throws Exception{
     String prefix = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"+"\n";
        String suffix = "\n</Employees>\n";
        int count=0;
        try {

        int i=0;
             XMLInputFactory xif = XMLInputFactory.newInstance();
             XMLStreamReader xsr = xif.createXMLStreamReader(new FileReader("D:\\Desktop\\Test\\latestxml\\test.xml"));
             xsr.nextTag(); // Advance to statements element

             TransformerFactory tf = TransformerFactory.newInstance();
             Transformer t = tf.newTransformer();
             while(xsr.nextTag() == XMLStreamConstants.START_ELEMENT) {
                 File file = new File("C:\\Users\\test\\Desktop\\xml\\"+"out"  +i+ ".xml");
                 FileOutputStream fos=new FileOutputStream(file,true);
                 t.transform(new StAXSource(xsr), new StreamResult(fos));
                 i++;

             }

        } catch (Exception e) {
            e.printStackTrace();
        }

Answer 1

不要在每次迭代时使用i，当迭代次数达到100或200时，应该使用最新计数进行更新

像：

String outputPath = "/test/path/foo.txt";

    while(xsr.nextTag() == XMLStreamConstants.START_ELEMENT) {

                    FileOutputStream file = new FileOutputStream(outputPath,true);
                     ... 
                     ...
                     count ++; 
                     if(count == 100){
                      i++;
                      outputPath = "/test/path/foo"+i+"txt";
                      count = 0;
                      }  
                 }

Answer 2

我希望我做得对，但每次添加一个雇主时你只需要增加计数

        File file = new File("out" + i + ".xml");
        FileOutputStream fos = new FileOutputStream(file, true);
        appendStuff("<Employees>",file);
        while (xsr.nextTag() == XMLStreamConstants.START_ELEMENT) {
            count++;
            t.transform(new StAXSource(xsr), new StreamResult(fos));
            if(count == 100) {
                count = 0;
                i++;
                appendStuff("</Employees>",file);
                fos.close();
                file = new File("out" + i + ".xml");
                fos = new FileOutputStream(file, true);
                appendStuff("<Employees>",file);
            }
        }

它不是很好，但你明白了

private static void appendStuff(String content, File file) throws IOException {
    FileWriter fw = new FileWriter(file.getAbsoluteFile(),true);
    BufferedWriter bw = new BufferedWriter(fw);
    bw.write(content);
    bw.close();
}

使用Stax Parser将巨大的xml文件＆gt; 10GB拆分成小块

2 个答案: