Java Sax解析器-无法将XML文件拆分为指定大小
如何读取xml并使用SAX解析器将其拆分为多个文件,我遇到了一些困难。考虑到我们输入了以下生成的XML:Java Sax解析器-无法将XML文件拆分为指定大小,java,xml,parsing,sax,saxparser,Java,Xml,Parsing,Sax,Saxparser,如何读取xml并使用SAX解析器将其拆分为多个文件,我遇到了一些困难。考虑到我们输入了以下生成的XML: <?xml version="1.0" encoding="utf-8"?> <record-table> <record> <record_id>12345</record_id> <record_rows> <record_row>str1234</record_ro
<?xml version="1.0" encoding="utf-8"?>
<record-table>
<record>
<record_id>12345</record_id>
<record_rows>
<record_row>str1234</record_row>
</record_rows>
</record>
<footer>
<record_count>12345</record_count>
<record_row_count>12345</record_row_count>
</footer>
</record-table>
此时此刻,我多次尝试读取它,程序执行,但没有执行任何操作 守则草案:
public static void splitXML(File fileToSplit, int splitFileSize) {
try {
SAXParserFactory factory = SAXParserFactory.newInstance();
SAXParser parser = factory.newSAXParser();
XMLReader reader = parser.getXMLReader();
reader.parse(new InputSource(new FileInputStream(fileToSplit)));
reader.setContentHandler(new DefaultHandler() {
public static final String DIRECTORY = "target/results";
private int fileSize = 0;
private File fileLocation;
// counts number of files created
private int fileCount = 0;
// counts characters to decide where to split file
private long charCount = 0;
// data line buffer (is reset when the file is split)
private StringBuilder recordRowDataLines = new StringBuilder();
// temporary variables used for the parser events
private String currentElement = null;
private String currentRecordId = null;
private String currentRecordRowData = null;
public final long TAG_CHAR_SIZE = 5;
@Override
public void startDocument() throws SAXException {
File directory = new File(DIRECTORY);
if(!directory.exists())
directory.mkdir();
}
@Override
public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
currentElement = qName;
}
@Override
public void endElement(String uri, String localName, String qName) throws SAXException {
if(qName.equals("record_rows")) {
try {
savePatch();
} catch (IOException e) {
throw new SAXException(e);
}
}
if (qName.equals("record_row")) { // one record finished - save in buffer & calculate size so far
charCount += tagSize("record_row");
recordRowDataLines.append("<record_row>")
.append(currentRecordRowData)
.append("</record_row>");
if (charCount >= fileSize) { // if max size was reached, save what was read so far in a new file
try {
savePatch();
} catch (IOException ex) {
throw new SAXException(ex);
}
}
}
currentElement = null;
}
@Override
public void characters(char[] ch, int start, int length) throws SAXException {
System.out.println(new String(ch, start, length));
if (currentElement == null) {
return;
}
if (currentElement.equals("record_id")) {
currentRecordId = new String(ch, start, length);
}
if (currentElement.equals("record_row")) {
currentRecordRowData = new String(ch, start, length);
charCount += currentRecordRowData.length(); // storing size so far
}
}
public long tagSize(String tagName) {
return TAG_CHAR_SIZE + tagName.length() * 2; // size of text + tags
}
public void savePatch() throws IOException {
++fileCount;
StringBuilder stringBuilder = new StringBuilder();
stringBuilder.append("<record part='")
.append(fileCount)
.append("'><record_id>")
.append(currentRecordId)
.append("</record_id>")
.append("<record_rows>")
.append(recordRowDataLines)
.append("</record_rows></record>");
File fragment = new File(DIRECTORY, "data_part_" + fileCount + ".xml");
System.out.println("File " + fragment.getAbsolutePath() + "has been saved!");
try(FileWriter out = new FileWriter(fragment)){
out.write(stringBuilder.toString());
} catch (Exception e) {
e.printStackTrace();
}
//flush current information that was saved.
recordRowDataLines = new StringBuilder();
charCount = 0;
}
});
} catch (ParserConfigurationException | SAXException | IOException e) {
e.printStackTrace();
}
}
主类外观:
public class Main {
public static void main(String[] args) {
System.out.println("Welcome!");
<omitted>
File f = CommonUtils.requestFilePath();
int fileSize = CommonUtils.requestUserValueInt("Enter file split size : ");
XMLSplitter.splitXML(f, fileSize);
}
}
请你看看,我看不到的。请提供帮助。您应该在解析之前调用setContentHandler。程序会执行,但不会执行任何操作,因为范围太广。你调试代码了吗?你应该缩小范围,给我们一个更具体的问题描述。您不应该将XML创建为普通字符串。你有没有想过逃离特殊角色?改用。是的,我做了调试,一切都很好。这就是我喝咖啡的原因。现在,我不知道如何将footer元素与实际元素计数一起附加到每个分割的文件中……程序执行了两条语句,但没有执行任何操作,是的,我进行了调试,一切都很好。是矛盾的。SAX是必需的吗?在我看来,如果您不局限于SAX,那么这样做可能会更快/更简单
public class Main {
public static void main(String[] args) {
System.out.println("Welcome!");
<omitted>
File f = CommonUtils.requestFilePath();
int fileSize = CommonUtils.requestUserValueInt("Enter file split size : ");
XMLSplitter.splitXML(f, fileSize);
}
}