How to determine whether a given string is an .xml file - java

I have an issue that I get some some response as a String.
This String could be a normal string,number etc.. or an .xml file.
Now ,when I get an xml file, I want to treat it differently.
I am not able to distinguish between a string or an .xml file.
Also, this xml file could have some syntatic error.
Please suggest , how do I go ahead
Code is like this:
Document document = reader.read(new StringReader(xml));
where xml can be a string or an xml file itself.
If xml is a string , it is fine but if it is an xml file and with some syntax error then it should throw exception

If it is a proper XML document it should begin with a XML declaration. If that's there, it's intended to be a conforming XML document. If that's not there it cannot be a conforming XML document.

If you are using a coding language like C#, then you can use - XmlDocument.loadxml -
http://msdn.microsoft.com/en-us/library/system.xml.xmldocument.loadxml.aspx
This will throw error if the string is not in correct xml format.

Related

How to stop Jackson from parsing an element?

I have a XML Document where there are nested tags that should not be interpreted as XML tags
For example something like this
<something>cbaabc</something> should be parsed as a plain String "cbaabc" (it should be mentioned that the document has other elements as well that get parsed just fine). Jackson tho tries to interpret it as an Object and I don't know how to prevent this. I tried using #JacksonXmlText, turning off wrapping and a custom Deserializer, but I didn't get it to work.
The <a should be translated to <a. This back and forth conversion normally happens with every XML API, setting and getting text will use those entities &...;.
An other option is to use an additional CDATA section: <![CDATA[ ... ]]>.
<something><![CDATA[cbaabc]]></something>
If you cannot correct that, and have to live with an already corrupted XML text, you must do your own hack:
Load the wrong XML in a String
Repair the XML
Pass the XML string to jackson
Repairing:
String xml = ...
xml = xml.replaceAll("<(/?a\\b[^>]*)>", "<$1>"); // Links
StringReader in = new StringReader(xml);

How to convert nested tags in dynamic XML into a for loop?

I want to convert dynamic xml file into a specific file format. i could able to parse the xml using jsoup parser but the problem is I want to parse the nested tags and put it into a for-loop.Is there any way to do it. Attaching the sample below for reference
Input XML(sample)
<lineComponents>
<invoiceComponents>
<invoiceComponent>
<type></type>
<name></name>
<amount>16.00</amount>
<taxPercentage>0.00</taxPercentage>
<taxAmount>0E-8</taxAmount>
</invoiceComponent>
</invoiceComponents>
<acctComponents>
<acctComponent>
<componentCode>BASE</componentCode>
<glAccountNr></glAccountNr>
<baseAmount>10.00000</baseAmount>
<taxRate>0.00</taxRate>
<taxAmount>0.00000</taxAmount>
<totalAmount>10.00000</totalAmount>
<isVAT>No</isVAT>
</acctComponent>
<acctComponent>
<componentCode></componentCode>
<glAccountNr></glAccountNr>
<baseAmount>3.00000</baseAmount>
<taxRate>0.00</taxRate>
<taxAmount>0.00000</taxAmount>
<totalAmount>3.00000</totalAmount>
<isVAT>No</isVAT>
</acctComponent>
<acctComponent>
<componentCode>DISC</componentCode>
<glAccountNr></glAccountNr>
<baseAmount>-2.00000</baseAmount>
<taxRate>0.00</taxRate>
<taxAmount>0.00000</taxAmount>
<totalAmount>-2.00000</totalAmount>
<isVAT>No</isVAT>
</acctComponent>
<acctComponent>
<componentCode>ARPIT</componentCode>
<glAccountNr></glAccountNr>
<baseAmount>5.00000</baseAmount>
<taxRate>0.00</taxRate>
<taxAmount>0.00000</taxAmount>
<totalAmount>5.00000</totalAmount>
<isVAT>No</isVAT>
</acctComponent>
</acctComponents>
</lineComponents>
Expected output:
for(OrderItem invoiceLineItem: orderLineWrp.invoiceLineItems){
Dom.XMLNode invoiceComponentNode = invoiceComponentsNode.addChildElement(EP_OrderConstant.invoiceComponent,null,null);
invoiceComponentNode.addChildElement(EP_OrderConstant.seqId,null,null).addTextNode(getValueforNode(invoiceLineItem.EP_SeqId__c));
invoiceComponentNode.addChildElement(EP_OrderConstant.TYPE,null,null).addTextNode(getValueforNode(invoiceLineItem.EP_ChargeType__c));
invoiceComponentNode.addChildElement(EP_OrderConstant.name,null,null).addTextNode(getValueforNode(invoiceLineItem.EP_Invoice_Name__c));
invoiceComponentNode.addChildElement(EP_OrderConstant.amount,null,null).addTextNode(getValueforNode(invoiceLineItem.UnitPrice)); //Value for amount
invoiceComponentNode.addChildElement(EP_OrderConstant.taxPercentage,null,null).addTextNode(getValueforNode(invoiceLineItem.EP_Tax_Percentage__c)); //Value for taxPercentage
invoiceComponentNode.addChildElement(EP_OrderConstant.taxAmount,null,null).addTextNode(getValueforNode(invoiceLineItem.EP_Tax_Amount_XML__c)); //Value for taxAmount
}
This Xml file is dynamic. Is there any way to handle dynamic XML file into a specific format like above?
Jsoup is rather for HTML parsing.
If you have XSD/DTD to your XML, you should use JAXB-generated classes and an unmarshaller to read it.
Otherwise you can use JAXP (DOMParser, if the file is small, and XPath, or event based SAXParser(however this is not so easy to use) for really large XML files).

Is there any way to process my rest of xml file despite of any fatal error like SAXParserException encountered [duplicate]

Currently, I'm working on a feature that involves parsing XML that we receive from another product. I decided to run some tests against some actual customer data, and it looks like the other product is allowing input from users that should be considered invalid. Anyways, I still have to try and figure out a way to parse it. We're using javax.xml.parsers.DocumentBuilder and I'm getting an error on input that looks like the following.
<xml>
...
<description>Example:Description:<THIS-IS-PART-OF-DESCRIPTION></description>
...
</xml>
As you can tell, the description has what appears to be an invalid tag inside of it (<THIS-IS-PART-OF-DESCRIPTION>). Now, this description tag is known to be a leaf tag and shouldn't have any nested tags inside of it. Regardless, this is still an issue and yields an exception on DocumentBuilder.parse(...)
I know this is invalid XML, but it's predictably invalid. Any ideas on a way to parse such input?
That "XML" is worse than invalid – it's not well-formed; see Well Formed vs Valid XML.
An informal assessment of the predictability of the transgressions does not help. That textual data is not XML. No conformant XML tools or libraries can help you process it.
Options, most desirable first:
Have the provider fix the problem on their end. Demand well-formed XML. (Technically the phrase well-formed XML is redundant but may be useful for emphasis.)
Use a tolerant markup parser to cleanup the problem ahead of parsing as XML:
Standalone: xmlstarlet has robust recovering and repair capabilities credit: RomanPerekhrest
xmlstarlet fo -o -R -H -D bad.xml 2>/dev/null
Standalone and C/C++: HTML Tidy works with XML too. Taggle is a port of TagSoup to C++.
Python: Beautiful Soup is Python-based. See notes in the Differences between parsers section. See also answers to this question for more
suggestions for dealing with not-well-formed markup in Python,
including especially lxml's recover=True option.
See also this answer for how to use codecs.EncodedFile() to cleanup illegal characters.
Java: TagSoup and JSoup focus on HTML. FilterInputStream can be used for preprocessing cleanup.
.NET:
XmlReaderSettings.CheckCharacters can
be disabled to get past illegal XML character problems.
#jdweng notes that XmlReaderSettings.ConformanceLevel can be set to
ConformanceLevel.Fragment so that XmlReader can read XML Well-Formed Parsed Entities lacking a root element.
#jdweng also reports that XmlReader.ReadToFollowing() can sometimes
be used to work-around XML syntactical issues, but note
rule-breaking warning in #3 below.
Microsoft.Language.Xml.XMLParser is said to be “error-tolerant”.
Go: Set Decoder.Strict to false as shown in this example by #chuckx.
PHP: See DOMDocument::$recover and libxml_use_internal_errors(true). See nice example here.
Ruby: Nokogiri supports “Gentle Well-Formedness”.
R: See htmlTreeParse() for fault-tolerant markup parsing in R.
Perl: See XML::Liberal, a "super liberal XML parser that parses broken XML."
Process the data as text manually using a text editor or
programmatically using character/string functions. Doing this
programmatically can range from tricky to impossible as
what appears to be
predictable often is not -- rule breaking is rarely bound by rules.
For invalid character errors, use regex to remove/replace invalid characters:
PHP: preg_replace('/[^\x{0009}\x{000a}\x{000d}\x{0020}-\x{D7FF}\x{E000}-\x{FFFD}]+/u', ' ', $s);
Ruby: string.tr("^\u{0009}\u{000a}\u{000d}\u{0020}-\u{D7FF}\u{E000‌​}-\u{FFFD}", ' ')
JavaScript: inputStr.replace(/[^\x09\x0A\x0D\x20-\xFF\x85\xA0-\uD7FF\uE000-\uFDCF\uFDE0-\uFFFD]/gm, '')
For ampersands, use regex to replace matches with &: credit: blhsin, demo
&(?!(?:#\d+|#x[0-9a-f]+|\w+);)
Note that the above regular expressions won't take comments or CDATA
sections into account.
A standard XML parser will NEVER accept invalid XML, by design.
Your only option is to pre-process the input to remove the "predictably invalid" content, or wrap it in CDATA, prior to parsing it.
The accepted answer is good advice, and contains very useful links.
I'd like to add that this, and many other cases of not-wellformed and/or DTD-invalid XML can be repaired using SGML, the ISO-standardized superset of HTML and XML. In your case, what works is to declare the bogus THIS-IS-PART-OF-DESCRIPTION element as SGML empty element and then use eg. the osx program (part of the OpenSP/OpenJade SGML package) to convert it to XML. For example, if you supply the following to osx
<!DOCTYPE xml [
<!ELEMENT xml - - ANY>
<!ELEMENT description - - ANY>
<!ELEMENT THIS-IS-PART-OF-DESCRIPTION - - EMPTY>
]>
<xml>
<description>blah blah
<THIS-IS-PART-OF-DESCRIPTION>
</description>
</xml>
it will output well-formed XML for further processing with the XML tools of your choice.
Note, however, that your example snippet has another problem in that element names starting with the letters xml or XML or Xml etc. are reserved in XML, and won't be accepted by conforming XML parsers.
IMO these cases should be solved by using JSoup.
Below is a not-really answer for this specific case, but found this on the web (thanks to inuyasha82 on Coderwall). This code bit did inspire me for another similar problem while dealing with malformed XMLs, so I share it here.
Please do not edit what is below, as it is as it on the original website.
The XML format, requires to be valid a unique root element declared in the document.
So for example a valid xml is:
<root>
<element>...</element>
<element>...</element>
</root>
But if you have a document like:
<element>...</element>
<element>...</element>
<element>...</element>
<element>...</element>
This will be considered a malformed XML, so many xml parsers just throw an Exception complaining about no root element. Etc.
In this example there is a solution on how to solve that problem and succesfully parse the malformed xml above.
Basically what we will do is to add programmatically a root element.
So first of all you have to open the resource that contains your "malformed" xml (i. e. a file):
File file = new File(pathtofile);
Then open a FileInputStream:
FileInputStream fis = new FileInputStream(file);
If we try to parse this stream with any XML library at that point we will raise the malformed document Exception.
Now we create a list of InputStream objects with three lements:
A ByteIputStream element that contains the string: <root>
Our FileInputStream
A ByteInputStream with the string: </root>
So the code is:
List<InputStream> streams =
Arrays.asList(
new ByteArrayInputStream("<root>".getBytes()),
fis,
new ByteArrayInputStream("</root>".getBytes()));
Now using a SequenceInputStream, we create a container for the List created above:
InputStream cntr =
new SequenceInputStream(Collections.enumeration(str));
Now we can use any XML Parser library, on the cntr, and it will be parsed without any problem. (Checked with Stax library);

Generating XSL stylesheet in java (xml to xml)

i need a java code which makes an xsl style sheet that transforms an xml file to another xml file. but it should be dynamic.
i want to set the xsl:element names and path. and the java code should generate
me automaticly.
i have made one but if i want to change my type of xml, i need to add like 30 line code.
example from my code;
string xslelementstart = "<xsl:element name=\"" ;
string elementend="</xsl:element>";
string value="<xsl:value-of select=\"";
string name = "";(will be public and can be changed)
string path = "";(will be public and can be changed)
string end="\"\>";
string end2="\">";
if(path!="")
{
string xsl = xslelementstart+name+end2+"\n"+
value+path+end+"\n"
elementend
}
this is an example of my java code not the actual. im working with a big xml file. i want other xml files to be in my xml file format.but if i want to change my xml file (like adding another element) this code is not useful.as i said i should only set the values of my xml file and the java code should generates me. is it possible?
String concatenation is ugly, use Document Builder.
See the similar question: Create xslt files programmatically

Parsing string to extract XML

Lets say I have the following String:
abc: def
qxy
<?xml version='1.0'><xyz>
...
</xyz>
other text
<?xml version='1.0'><www>
...
</www>
more text
Is there a way to parse this? I am currently trying with an XMLStreamReader and it throws a parsing error: javax.xml.stream.XMLStreamException: ParseError. If I remove all the test and just try to parse one of the XML sections (like only xyz) then it works perfectly.
You have to filter out the xml part. No general purpose XMLStreamReader will do it for you since they have no idea where your document starts or ends. You may craft your own specialized version that can filter the input, but other implementations expect a full xml document only.

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