I'm looking for a CSS Parser in java. In particular my requirement is, for a given node/element in an HTML document, to be able to ask/get the css styles for that element from the Parser.
I know there is the W3C SAC interface and one or 2 implementations based on this - but turorials/examples appear non-existant.
Any help/points in right direction much appreciated.
Thanks
I've used CSSParser and I like it- it gives good feedback on errors as well.
Here's some sample code I've found and modified:
package com.dlogic;
import com.steadystate.css.parser.CSSOMParser;
import org.w3c.css.sac.InputSource;
import org.w3c.dom.css.CSSStyleSheet;
import org.w3c.dom.css.CSSRuleList;
import org.w3c.dom.css.CSSRule;
import org.w3c.dom.css.CSSStyleRule;
import org.w3c.dom.css.CSSStyleDeclaration;
import java.io.*;
public class CSSParserTest
{
protected static CSSParserTest oParser;
public static void main(String[] args) {
oParser = new CSSParserTest();
if (oParser.Parse("design.css")) {
System.out.println("Parsing completed OK");
} else {
System.out.println("Unable to parse CSS");
}
}
public boolean Parse(String cssfile)
{
FileOutputStream out = null;
PrintStream ps = null;
boolean rtn = false;
try
{
// cssfile accessed as a resource, so must be in the pkg (in src dir).
InputStream stream = oParser.getClass().getResourceAsStream(cssfile);
// overwrites and existing file contents
out = new FileOutputStream("log.txt");
if (out != null)
{
//log file
ps = new PrintStream( out );
System.setErr(ps); //redirects stderr to the log file as well
} else {
return rtn;
}
InputSource source = new InputSource(new InputStreamReader(stream));
CSSOMParser parser = new CSSOMParser();
// parse and create a stylesheet composition
CSSStyleSheet stylesheet = parser.parseStyleSheet(source, null, null);
//ANY ERRORS IN THE DOM WILL BE SENT TO STDERR HERE!!
// now iterate through the dom and inspect.
CSSRuleList ruleList = stylesheet.getCssRules();
ps.println("Number of rules: " + ruleList.getLength());
for (int i = 0; i < ruleList.getLength(); i++)
{
CSSRule rule = ruleList.item(i);
if (rule instanceof CSSStyleRule)
{
CSSStyleRule styleRule=(CSSStyleRule)rule;
ps.println("selector:" + i + ": " + styleRule.getSelectorText());
CSSStyleDeclaration styleDeclaration = styleRule.getStyle();
for (int j = 0; j < styleDeclaration.getLength(); j++)
{
String property = styleDeclaration.item(j);
ps.println("property: " + property);
ps.println("value: " + styleDeclaration.getPropertyCSSValue(property).getCssText());
ps.println("priority: " + styleDeclaration.getPropertyPriority(property));
}
}// end of StyleRule instance test
} // end of ruleList loop
if (out != null) out.close();
if (stream != null) stream.close();
rtn = true;
}
catch (IOException ioe)
{
System.err.println ("IO Error: " + ioe);
}
catch (Exception e)
{
System.err.println ("Error: " + e);
}
finally
{
if (ps != null) ps.close();
}
return rtn;
}
}
A CSS library for reading and writing CSS2 and CSS3 files in Java is ph-css from https://github.com/phax/ph-css It is based on a JavaCC grammar and supports both CSS2 as well as CSS3 and additionally lets you parse HTML style attributes.
Since May 21st, 2013 a JDK 1.5 version is also available, which makes it more interesting for Android development
I needed a CSS parser for an own project, but I found "CSSParser" to be too tedious and inflexible to work with (but that could have just been me), so I ended up writing my own simple but functional CSS parser.
Feel free to use it if you want to :-)
Check out SAC and its implementstions here: http://www.w3.org/Style/CSS/SAC/
CSSParser is a little bit out of date
I just rolled out my own CSS Stream Parser for Java, available on github. What sets this parser apart includes:
TokenSequence and Token simplify processes for handling selectors, etc.jStyleParser provides exactly this functionality. It parses all the referenced style sheets and maps them to the DOM tree nodes.
If you struggle with CSSParser, because there seems to be no documentation at all, and you perhaps want to parse just a CSS String, like value from style parameter, here is my simple sample of use:
import org.junit.Test;
import org.w3c.css.sac.InputSource;
import org.w3c.dom.css.CSSRule;
import org.w3c.dom.css.CSSStyleDeclaration;
import org.w3c.dom.css.CSSValue;
import com.steadystate.css.parser.CSSOMParser;
public class ParseCssTest {
@Test
public void testParseStyleDeclaration() throws IOException {
String cssSample = "margin-top: 0cm; margin-bottom: 0cm; background: #e6e6e6";
CSSOMParser parser = new CSSOMParser();
CSSStyleDeclaration o = parser.parseStyleDeclaration(new InputSource(new StringReader(cssSample)));
assertEquals("margin-top: 0cm; margin-bottom: 0cm; background: rgb(230, 230, 230)", o.toString());
assertEquals("0cm", o.getPropertyCSSValue("margin-bottom").toString());
assertEquals("0cm", o.getPropertyCSSValue("margin-bottom").getCssText());
assertEquals(null, o.getPropertyCSSValue("foo"));
}
@Test
public void testParseARule() throws IOException {
String cssSample = "r1 { margin-top: 0cm; margin-bottom: 0cm; background: #e6e6e6 }";
CSSOMParser parser = new CSSOMParser();
CSSRule o = parser.parseRule(new InputSource(new StringReader(cssSample)));
assertEquals("r1 { margin-top: 0cm; margin-bottom: 0cm; background: rgb(230, 230, 230) }", o.toString());
}
@Test
public void parseStyleDeclarationWithAdvancedTests() throws IOException {
String cssSample = "margin-top: 0 cm; margin-bottom: 0cm; background: #e6e6e6";
CSSOMParser parser = new CSSOMParser();
CSSStyleDeclaration o = parser.parseStyleDeclaration(new InputSource(new StringReader(cssSample)));
assertEquals("margin-top: 0 cm; margin-bottom: 0cm; background: rgb(230, 230, 230)", o.toString());
assertEquals("0cm", o.getPropertyCSSValue("margin-bottom").toString());
assertEquals("0cm", o.getPropertyCSSValue("margin-bottom").getCssText());
assertEquals(CSSValue.CSS_VALUE_LIST, o.getPropertyCSSValue("margin-top").getCssValueType());
assertEquals("0 cm", o.getPropertyCSSValue("margin-top").toString());
assertEquals("0 cm", o.getPropertyCSSValue("margin-top").getCssText());
assertEquals(CSSValue.CSS_VALUE_LIST, o.getPropertyCSSValue("margin-top").getCssValueType());
}
}
Big advantage of CSSParser is that it is currently in Maven. So if you look for something rather simple and straightforwardly usable CSSParser seems to be good option.
Notes: it does automatic conversion for colors from hex format to rgb() format, but provides no help with sizes with units, it sees them as list of values! Not so good.
