Java CSS 解析器

要求

目标是使用 Java CSS 解析器获取 HTML 文档中特定元素的 CSS 样式。

解决方案

CSSParser

推荐一个选项是 CSSParser，一个提供错误反馈的强大解析器。下面是它的用法示例：

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 {

    public static void main(String[] args) {

        CSSParserTest 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 {

            InputStream stream = oParser.getClass().getResourceAsStream(cssfile);

            out = new FileOutputStream("log.txt");

            if (out != null) {

                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();
            CSSStyleSheet stylesheet = parser.parseStyleSheet(source, null, null);

            CSSRuleList ruleList = stylesheet.getCssRules();

            ps.println("Number of rules: "   ruleList.getLength());

            for (int i = 0; i 
此示例演示如何解析 CSS 文件并提取每个选择器和属性的样式信息，包括它们的值和优先级。