java.lang.AbstractMethodError: javax.xml.transform.TransformerFactory.setFeature(Ljava/lang/String；Z

java.lang.AbstractMethodError: javax.xml.transform.TransformerFactory.setFeature(Ljava/lang/String;Z)V

 private static String transForm(String xml, InputStream xsltStream) {
    	if(xml == null || "".equals(xml)) {
    		return null;
    	}
        ByteArrayOutputStream retXml = new ByteArrayOutputStream();
        try {
            InputStream xmlStream = new ByteArrayInputStream(xml.getBytes("GBK"));
            TransformerFactory factory = TransformerFactory.newInstance();
            factory.setFeature(XMLConstants.FEATURE_SECURE_PROCESSING, true);
            Source xslSource = new StreamSource(xsltStream);
            Transformer transformer = factory.newTransformer(xslSource);
            transformer.setOutputProperty(OutputKeys.INDENT, "yes");
            transformer.setOutputProperty(javax.xml.transform.OutputKeys.ENCODING, "UTF-8");
            transformer.transform(new StreamSource(xmlStream), new StreamResult(retXml));
            return retXml.toString("UTF-8");
        } catch (UnsupportedEncodingException | TransformerException e) {
            e.printStackTrace();
        }
        return null;
    }

 factory.setFeature(XMLConstants.FEATURE_SECURE_PROCESSING, true); 的时候报错

问题原因：TransformerFactory里面是抽象方法，当子类有多个的时候就分不清该调用哪个，简单来说就是找子类抽象实现的时候发生冲突

解决方法一：

ctrl+t 发现实现类有两个

然后打出依赖树，

过滤掉就好了

<dependency>
            <groupId>comxxx</groupId>
            <artifactId>xxx</artifactId>
            <version>1.1.31</version>
            <exclusions>
                <exclusion>
                    <groupId>xalan</groupId>
                    <artifactId>xalan</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

解决方法二：前面设置好他的实现类，里面会根据这个实现类去创建实例

System.setProperty("javax.xml.transform.TransformerFactory", "com.sun.org.apache.xalan.internal.xsltc.trax.TransformerFactoryImpl");

 TransformerFactory factory = TransformerFactory.newInstance();