解决使用Struts2的s:textfield标签出现Unable to find setter method for attribute: style的问题

把项目中的struts2从2.3.1.2升级到2.3.20，跑起来之后出现一个这样的问题：

org.apache.jasper.JasperException: /pages/login.jsp (line: 103, column: 7) Unable to find setter method for attribute: style

错误消息很明显：没有style的setter方法，但是很诡异，jsp中哪有什么setter方法，定位到代码一看，是s:textfield中的style属性：

<s:textfield label="用户ID" name="model.userid" id="userid" required="true" class="{character:true}" style="width:220px; height:30px; margin-left:10px;" />

谷歌下，发现是Struts2 2.3.20的一个bug，org.apache.struts2.views.jsp.ui.AbstractUITagBeanInfo中没有对style属性进行解析处理：

public class AbstractUITagBeanInfo extends SimpleBeanInfo {

    private static final Logger LOG = LoggerFactory.getLogger(AbstractUITagBeanInfo.class);

    @Override
    public PropertyDescriptor[] getPropertyDescriptors() {
        try {
            List<PropertyDescriptor> descriptors = new ArrayList<PropertyDescriptor>();

            // Add the tricky one first
            Method setter = AbstractUITag.class.getMethod("setCssClass", String.class);
            descriptors.add(new PropertyDescriptor("class", null, setter));
            descriptors.add(new PropertyDescriptor("cssClass", null, setter));

            for (Field field : AbstractUITag.class.getDeclaredFields()) {
                String fieldName = field.getName();
                if (!"dynamicAttributes".equals(fieldName)) {
                    String setterName = "set" + fieldName.substring(0, 1).toUpperCase() + fieldName.substring(1);
                    setter = AbstractUITag.class.getMethod(setterName, String.class);
                    descriptors.add(new PropertyDescriptor(fieldName, null, setter));
                }
            }

            PropertyDescriptor[] array = new PropertyDescriptor[descriptors.size()];
            return descriptors.toArray(array);
        } catch (Exception e) {
            // This is crazy talk, we're only doing things that should always succeed
            LOG.fatal("Could not construct bean info for AbstractUITag. This is very bad.", e);
            return null;
        }
    }

}

目前已经在2.3.21中已经修复了：

public class AbstractUITagBeanInfo extends SimpleBeanInfo {

    private static final Logger LOG = LoggerFactory.getLogger(AbstractUITagBeanInfo.class);

    @Override
    public PropertyDescriptor[] getPropertyDescriptors() {
        try {
            List<PropertyDescriptor> descriptors = new ArrayList<PropertyDescriptor>();

            // Add the tricky one first
            Method classSetter = AbstractUITag.class.getMethod("setCssClass", String.class);
            Method styleSetter = AbstractUITag.class.getMethod("setCssStyle", String.class);

            descriptors.add(new PropertyDescriptor("class", null, classSetter));
            descriptors.add(new PropertyDescriptor("cssClass", null, classSetter));

            descriptors.add(new PropertyDescriptor("style", null, styleSetter));
            descriptors.add(new PropertyDescriptor("cssStyle", null, styleSetter));

            for (Field field : AbstractUITag.class.getDeclaredFields()) {
                String fieldName = field.getName();
                if (!"dynamicAttributes".equals(fieldName)) {
                    String setterName = "set" + fieldName.substring(0, 1).toUpperCase() + fieldName.substring(1);
                    Method setter = AbstractUITag.class.getMethod(setterName, String.class);
                    descriptors.add(new PropertyDescriptor(fieldName, null, setter));
                }
            }

            PropertyDescriptor[] array = new PropertyDescriptor[descriptors.size()];
            return descriptors.toArray(array);
        } catch (Exception e) {
            // This is crazy talk, we're only doing things that should always succeed
            LOG.fatal("Could not construct bean info for AbstractUITag. This is very bad.", e);
            return null;
        }
    }

}

jira：https://fisheye6.atlassian.com/browse/struts/core/src/main/java/org/apache/struts2/views/jsp/ui/AbstractUITagBeanInfo.java?r1=587e3a41b1d306eb246aa39d71dce469f4e50e9d&r2=4964b74797971751bedad0ba0982f53ef0934a2c