java - Apache Commons BeanUtilsBean - 从 describe() 中排除属性

Question

我正在使用 BeanutilsBean.describe() 方法来获取数据以进行审计跟踪。它工作得很好 - 这不是问题!

然而，有些属性不需要审核。这些被记录为列表中的字符串。因此，例如，如果您有一个属性 DomainObject.myValue，则该列表将包含 "myValue"，以便调用 DomainObject.getMyValue()< 的结果 不包含在审计跟踪中。

目前，代码从 BeanutilsBean.describe() 获取所有属性，然后遍历它们以丢弃不需要的属性。

我想要做的是使用要排除的属性名称列表配置 BeanUtilsBean 实例，这样它就永远不会调用这些方法。因此，在我的示例中，根本不会调用 DomainObject.getMyValue()。

通过查看 API 或代码，我无法确定这是否可行。

Answer 1

这是我用来解决这个问题的代码。

它是 BeanUtilsBean.describe() 的一个略微修改的副本，它不调用排除的属性 getter；这是 ach's answer 中的“自己动手”选项(第一个选项已经在实时代码中使用了几年，但它从未适合我!)。

import java.beans.PropertyDescriptor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;

import org.apache.commons.beanutils.BeanUtilsBean;
import org.apache.commons.beanutils.DynaBean;
import org.apache.commons.beanutils.DynaProperty;
import org.apache.commons.beanutils.MethodUtils;

public class BeanUtilsBeanExtensions {

    private static final BeanUtilsBean BEAN_UTILS_BEAN = BeanUtilsBean
                    .getInstance();

    public BeanUtilsBeanExtensions() {
    }

    /**
     * Extends BeanUtilsBean.describe() so that it can be given a list of
     * attributes to exclude. This avoids calling methods which might derive
     * data which don't happen to be populated when the describe() call is made
     * (and therefore could throw exceptions) as well as being more efficient
     * than describing everything then discarding attributes which aren't
     * required.
     *
     * @param bean
     *            See BeanUtilsBean.describe()
     * @param excludedAttributeNames
     *            the attribute names which should not be described.
     * @return See BeanUtilsBean.describe()
     */
    public Map<String, String> describe(Object bean,
                    Set<String> excludedAttributeNames)
                    throws IllegalAccessException,
                    InvocationTargetException, NoSuchMethodException {

        // This method is mostly just a copy/paste from BeanUtilsBean.describe()
        // The only changes are:
        // - Removal of reference to the (private) logger
        // - Addition of Reference to a BeanUtilsBean instance
        // - Addition of calls to excludedAttributeNames.contains(name)
        // - Use of generics on the Collections
        // - Calling of a copy of PropertyUtilsBean.getReadMethod()

        if (bean == null) {
            return (new java.util.HashMap<String, String>());
        }

        Map<String, String> description = new HashMap<String, String>();
        if (bean instanceof DynaBean) {
            DynaProperty[] descriptors = ((DynaBean) bean).getDynaClass()
                            .getDynaProperties();
            for (int i = 0; i < descriptors.length; i++) {
                String name = descriptors[i].getName();
                if (!excludedAttributeNames.contains(name)) {
                    description.put(name,
                                    BEAN_UTILS_BEAN.getProperty(bean, name));
                }
            }
        }
        else {
            PropertyDescriptor[] descriptors = BEAN_UTILS_BEAN
                            .getPropertyUtils().getPropertyDescriptors(bean);
            Class<? extends Object> clazz = bean.getClass();
            for (int i = 0; i < descriptors.length; i++) {
                String name = descriptors[i].getName();
                if (!excludedAttributeNames.contains(name)
                                && getReadMethod(clazz, descriptors[i]) != null) {
                    description.put(name,
                                    BEAN_UTILS_BEAN.getProperty(bean, name));
                }
            }
        }
        return description;
    }

    /*
     * Copy of PropertyUtilsBean.getReadMethod() since that is package-private.
     */
    private Method getReadMethod(Class<? extends Object> clazz,
                    PropertyDescriptor descriptor) {
        return MethodUtils.getAccessibleMethod(clazz,
                        descriptor.getReadMethod());
    }

}