java – 递归BeanUtils.describe()

Map<String,String> beanMap = BeanUtils.recursiveDescribe(customer);

一些警告.

>我不知道如何在集合中如何使用BeanUtils格式的属性,所以我用“attribute [index]”去了.
>我不知道如何在地图中格式化属性,所以我用“属性[key]”.
>对于名称冲突,优先级是这样的：第一个属性从超级类的字段,然后是类,然后从getter方法加载.
>我没有分析这种方法的性能.如果对象中包含大量集合的对象也包含集合,那么可能会有一些问题.
>这是阿尔法的代码,并不是无法免费的.
>我假设你有最新版本的commons beanutils

此外,fyi,这大概取自于我一直在工作的一个项目,亲切地,java in jails,所以你可以下载它,然后运行：

Map<String,String[]> beanMap = new SimpleMapper().toMap(customer);

虽然,你会注意到它返回一个String [],而不是String,这可能无法满足你的需要.无论如何,下面的代码应该工作,所以有它！

public class BeanUtils {
    public static Map<String,String> recursiveDescribe(Object object) {
        Set cache = new HashSet();
        return recursiveDescribe(object,null,cache);
    }

    private static Map<String,String> recursiveDescribe(Object object,String prefix,Set cache) {
        if (object == null || cache.contains(object)) return Collections.EMPTY_MAP;
        cache.add(object);
        prefix = (prefix != null) ? prefix + "." : "";

        Map<String,String> beanMap = new TreeMap<String,String>();

        Map<String,Object> properties = getProperties(object);
        for (String property : properties.keySet()) {
            Object value = properties.get(property);
            try {
                if (value == null) {
                    //ignore nulls
                } else if (Collection.class.isAssignableFrom(value.getClass())) {
                    beanMap.putAll(convertAll((Collection) value,prefix + property,cache));
                } else if (value.getClass().isArray()) {
                    beanMap.putAll(convertAll(Arrays.asList((Object[]) value),cache));
                } else if (Map.class.isAssignableFrom(value.getClass())) {
                    beanMap.putAll(convertMap((Map) value,cache));
                } else {
                    beanMap.putAll(convertObject(value,cache));
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return beanMap;
    }

    private static Map<String,Object> getProperties(Object object) {
        Map<String,Object> propertyMap = getFields(object);
        //getters take precedence in case of any name collisions
        propertyMap.putAll(getGetterMethods(object));
        return propertyMap;
    }

    private static Map<String,Object> getGetterMethods(Object object) {
        Map<String,Object> result = new HashMap<String,Object>();
        BeanInfo info;
        try {
            info = Introspector.getBeanInfo(object.getClass());
            for (PropertyDescriptor pd : info.getPropertyDescriptors()) {
                Method reader = pd.getReadMethod();
                if (reader != null) {
                    String name = pd.getName();
                    if (!"class".equals(name)) {
                        try {
                            Object value = reader.invoke(object);
                            result.put(name,value);
                        } catch (Exception e) {
                            //you can choose to do something here
                        }
                    }
                }
            }
        } catch (IntrospectionException e) {
            //you can choose to do something here
        } finally {
            return result;
        }

    }

    private static Map<String,Object> getFields(Object object) {
        return getFields(object,object.getClass());
    }

    private static Map<String,Object> getFields(Object object,Class<?> classType) {
        Map<String,Object>();

        Class superClass = classType.getSuperclass();
        if (superClass != null) result.putAll(getFields(object,superClass));

        //get public fields only
        Field[] fields = classType.getFields();
        for (Field field : fields) {
            try {
                result.put(field.getName(),field.get(object));
            } catch (IllegalAccessException e) {
                //you can choose to do something here
            }
        }
        return result;
    }

    private static Map<String,String> convertAll(Collection<Object> values,String key,Set cache) {
        Map<String,String> valuesMap = new HashMap<String,String>();
        Object[] valArray = values.toArray();
        for (int i = 0; i < valArray.length; i++) {
            Object value = valArray[i];
            if (value != null) valuesMap.putAll(convertObject(value,key + "[" + i + "]",cache));
        }
        return valuesMap;
    }

    private static Map<String,String> convertMap(Map<Object,Object> values,String>();
        for (Object thisKey : values.keySet()) {
            Object value = values.get(thisKey);
            if (value != null) valuesMap.putAll(convertObject(value,key + "[" + thisKey + "]",cache));
        }
        return valuesMap;
    }

    private static ConvertUtilsBean converter = BeanUtilsBean.getInstance().getConvertUtils();

    private static Map<String,String> convertObject(Object value,Set cache) {
        //if this type has a registered converted,then get the string and return
        if (converter.lookup(value.getClass()) != null) {
            String stringValue = converter.convert(value);
            Map<String,String> valueMap = new HashMap<String,String>();
            valueMap.put(key,stringValue);
            return valueMap;
        } else {
            //otherwise,treat it as a nested bean that needs to be described itself
            return recursiveDescribe(value,key,cache);
        }
    }
}