8. Object转Map，Map转Object

法一：使用reflect进行转换

public static Object mapToObject(Map<String, Object> map, Class<?> beanClass) throws Exception {
    if (map == null)
        return null;    
    Object obj = beanClass.newInstance();
    Field[] fields = obj.getClass().getDeclaredFields();
    for (Field field : fields) {
        int mod = field.getModifiers();
        if(Modifier.isStatic(mod) || Modifier.isFinal(mod)){
            continue;
        }
        field.setAccessible(true);
        field.set(obj, map.get(field.getName()));
    }   
    return obj;
}    

public static Map<String, Object> objectToMap(Object obj) throws Exception {
    if(obj == null){
        return null;
    }   

    Map<String, Object> map = new HashMap<String, Object>();    

    Field[] declaredFields = obj.getClass().getDeclaredFields();
    for (Field field : declaredFields) {
        field.setAccessible(true);
        map.put(field.getName(), field.get(obj));
    }    

    return map;
}   

法二：使用Introspector进行转换

public static Object mapToObject(Map<String, Object> map, Class<?> beanClass) throws Exception {
    if (map == null)
        return null;    

    Object obj = beanClass.newInstance();  

    BeanInfo beanInfo = Introspector.getBeanInfo(obj.getClass());
    PropertyDescriptor[] propertyDescriptors = beanInfo.getPropertyDescriptors();
    for (PropertyDescriptor property : propertyDescriptors) {
        Method setter = property.getWriteMethod();
        if (setter != null) {
            setter.invoke(obj, map.get(property.getName()));
        }
    }  

    return obj;
}    

public static Map<String, Object> objectToMap(Object obj) throws Exception {
    if(obj == null)
        return null;      

    Map<String, Object> map = new HashMap<String, Object>();   

    BeanInfo beanInfo = Introspector.getBeanInfo(obj.getClass());
    PropertyDescriptor[] propertyDescriptors = beanInfo.getPropertyDescriptors();
    for (PropertyDescriptor property : propertyDescriptors) {
        String key = property.getName();
        if (key.compareToIgnoreCase("class") == 0) {
            continue;
        }
        Method getter = property.getReadMethod();
        Object value = getter!=null ? getter.invoke(obj) : null;
        map.put(key, value);
    }    

    return map;
}