Java Map 和 Object 互转

🏷️ Java

使用 org.apache.commons.beanutils 进行转换

/**
 * 使用 org.apache.commons.beanutils 进行转换
 */
class A {
    public static Object mapToObject(Map<String, Object> map, Class<?> beanClass) throws Exception {
        if (map == null)
            return null;

        Object obj = beanClass.newInstance();

        org.apache.commons.beanutils.BeanUtils.populate(obj, map);

        return obj;
    }

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

        return new org.apache.commons.beanutils.BeanMap(obj);
    }
}

使用 Introspector 进行转换

/**
 * 使用 Introspector 进行转换
 */
class B {
    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;
    }
}

使用 reflect 进行转换

/**
 * 使用 reflect 进行转换
 */
class C {
    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;
    }
}

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原文：http://blog.csdn.net/wzygis/article/details/48105571

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