Java Several Methods Of Converting Between Map and Object

**
 * Convert using com.fasterxml.jackson.databind.ObjectMapper
 */
class A {

    public static Object mapToObject (Map&lt;String, Object&gt; map, Class&lt;?&gt; beanClass) throws Exception {
        if (map == null) {
            return null;
        }

        ObjectMapper objectMapper = new ObjectMapper();
        Object obj = objectMapper.convertValue(map, beanClass);

        return obj;
    }

    public static Map&lt;?, ?&gt; objectToMap (Object obj) {
        if (obj == null) {
            return null;
        }

        ObjectMapper objectMapper = new ObjectMapper();
        Map&lt;?, ?&gt; mappedObject = objectMapper.convertValue(obj, Map.class);

        return mappedObject;
    }
}

/**
 * Use org.apache.commons.beanutils for conversion
 */
class B {

    public static Object mapToObject(Map&lt;String, Object&gt; map, Class&lt;?&gt; 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&lt;?, ?&gt; objectToMap(Object obj) {
        if (obj == null) {
            return null;
        }

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

}

/**
 * Convert using Introspector
 */
class C {

    public static Object mapToObject(Map&lt;String, Object&gt; map, Class&lt;?&gt; beanClass) throws Exception {
        if (map == null) {
            return null;
        }

        Object obj = beanClass.newInstance();

        BeanInfo beanInfo = Introspector.getBeanInfo(obj.getClass());
        PropertyDescriptor&#91;] 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&lt;String, Object&gt; objectToMap(Object obj) throws Exception {
        if (obj == null) {
            return null;
        }

        Map&lt;String, Object&gt; map = new HashMap&lt;String, Object&gt;();

        BeanInfo beanInfo = Introspector.getBeanInfo(obj.getClass());
        PropertyDescriptor&#91;] 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;
    }

}

/**
 * use reflect to convert
 */
class D {

    public static Object mapToObject(Map&lt;String, Object&gt; map, Class&lt;?&gt; beanClass) throws Exception {
        if (map == null) {
            return null;
        }

        Object obj = beanClass.newInstance();

        Field&#91;] 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&lt;String, Object&gt; objectToMap(Object obj) throws Exception {
        if (obj == null) {
            return null;
        }

        Map&lt;String, Object&gt; map = new HashMap&lt;String, Object&gt;();

        Field&#91;] declaredFields = obj.getClass().getDeclaredFields();
        for (Field field : declaredFields) {
            field.setAccessible(true);
            map.put(field.getName(), field.get(obj));
        }

        return map;
    }
}

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* Convert using com.fasterxml.jackson.databind.ObjectMapper

class A {

public static Object mapToObject (Map<String, Object> map, Class<?> beanClass) throws Exception {

if (map == null) {

return null;

}

ObjectMapper objectMapper = new ObjectMapper();

Object obj = objectMapper.convertValue(map, beanClass);

return obj;

}

public static Map<?, ?> objectToMap (Object obj) {

if (obj == null) {

return null;

}

ObjectMapper objectMapper = new ObjectMapper();

Map<?, ?> mappedObject = objectMapper.convertValue(obj, Map.class);

return mappedObject;

}

/**

* Use org.apache.commons.beanutils for conversion

class B {

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);

}

/**

* Convert using Introspector

class C {

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;

}

/**

* use reflect to convert

class D {

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;

}