Java代码实现Map和Object互转及Map和Json互转

 /** * 使用org.apache.commons.beanutils进行转换 */ class A { public static Object mapToObject(Map 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 */ class B { public static Object mapToObject(Map 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 objectToMap(Object obj) throws Exception { if(obj == null) return null; Map map = new HashMap(); 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 */ class C { public static Object mapToObject(Map 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 objectToMap(Object obj) throws Exception { if(obj == null){ return null; } Map map = new HashMap(); Field[] declaredFields = obj.getClass().getDeclaredFields(); for (Field field : declaredFields) { field.setAccessible(true); map.put(field.getName(), field.get(obj)); } return map; } 
} 
 
from：http://www.open-open.com/code/view/1423280939826

 Map map = new HashMap(); map.put("method","json"); map.put("param",null); map.put("time","2015-01-23 10:54:55"); ObjectMapper mapper = new ObjectMapper(); mapper.writeValueAsString(map); 

 public static void readJson2Map(String json) { ObjectMapper objectMapper = new ObjectMapper(); try { //将json字符串转成map结合解析出来，并打印(这里以解析成map为例) Map> maps = objectMapper.readValue( json, Map.class); System.out.println(maps.size()); Set key = maps.keySet(); Iterator iter = key.iterator(); while (iter.hasNext()) { String field = iter.next(); System.out.println(field + ":" + maps.get(field)); } } catch (JsonParseException e) { e.printStackTrace(); } catch (JsonMappingException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } readJson2Map(json);