Java code realizes mutual conversion between Map and Object and between Map and Json

Let me first introduce to you the code for converting map and object to each other.

The specific code is as shown:

/**
* 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
*/
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
*/
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;
}
<p>} </p><p>
</p><p>from：http://www.open-open.com/code/view/1423280939826</p>

The following will introduce the mutual conversion between Map and json

The first paragraph Code

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

The second code

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<String, Map<String, Object>> maps = objectMapper.readValue(
json, Map.class);
System.out.println(maps.size());
Set<String> key = maps.keySet();
Iterator<String> 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);

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