版权声明:本文为博主原创文章,未经博主允许不得转载。 https://blog.csdn.net/u011067966/article/details/80780741
public class ListToListOrMapUtils {
public static List list2list(List list, String fieldName4Key,Class<?> c) {
/**
*@param
* list:输入list
* fieldName4Key:字段名
* c:类
*/
List<Object> objectArrayList = new ArrayList<>();
if (list != null) {
try {
PropertyDescriptor propDesc = new PropertyDescriptor(fieldName4Key, c);
Method methodGetKey = propDesc.getReadMethod();
for (int i = 0; i < list.size(); i++) {
Object o = list.get(i);
Object invoke = methodGetKey.invoke(o);
if(null != invoke){
objectArrayList.add(invoke);
}
}
} catch (Exception e) {
e.printStackTrace();
throw new IllegalArgumentException("field can't match the key!");
}
}
return objectArrayList;
}
public static <K, V> Map<K, V> list2Map(List<V> list, String fieldName4Key,Class<V> c) {
Map<K, V> map = new HashMap<K, V>();
if (list != null) {
try {
PropertyDescriptor propDesc = new PropertyDescriptor(fieldName4Key, c);
Method methodGetKey = propDesc.getReadMethod();
for (int i = 0; i < list.size(); i++) {
V value = list.get(i);
@SuppressWarnings("unchecked")
K key = (K) methodGetKey.invoke(value);
map.put(key, value);
}
} catch (Exception e) {
throw new IllegalArgumentException("field can't match the key!");
}
}
return map;
}
用法如下:
Map<Object, User> userMap = ListToListOrMapUtils.list2Map(userList, "id", User.class);
List uidList = ListToListOrMapUtils.list2list(userList, "uid", User.class);