Java 類動態添加屬性字段的操作

public class DynamicBean {
 private Object object = null; // 動態生成的類 
 private BeanMap beanMap = null; // 存放屬性名稱以及屬性的類型 
 public DynamicBean() {
  super();
 }
 
 public DynamicBean(Map propertyMap) {
  this.object = generateBean(propertyMap);
  this.beanMap = BeanMap.create(this.object);
 }
 
 /**
  * @param propertyMap
  * @return
  */
 private Object generateBean(Map propertyMap) {
  BeanGenerator generator = new BeanGenerator();
  Set keySet = propertyMap.keySet();
  for (Iterator<String> i = keySet.iterator(); i.hasNext();) {
   String key = (String) i.next();
   generator.addProperty(key, (Class) propertyMap.get(key));
  }
  return generator.create();
 }
 
 /**
  * ��bean���Ը�ֵ
  * @param property ������
  * @param value ֵ
  */
 public void setValue(Object property, Object value) {
  beanMap.put(property, value);
 }
 
 /**
  * ͨ���������õ�����ֵ
  * @param property ������
  * @return ֵ
  */
 public Object getValue(String property) {
  return beanMap.get(property);
 }
 
 /**
  * 返回新生成的對象
  * @return
  */
 public Object getObject() {
  return this.object;
 }
}

/**
*參數說明：
* object ： 查詢結果數組中對象。
* moneyMap ： 為對象對應所有月份數據集合
* 解釋：已經查詢出一組賬單對象集合List<Bill> , 而moneyMap為對象中的一個屬性 
* Map<String,Bigdecimal>， 存放瞭月份及金額
*/
private Object dynamicClass(Object object, Map<String, BigDecimal> moneyMap) throws Exception {
  // 字段 - 值 集合
  HashMap<String, Object> returnMap = new HashMap<String, Object>();
  // 字段 - 字段類型 集合
  HashMap<String, Object> typeMap = new HashMap<String, Object>();
  // 獲取傳入類
  Class<? extends Object> type = object.getClass();
  BeanInfo beanInfo = Introspector.getBeanInfo(type);
  PropertyDescriptor[] propertyDescriptors = beanInfo.getPropertyDescriptors();
  // 獲取對象中已存在的數據
  for (int i = 0; i < propertyDescriptors.length; i++) {
   PropertyDescriptor descriptor = propertyDescriptors[i];
   String propertyName = descriptor.getName();
   if (!propertyName.equals("class") && !propertyName.equals("monthMap")) {
    Method readMethod = descriptor.getReadMethod();
    Object result = readMethod.invoke(object, new Object[0]);
    if (result != null) {
     returnMap.put(propertyName, result);
    } else {
     String propertyType = descriptor.getPropertyType().toString();
     if (propertyType.contains("java.math.BigDecimal")) {
      returnMap.put(propertyName, new BigDecimal(0));
     } else {
      returnMap.put(propertyName, "");
     }
    }
    typeMap.put(propertyName, descriptor.getPropertyType());
   }
  }
  // 獲取月份數據， 變為字段屬性
  Set<String> monthKeys = moneyMap.keySet();
  for (Iterator<String> it = monthKeys.iterator(); it.hasNext();) {
   String key = (String) it.next();
   // 字段類型
   typeMap.put(key, Class.forName("java.math.BigDecimal"));
   // 字段對應值
   returnMap.put(key, moneyMap.get(key));
  }
  // map轉換成實體對象
  DynamicBean bean = new DynamicBean(typeMap);
  // 賦值
  Set<String> keys = typeMap.keySet();
  for (Iterator<String> it = keys.iterator(); it.hasNext();) {
   String key = (String) it.next();
   bean.setValue(key, returnMap.get(key));
  }
  Object obj = bean.getObject();
  return obj;
 }

compile("commons-beanutils:commons-beanutils:1.9.3")
compile("cglib:cglib-nodep:3.2.4")

import java.util.Map; 
import net.sf.cglib.beans.BeanGenerator;
import net.sf.cglib.beans.BeanMap; 
public class DynamicBean {
 
 /**
  * 目標對象
  */
 private Object target;
 /**
  * 屬性集合
  */
 private BeanMap beanMap;
 
 public DynamicBean(Class superclass, Map<String, Class> propertyMap){
  this.target = generateBean(superclass, propertyMap);
  this.beanMap = BeanMap.create(this.target);
 }
 
 /**
  * bean 添加屬性和值
  *
  * @param property
  * @param value
  */
 public void setValue(String property, Object value) {
  beanMap.put(property, value);
 }
 
 /**
  * 獲取屬性值
  *
  * @param property
  * @return
  */
 public Object getValue(String property) {
  return beanMap.get(property);
 }
 
 /**
  * 獲取對象
  *
  * @return
  */
 public Object getTarget() {
  return this.target;
 }
 
 /**
  * 根據屬性生成對象
  *
  * @param superclass
  * @param propertyMap
  * @return
  */
 private Object generateBean(Class superclass, Map<String, Class> propertyMap) {
  BeanGenerator generator = new BeanGenerator();
  if (null != superclass) {
   generator.setSuperclass(superclass);
  }
  BeanGenerator.addProperties(generator, propertyMap);
  return generator.create();
 }
}

import java.beans.PropertyDescriptor;
import java.util.HashMap;
import java.util.Map; 
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger; 
import org.apache.commons.beanutils.PropertyUtilsBean; 
import com.sunxung.factoring.entity.DynamicBean;
import com.sunxung.factoring.entity.attendanceManagement.AttendanceVo;
 
/**
 * @className:ReflectUtil
 * @description:動態生成類的屬性、並且賦值
 * @date:2018年4月3日 下午2:33:10
 */
public class ReflectUtil {
 
 static Logger logger = LogManager.getLogger(ReflectUtil.class);
 
 @SuppressWarnings("rawtypes")
 public static Object getTarget(Object dest, Map<String, Object> addProperties) {
  PropertyUtilsBean propertyUtilsBean = new PropertyUtilsBean();
  PropertyDescriptor[] descriptors = propertyUtilsBean.getPropertyDescriptors(dest);
  Map<String, Class> propertyMap = new HashMap<>();
  for (PropertyDescriptor d : descriptors) {
   if (!"class".equalsIgnoreCase(d.getName())) {
    propertyMap.put(d.getName(), d.getPropertyType());
   }
  }
  // add extra properties
  addProperties.forEach((k, v) -> propertyMap.put(k, v.getClass()));
  // new dynamic bean
  DynamicBean dynamicBean = new DynamicBean(dest.getClass(), propertyMap);
  // add old value
  propertyMap.forEach((k, v) -> {
   try {
    // filter extra properties
    if (!addProperties.containsKey(k)) {
     dynamicBean.setValue(k, propertyUtilsBean.getNestedProperty(dest, k));
    }
   } catch (Exception e) {
    logger.error(e.getMessage(), e);
   }
  });
  // add extra value
  addProperties.forEach((k, v) -> {
   try {
    dynamicBean.setValue(k, v);
   } catch (Exception e) {
    logger.error(e.getMessage(), e);
   }
  });
  Object target = dynamicBean.getTarget();
  return target;
 }
 
 public static void main(String[] args) {
  AttendanceVo entity = new AttendanceVo();
  Map<String, Object> addProperties = new HashMap<>();
  addProperties.put("day31", "你好");
  AttendanceVo newVo = (AttendanceVo) getTarget(entity, addProperties);
  System.out.println(newVo.getDay0());
 }
}

private AttendanceVo autoDetailNew(SearchAttendanceVo search, AttendanceVo att) {
  search.setDingdingUserId(att.getDingdingUserId());
  List<Attendance> detailList = attendanceMapper.findDetailList(search);
  Map<String, Object> addProperties = new HashMap<>();
  for (Attendance attendance : detailList) {
   addProperties.put("day" + DateUtil.getDayStringFormatYMD(attendance.getAttendanceDate()),
     attendance.getRemark());
  }
  AttendanceVo newVo = (AttendanceVo) ReflectUtil.getTarget(att, addProperties);
  return newVo;
 }