When java operates on mongodb the method of recommends that objects bean and DBObject convert to each other

As follows:

package com.iqbon.spider.util; 
 
import java.lang.reflect.Field; 
import java.lang.reflect.InvocationTargetException; 
import java.util.Date; 
 
import org.apache.commons.beanutils.BeanUtils; 
 
import com.mongodb.BasicDBObject; 
import com.mongodb.DBObject; 
 
public class BeanUtil { 
 
 /** 
  *  The entity bean Object conversion to DBObject 
  * @param bean 
  * @return 
  * @throws IllegalArgumentException 
  * @throws IllegalAccessException 
  */ 
 public static <T> DBObject bean2DBObject(T bean) throws IllegalArgumentException, 
   IllegalAccessException { 
  if (bean == null) { 
   return null; 
  } 
  DBObject dbObject = new BasicDBObject(); 
  //  Gets all property fields in the corresponding class of the object  
  Field[] fields = bean.getClass().getDeclaredFields(); 
  for (Field field : fields) { 
   //  Get the property name  
   String varName = field.getName(); 
   //  Modify access control permissions  
   boolean accessFlag = field.isAccessible(); 
   if (!accessFlag) { 
    field.setAccessible(true); 
   } 
   Object param = field.get(bean); 
   if (param == null) { 
    continue; 
   } else if (param instanceof Integer) {// Determine the type of the variable  
    int value = ((Integer) param).intValue(); 
    dbObject.put(varName, value); 
   } else if (param instanceof String) { 
    String value = (String) param; 
    dbObject.put(varName, value); 
   } else if (param instanceof Double) { 
    double value = ((Double) param).doubleValue(); 
    dbObject.put(varName, value); 
   } else if (param instanceof Float) { 
    float value = ((Float) param).floatValue(); 
    dbObject.put(varName, value); 
   } else if (param instanceof Long) { 
    long value = ((Long) param).longValue(); 
    dbObject.put(varName, value); 
   } else if (param instanceof Boolean) { 
    boolean value = ((Boolean) param).booleanValue(); 
    dbObject.put(varName, value); 
   } else if (param instanceof Date) { 
    Date value = (Date) param; 
    dbObject.put(varName, value); 
   } 
   //  Restore access control permissions  
   field.setAccessible(accessFlag); 
  } 
  return dbObject; 
 } 
 
 /** 
  *  the DBObject Converted to bean object  
  * @param dbObject 
  * @param bean 
  * @return 
  * @throws IllegalAccessException 
  * @throws InvocationTargetException 
  * @throws NoSuchMethodException 
  */ 
 public static <T> T dbObject2Bean(DBObject dbObject, T bean) throws IllegalAccessException, 
   InvocationTargetException, NoSuchMethodException { 
  if (bean == null) { 
   return null; 
  } 
  Field[] fields = bean.getClass().getDeclaredFields(); 
  for (Field field : fields) { 
   String varName = field.getName(); 
   Object object = dbObject.get(varName); 
   if (object != null) { 
    BeanUtils.setProperty(bean, varName, object); 
   } 
  } 
  return bean; 
 } 
}