java操作mongodb时，对象bean和DBObject相互转换的方法

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 {  
  
  /** 
   * 把实体bean对象转换成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();  
    // 获取对象对应类中的所有属性域  
    Field[] fields = bean.getClass().getDeclaredFields();  
    for (Field field : fields) {  
      // 获取属性名  
      String varName = field.getName();  
      // 修改访问控制权限  
      boolean accessFlag = field.isAccessible();  
      if (!accessFlag) {  
        field.setAccessible(true);  
      }  
      Object param = field.get(bean);  
      if (param == null) {  
        continue;  
      } else if (param instanceof Integer) {//判断变量的类型  
        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);  
      }  
      // 恢复访问控制权限  
      field.setAccessible(accessFlag);  
    }  
    return dbObject;  
  }  
  
  /** 
   * 把DBObject转换成bean对象 
   * @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;  
  }  
} 

出自：http://iqbon.iteye.com/blog/1756118