2、当isAccessible()的结果是false时不允许通过反射访问private变量。

package com.yung.ppapi.util;



import java.beans.BeanInfo;

import java.beans.Introspector;

import java.beans.PropertyDescriptor;

import java.lang.reflect.Field;

import java.lang.reflect.Method;

import java.lang.reflect.Modifier;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;



import org.apache.commons.beanutils.BeanMap;

import org.springframework.beans.BeanUtils;



import com.yung.ppapi.integration.dto.YCPFExpressDTO;



/**

 * 

 * @author lisheng4

 *

 */

public class BeanUtil {


    public static  T clone(Object source, Class type) {

        try {

        	if (source == null) {

        		return null;

        	}

            T target = type.newInstance();

            BeanUtils.copyProperties(source, target);

            return target;

        } catch (Exception e) {

        	e.printStackTrace();

            return null;

        } 

    } 

    public static  T clone(Object source, Class type, String... ignoreProperties) {

        try {

        	if (source == null) {

        		return null;

        	}

            T target = type.newInstance();

            BeanUtils.copyProperties(source, target, ignoreProperties);

            return target;

        } catch (Exception e) {

        	e.printStackTrace();

            return null;

        } 

    } 

/**
 * 利用反射实现
 * @param map
 * @param beanClass
 * @return
 * @throws Exception
 */
public static Object mapToObject(Map 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;
		}
		
		boolean accessFlag = field.isAccessible();
		field.setAccessible(true);// 允许通过反射访问该字段
		field.set(obj, map.get(field.getName()));
		field.setAccessible(accessFlag);
	}


	return obj;
}

/**
 * 利用反射实现
 * 
空属性不转换
 * 
超过10万条数据不建议使用
 * @param obj
 * @return
 * @throws Exception
 */
public static Map objectToMap(Object obj) throws Exception {


	if (obj == null) {
		return null;
	}


	Map map = new HashMap();
	Field[] fields = obj.getClass().getDeclaredFields();
	for (int i = 0, len = fields.length; i < len; i++) {
		String varName = fields[i].getName();
		boolean accessFlag = fields[i].isAccessible();
		fields[i].setAccessible(true);// 允许通过反射访问该字段


		Object valueObj = fields[i].get(obj);
		if (valueObj != null) {
			map.put(varName, valueObj);
		}
		fields[i].setAccessible(accessFlag);
	}
	return map;
}

/**
 * 利用java.beans.Introspector实现
 * @param map
 * @param beanClass
 * @return
 * @throws Exception
 */
public static Object mapToObject2(Map 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;  
}    
 
/**
 * 利用java.beans.Introspector实现
 * @param obj
 * @return
 * @throws Exception
 */
public static Map objectToMap2(Object obj) throws Exception {    
    if(obj == null)  
        return null;      


    Map map = new HashMap();   


    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;  
} 

/**
 * 利用org.apache.commons.beanutils.BeanUtils实现
 * @param map
 * @param beanClass
 * @return
 * @throws Exception
 */
public static Object mapToObject3(Map map, Class beanClass) throws Exception {    
    if (map == null)  
        return null;  


    Object obj = beanClass.newInstance();  
    org.apache.commons.beanutils.BeanUtils.populate(obj, map);  
    return obj;  
}    
 
/**
 * 利用org.apache.commons.beanutils.BeanMap实现
 * @param obj
 * @return
 */
public static Map objectToMap3(Object obj) {  
    if(obj == null)  
        return null;   


    return new BeanMap(obj);  
} 




//	public static void main(String[] args) throws Exception {

//		List> mapList = new ArrayList>();

//		List> mapList2 = new ArrayList>();

//		List> mapList3 = new ArrayList>();

//		long t11 = System.currentTimeMillis();

//		for(int i=1;i<=100000;i++) {

//			mapList.add(objectToMap(new YCPFExpressDTO()));

//		}

//		long t12 = System.currentTimeMillis();

//		

//		long t21 = System.currentTimeMillis();

//		for(int i=1;i<10000;i++) {

//			mapList2.add((Map) objectToMap2(new YCPFExpressDTO()));

//		}

//		long t22 = System.currentTimeMillis();

//		

//		long t31 = System.currentTimeMillis();

//		for(int i=1;i<10000;i++) {

//			mapList3.add((Map) objectToMap3(new YCPFExpressDTO()));

//		}

//		long t32 = System.currentTimeMillis();

//		System.out.println(t12-t11);

//		System.out.println(t22-t21);

//		System.out.println(t32-t31);

//		//System.out.println(t32-t31);

//	}



}

参考文章：https://www.cnblogs.com/XuYiHe/p/6871799.html

参考文章：https://blog.csdn.net/o_nianchenzi_o/article/details/78022416