对象转map工具类BeanUtil

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1、

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> T clone(Object source, Class<T> 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> T clone(Object source, Class<T> 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<String, Object> 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
	 * <li>空属性不转换
	 * <li>超过10万条数据不建议使用
	 * @param obj
	 * @return
	 * @throws Exception
	 */
	public static Map<String, Object> objectToMap(Object obj) throws Exception {

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

		Map<String, Object> map = new HashMap<String, Object>();
		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<String, Object> 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<String, Object> objectToMap2(Object obj) throws Exception {    
	    if(obj == null)  
	        return null;      

	    Map<String, Object> map = new HashMap<String, Object>();   

	    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<String, Object> 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<Map<String,Object>> mapList = new ArrayList<Map<String,Object>>();
//		List<Map<String,Object>> mapList2 = new ArrayList<Map<String,Object>>();
//		List<Map<String,Object>> mapList3 = new ArrayList<Map<String,Object>>();
//		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<String, Object>) objectToMap2(new YCPFExpressDTO()));
//		}
//		long t22 = System.currentTimeMillis();
//		
//		long t31 = System.currentTimeMillis();
//		for(int i=1;i<10000;i++) {
//			mapList3.add((Map<String, Object>) 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

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