java 反射

package org.vanpull.frame.commons.page.util;

import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.Calendar;
import java.util.HashMap;
import java.util.Map;

import org.vanpull.demo.pojo.User;

/** *//**
 * 
 * <p>
 * Title:[Bean反射加强]
 * </p>
 * <p>
 * Description: [利用反射机制,处理Bean]
 * </p>
 * <p>
 * Copyright 2009 Huyvanpull Co., Ltd.
 * </p>
 * <p>
 * All right reserved.
 * </p>
 * 
 * @version 1.0
 * 
 * <p>
 * Created by [Huyvanpull] [Jul 6, 2009]
 * </p>
 * <p>
 * Midified by [修改人] [修改时间]
 * </p>
 * 
 */
public class BeanRelectUtil
{
    /** *//**
     * 
     * <p>
     * Description:[把Bean对象的属性和值映射成一个MAP]
     * </p>
     * <p>
     * Created by [Huyvanpull] [Jul 6, 2009]
     * </p>
     * <p>
     * Midified by [修改人] [修改时间]
     * </p>
     * 
     * @return
     */
    public Map<String, Object> bean2Map(Object bean)
    {
        Map<String, Object> fieldNVMap = new HashMap<String, Object>();
        /** *//** 如果bean参数的值为null,直接返回 */
        if (bean == null)
        {
            return fieldNVMap;
        }
        Class<?> claz = bean.getClass();
        /** *//** 得到bean的所有成员变量 */
        Field[] fileds = claz.getDeclaredFields();
        for (Field field : fileds)
        {
            String fieldName = field.getName();
            String getterMethodName = getGetterOrSetterName(fieldName, "get");
            Object filedValue = null;
            try
            {
                /** *//** 根据成员变量得到该变量的Getter方法 */
                Method method = claz.getMethod(getterMethodName);
                if (method != null)
                {
                    /** *//** 根据该成员变量的Getter方法得到该方法的值 */
                    filedValue = method.invoke(bean, new Object[0]);
                }
                fieldNVMap.put(fieldName, filedValue);
            }
            catch (Exception ex)
            {}
        }
        return fieldNVMap;
    }
    
    /** *//**
     * 
     * <p>
     * Description:[把Map中的键值对映射成对象的属性和值]
     * </p>
     * <p>
     * Created by [Huyvanpull] [Jul 6, 2009]
     * </p>
     * <p>
     * Midified by [修改人] [修改时间]
     * </p>
     * 
     * @param claz
     * @param fieldNVMap
     * @return
     */
    public Object map2Bean(Class<?> beanClaz, Map<String, Object> fieldNVMap)
    {
        Object object = null;
        /** *//** 防止claz不存不带参数的构造方法开始 ************ */
        try
        {
            object = beanClaz.newInstance();
        }
        catch (Exception ex)
        {
            return object;
        }
        /** *//** 防止claz不存不带参数的构造方法结束 ************ */
        
        Field[] fields = beanClaz.getDeclaredFields();
        for (Field field : fields)
        {
            String fieldName = field.getName();
            Object fieldValue = fieldNVMap.get(fieldName);
            /** *//** 参数类型是否相同,不同则进行下一轮循环 */
            if (fieldValue != null && fieldValue.getClass() != field.getType())
            {
                continue;
            }
            /** *//** 得到Setter方法 */
            String setterName = getGetterOrSetterName(fieldName, "set");
            try
            {
                Method method = beanClaz.getMethod(setterName, field.getType());
                if (method != null)
                {
                    Object[] params = new Object[1];
                    params[0] = fieldValue;
                    /** *//** 调用Setter方法,设置该对象的值 */
                    method.invoke(object, params);
                }
            }
            catch (Exception ex)
            {
                ex.printStackTrace();
            }
        }
        return object;
    }
    
    /** *//**
     * 
     * <p>
     * Description:[根据成员变量名,得到成员变量的Getter或Setter方法名]
     * </p>
     * <p>
     * Created by [Huyvanpull] [Jul 6, 2009]
     * </p>
     * <p>
     * Midified by [修改人] [修改时间]
     * </p>
     * 
     * @param fieldName
     * @return
     */
    private String getGetterOrSetterName(String fieldName, String prdfix)
    {
        StringBuffer getterOrSetterName = new StringBuffer();
        getterOrSetterName.append(prdfix);
        getterOrSetterName.append(fieldName.substring(0, 1).toUpperCase());
        if (getterOrSetterName.length() > 1)
        {
            getterOrSetterName.append(fieldName.substring(1));
        }
        return getterOrSetterName.toString();
    }
    
    public static void main(String[] args)
    {
        User bean = new User();
        bean.setId(123L);
        bean.setUserName("huyvanpull");
        bean.setPassword("123456");
        bean.setDeleteFlag((byte) 1);
        bean.setLoginCount(1L);
        bean.setRemark("测试");
        bean.setLastLoginTime(Calendar.getInstance().getTime());
        bean.setCreateTime(Calendar.getInstance().getTime());
        
        BeanRelectUtil util = new BeanRelectUtil();
        Map<String, Object> fieldNVMap = util.bean2Map(bean);
        
        Object object = util.map2Bean(bean.getClass(), fieldNVMap);
        System.out.println(object);
        
        User userBean = null;
        System.out.println(userBean.getClass());
    }
}