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BeanUtils的populate方法之日期处理

BeanUtils.populate(Obj, Map);可以使map转对象，但是如果是Obj有个日期字段而Map中这个字段为空时候就会报错，无法赋值，这个时候就需要一个日期转换器！

首先写一个日期转换器

package com.hzdl.examination.web;

import org.apache.commons.beanutils.BeanUtilsBean;
import org.apache.commons.beanutils.ConvertUtilsBean;
import org.apache.commons.beanutils.Converter;
import org.apache.commons.beanutils.PropertyUtilsBean;

import java.text.DateFormat;
import java.text.DateFormatSymbols;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;
import java.util.Map;

public class DateTimeConverter implements Converter { 
   
    private static final String DATE = "yyyy-MM-dd";
    private static final String DATETIME = "yyyy-MM-dd HH:mm:ss";
    private static final String TIMESTAMP = "yyyy-MM-dd HH:mm:ss.SSS";

    @Override
    public Object convert(Class type, Object value) { 
   
        // TODO Auto-generated method stub
        return toDate(type, value);
    }

    public static Object toDate(Class type, Object value) { 
   
        if (value == null || "".equals(value))
            return null;
        if (value instanceof String) { 
   
            String dateValue = value.toString().trim();
            int length = dateValue.length();
            if (type.equals(java.util.Date.class)) { 
   
                try { 
   
                    DateFormat formatter = null;
                    if (length <= 10) { 
   
                        formatter = new SimpleDateFormat(DATE, new DateFormatSymbols(Locale.CHINA));
                        return formatter.parse(dateValue);
                    }
                    if (length <= 19) { 
   
                        formatter = new SimpleDateFormat(DATETIME, new DateFormatSymbols(Locale.CHINA));
                        return formatter.parse(dateValue);
                    }
                    if (length <= 23) { 
   
                        formatter = new SimpleDateFormat(TIMESTAMP, new DateFormatSymbols(Locale.CHINA));
                        return formatter.parse(dateValue);
                    }
                } catch (Exception e) { 
   
                    e.printStackTrace();
                }
            }
        }
        return value;
    }
			//调用此方法封装bean map为requeset.getParamteMap，object为空对象
    public static void transMap2Bean(Map<String, Object> map, Object obj) { 
   

        try { 
   
            DateTimeConverter dtConverter = new DateTimeConverter();
            ConvertUtilsBean convertUtilsBean = new ConvertUtilsBean();
            convertUtilsBean.deregister(Date.class);
            convertUtilsBean.register(dtConverter, Date.class);
            BeanUtilsBean beanUtilsBean = new BeanUtilsBean(convertUtilsBean,
                    new PropertyUtilsBean());
            beanUtilsBean.populate(obj, map);

        } catch (Exception e) { 
   

        }

        return;

    }


}