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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;
}
}