普通方式:
某一个实体有较多字段,想把实体内的数据显示到excel中去,但是,又不想低效率的一列一列显示数据
所以,想把实体对象转化成list,遍历表格的同时显示这个实体的数据.
下面是把实体对象转化成list和map的方法.
需要引用两个jar包:commons-beanutils-1.9.2.jar commons-logging-1.2.jar
package Tomap; import java.beans.PropertyDescriptor; import java.lang.reflect.Field; import java.util.ArrayList; import java.util.HashMap; import java.util.Map; import org.apache.commons.beanutils.PropertyUtilsBean; public class ToMap { /** * @param args */ public static void main(String[] args) { ArrayList<String> list=new ArrayList<String>(); testmodel testmodel=new testmodel("zhangmin","nv","18"); list=ConvertObjToMap(testmodel); for(int i=0;i<list.size();i++) { System.out.println(list.get(i)); } /*Map<String, String> map = new HashMap<String, String>(); for (String key : map.keySet()) { System.out.println("key= "+ key + " and value= " + map.get(key)); }*/ } public static ArrayList ConvertObjToMap(Object obj){ ArrayList<String> list=new ArrayList<String>(); if (obj == null) return null; Field[] fields = obj.getClass().getDeclaredFields(); try { for(int i=0;i<fields.length;i++){ try { Field f = obj.getClass().getDeclaredField(fields[i].getName()); f.setAccessible(true); Object o = f.get(obj); list.add(o.toString()); } catch (NoSuchFieldException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IllegalArgumentException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IllegalAccessException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } catch (SecurityException e) { // TODO Auto-generated catch block e.printStackTrace(); } return list; } //将javabean实体类转为map类型,然后返回一个map类型的值 public static HashMap<String, Object> beanToMap(Object obj) { HashMap<String, Object> params = new HashMap<String, Object>(0); try { PropertyUtilsBean propertyUtilsBean = new PropertyUtilsBean(); PropertyDescriptor[] descriptors = propertyUtilsBean.getPropertyDescriptors(obj); for (int i = 0; i < descriptors.length; i++) { String name = descriptors[i].getName(); if (!"class".equals(name)) { params.put(name, propertyUtilsBean.getNestedProperty(obj, name)); } } } catch (Exception e) { e.printStackTrace(); } return params; } }
其他方式,使用dozer可是实现map list 实体 dto 之间的相互转化
参见地址:
http://blog.csdn.net/zhangxiaomin1992/article/details/60757406