java把實體物件轉化成list和map
阿新 • • 發佈:2019-01-09
普通方式:
某一個實體有較多欄位,想把實體內的資料顯示到excel中去,但是,又不想低效率的一列一列顯示資料
所以,想把實體物件轉化成list,遍歷表格的同時顯示這個實體的資料.
下面是把實體物件轉化成list和map的方法.
需要引用兩個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; } //將javabean實體類轉為map型別,然後返回一個map型別的值 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可是實現map list 實體 dto 之間的相互轉化
參見地址:
http://blog.csdn.net/zhangxiaomin1992/article/details/60757406