commons beanutils之复制Bean属性

commons beanutils之复制Bean属性

 本文来自：http://fhd001.iteye.com/blog/440930

问题
你有两个相同类型的bean的实例,并需要将其中一个bean的属性复制到另一个中去.

 

解决方案
使用PropertyUtils.copyProperties()方法从一个bean复制属性到另一个bean.其中第一个参数
指定目的bean,而第二个参数是源bean:

Book book = new Book();
book.setName("Prelude to Poundation");
book.setAuthorName("Asimov");

Book destinationBook = new Book();
PropertyUtils.copyProperties(destinationBook,book);

PropertyUtils.copyProperties()方法从源bean实例中检索出所有属性的值,然后将
这些值赋给目的的实例中的相应属性.如果上面的示例中Book bean含有一个Author类型
的author属性,copyProperties()将把相同的引用对象赋给目的bean.换句话说,该方法
没有克隆bean属性的值.如例:
Author author = new Author();
author.setName("Zinsser");

Book book = new Book();
book.setName("On Writing well");
book.setAuthor(author);

Book destinationBook = new Book();
PropertyUtils.copyProperties(destionationBook,book);

if(book.getAuthor() == destinationBook.getAuthor()){
 System.out.println("Author objects identical");
}
现在,两个对象中的author属性值都是Author类同一实例的引用.copyProperyties()并没
有复制bean属性的值.

copyProperties()方法还可以将一个Map的内容复制进bean中,前提是Map各键一一对应于目的
bean的各简单属性:
Map mapOrops = HashMap();
mapProps.put("name","The Art of computer rogramming");
mapProps.put("author","Knuth");

Book destinationBook = new Book();
PropertyUtils.copyProperties(destinationBook,mapProps);

 package test4;

 import java.lang.reflect.InvocationTargetException;
 import java.util.HashMap;
 import java.util.Map;

 import org.apache.commons.beanutils.PropertyUtils;

 /**
  * commons beanutils之复制Bean属性
  * @author fhd001
  */
 public class PropertyUtilsTest7 {

     public static void main(String[] args) {

         /*
          * 例子1 .
          */
         Person p1 = new Person();
         p1.setAge(12 );
         p1.setName("fhd" );

         Person p2 = new Person();
         try {
             PropertyUtils.copyProperties(p2, p1);
         } catch (IllegalAccessException e) {
             e.printStackTrace();
         } catch (InvocationTargetException e) {
             e.printStackTrace();
         } catch (NoSuchMethodException e) {
             e.printStackTrace();
         }
         System.out.println("p2.age: " +p2.getAge()+ "\tp2.name:" +p2.getName());


         /*
          * 例子2 .证明没有克隆bean属性
          */
         Person p3 = new Person();
         p3.setAge(34 );
         p3.setName("ldh" );

         Book b1 = new Book();
         b1.setAuthor(p3);
         b1.setBookName("java" );

         Book b2 = new Book();
         try {
             PropertyUtils.copyProperties(b2, b1);
         } catch (IllegalAccessException e) {
             e.printStackTrace();
         } catch (InvocationTargetException e) {
             e.printStackTrace();
         } catch (NoSuchMethodException e) {
             e.printStackTrace();
         }

         if (b1.getAuthor() == b2.getAuthor()) {
             System.out.println("证明: b1.getAuthor()与b2.getAuthor()返回同一个对象." );
         }


         /*
          * 例子3 .将map中的内容复制到bean中.
          */
         Map<String,Object> m1 = new HashMap<String,Object>();
         m1.put("age" ,  31 );
         m1.put("name" ,  "fhd" );
         Person p6 = new Person();
         try {
             PropertyUtils.copyProperties(p6, m1);
         } catch (IllegalAccessException e) {
             e.printStackTrace();
         } catch (InvocationTargetException e) {
             e.printStackTrace();
         } catch (NoSuchMethodException e) {
             e.printStackTrace();
         }
         System.out.println("p6.name: " +p6.getName()+ "\tp6.age: " +p6.getAge());
     }
 }

package test4;

import java.lang.reflect.InvocationTargetException;
import java.util.HashMap;
import java.util.Map;

import org.apache.commons.beanutils.PropertyUtils;

/**
 * commons beanutils之复制Bean属性
 * @author fhd001
 */
public class PropertyUtilsTest7 {

	public static void main(String[] args) {

		/*
		 * 例子1.
		 */
		Person p1 = new Person();
		p1.setAge(12);
		p1.setName("fhd");
		
		Person p2 = new Person();
		try {
			PropertyUtils.copyProperties(p2, p1);
		} catch (IllegalAccessException e) {
			e.printStackTrace();
		} catch (InvocationTargetException e) {
			e.printStackTrace();
		} catch (NoSuchMethodException e) {
			e.printStackTrace();
		}
		System.out.println("p2.age: "+p2.getAge()+"\tp2.name:"+p2.getName());
		
		
		/*
		 * 例子2.证明没有克隆bean属性
		 */
		Person p3 = new Person();
		p3.setAge(34);
		p3.setName("ldh");
		
		Book b1 = new Book();
		b1.setAuthor(p3);
		b1.setBookName("java");
		
		Book b2 = new Book();
		try {
			PropertyUtils.copyProperties(b2, b1);
		} catch (IllegalAccessException e) {
			e.printStackTrace();
		} catch (InvocationTargetException e) {
			e.printStackTrace();
		} catch (NoSuchMethodException e) {
			e.printStackTrace();
		}
		
		if (b1.getAuthor() == b2.getAuthor()) {
			System.out.println("证明: b1.getAuthor()与b2.getAuthor()返回同一个对象.");
		}
		
		
		/*
		 * 例子3.将map中的内容复制到bean中.
		 */
		Map<String,Object> m1 = new HashMap<String,Object>();
		m1.put("age", 31);
		m1.put("name", "fhd");
		Person p6 = new Person();
		try {
			PropertyUtils.copyProperties(p6, m1);
		} catch (IllegalAccessException e) {
			e.printStackTrace();
		} catch (InvocationTargetException e) {
			e.printStackTrace();
		} catch (NoSuchMethodException e) {
			e.printStackTrace();
		}
		System.out.println("p6.name: "+p6.getName()+"\tp6.age: "+p6.getAge());
	}
}

 

 p2.age:  12   p2.name:fhd
 证明: b1.getAuthor()与b2.getAuthor()返回同一个对象.
 p6.name: fhd    p6.age: 31  ======================================

主要使用：通过一个map接收action里转过来的参数，然后new 一个持久化对象，通过PropertyUtils.copyProperties()转到持久化对象中

请看代码：

  School  s = new School();  ///持久化对象
              s.setSchoolId("11");
              s.setSchoolName("11");
              s.setIntroduce("ddd");
           
              Map<String, String> formMap = new HashMap<String, String>();
              formMap.put("schoolId", "22");
              formMap.put("schoolName", "22");
              PropertyUtils.copyProperties(s, formMap);
              System.out.println(s.getIntroduce());
              System.out.println(s.getSchoolName());
             

打印出来：

ddd
22

还有一个复制类实现类

   1. public class ObjectTransWrap {  
   2.     public static Object wrap(Object actionObj,Class OperatorAction) throws Exception, InstantiationException{  
   3.         Object o = OperatorAction.newInstance();  
   4.         BeanInfo  beanInfo = Introspector.getBeanInfo(actionObj.getClass());  
   5.         PropertyDescriptor[] properties = beanInfo.getPropertyDescriptors();  
   6.         Method get = null;  
   7.         Method  set = null;  
   8.         for (int i = 0; i < properties.length; i++) {  
   9.              try{  
  10.                  get = properties[i].getReadMethod();  
  11.                  set = o.getClass().getMethod( properties[i].getWriteMethod().getName(), new Class[]{properties[i].getPropertyType()});  
  12.              }catch(Throwable a){  
  13.                  continue;  
  14.              }  
  15.              if(set!=null&&get!=null){  
  16.                  set.invoke(o, new Object[]{get.invoke(actionObj, new Object[]{})});  
  17.                  set = null;  
  18.                  get = null;  
  19.              }  
  20.         }  
  21.         return o;  
  22.           
  23.     }