利用反射机制 实现 javabean 转化为 map

package com.test.entity;

import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Type;
import java.util.Collection;
import java.util.Date;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

public class ConvertUtil {

	
	public static Map fromBean(Object object) throws IllegalArgumentException, IllegalAccessException, InstantiationException, InvocationTargetException, ClassNotFoundException
	{
		
		Map<String, Object> map=new HashMap<String, Object>();
		Class class1=object.getClass();
		Field[] fields=class1.getDeclaredFields();
		Method[] methods=class1.getMethods();
		
	
		for(Field eachField:fields)
		{
			
			
			String key=eachField.getName();//字段名称
			
			String methodName="get"+key.substring(0, 1).toUpperCase()+key.substring(1);//方法名称
			
			Method method=getMethodByName(methods, methodName);//得到方法
			
			
			if(eachField.getType().isPrimitive())
			{
				System.out.println(methodName);
				map.put(key, method.invoke(object, null));
				continue;
			}
			
			
			Class theClass=Class.forName(eachField.getType().getName());
					
			if(!Collection.class.isAssignableFrom(theClass)){//不是集合			
				
				
				if(method==null)//get方法存在
					continue;
				try {
					Object result=method.invoke(object, null);//运行方法
					map.put(key, result);//放入map
					
				} catch (InvocationTargetException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}	
			}else {
						
						
				Collection result=(Collection) method.invoke(object, null);
				Iterator it=result.iterator();
				
				
				Object object2=theClass.newInstance();
				Collection collection=(Collection<Map>) object2;
				
				while (it.hasNext()) {
					Object object3=it.next();
					
					Map map2=ConvertUtil.fromBean(object3);
					collection.add(map2);
					
				}
				
				map.put(key, collection);
				
				
			}
			
			
			
			
		}
		
		return map;
		
		
		
	}
	
	private static Method getMethodByName(Method[] methods,String name) {
		
		for(Method each:methods)
		{
			if(each.getName().equals(name))
				return each;
		}
		
		return null;	
		
	}
	

}

package com.test.entity;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.Random;

public class ConvertUtilTest {

	public static void main(String[] args) {
		
		Demo demo=new Demo();
		demo.setStr("abcdefg");
		ArrayList list=new ArrayList<demoitem>();
		
		
		String randomsString="abcdefghijklmnopqrstuvwxyz";
		for(int i=0;i<5;i++)
		{
			DemoItem demoItem=new DemoItem();
			demoItem.setStrr(randomsString.substring(i, i+3));
			list.add(demoItem);			
		}
		demo.setDemoList(list);
		
		
		try {
			Map map=ConvertUtil.fromBean(demo);
			System.out.println(map.toString());
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}		
		
	}
}
</demoitem>

package com.test.entity;

import java.util.ArrayList;
import java.util.List;

public class Demo {

	private String str;
	private ArrayList demoList;
	public String getStr() {
		return str;
	}
	public void setStr(String str) {
		this.str = str;
	}
	public ArrayList getDemoList() {
		return demoList;
	}
	public void setDemoList(ArrayList demoList) {
		this.demoList = demoList;
	}
	@Override
	public String toString() {
		return "Demo [demoList=" + demoList + ", str=" + str + "]";
	}
	
}

package com.test.entity;

public class DemoItem {

	private String strr;

	public String getStrr() {
		return strr;
	}

	public void setStrr(String strr) {
		this.strr = strr;
	}

	@Override
	public String toString() {
		return "DemoItem [strr=" + strr + "]";
	}
	
}