BeanUtils框架学习

package com.liang.Instopector;

import java.io.Serializable;
import java.util.Date;

public class Student implements Serializable {
	private String name="liang";
	private int age=21;
	private Date birthday;
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
	public Date getBirthday() {
		return birthday;
	}
	public void setBirthday(Date birthday) {
		this.birthday = birthday;
	}

}

package com.liang.Instopector;

import java.beans.BeanInfo;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

import org.apache.commons.beanutils.BeanUtils;
import org.apache.commons.beanutils.ConvertUtils;
import org.apache.commons.beanutils.Converter;
import org.apache.commons.beanutils.locale.converters.DateLocaleConverter;
import org.junit.Test;

public class Demo {
	//@Test
	public void test1() throws Exception{
		//获得指定的beanInfo对象
		BeanInfo beanInfo = Introspector.getBeanInfo(Student.class);
		//获得属性描述数组
		PropertyDescriptor[] pds = beanInfo.getPropertyDescriptors();
		//遍历：因为类继承Object类，Object类中有一个getClass()方法，所以个数会比你写的多一个
		System.out.println(pds.length);
		for(PropertyDescriptor pd:pds){
			System.out.print(pd.getName()+"  ");
		}
		System.out.println();
		//获得指定的PropertyDescriptor
		PropertyDescriptor pd=new PropertyDescriptor("name", Student.class);
		//获得get方法
		Method m=pd.getReadMethod();
		Student s=new Student();
		String str=(String)m.invoke(s, null);
		System.out.println(str);
		//获得set方法
		Method m1=pd.getWriteMethod();
		m1.invoke(s, "aaa");
		System.out.println(s.getName());
	}

	//@Test
	public void test2() throws Exception{
		Student s=new Student();

		//调用get方法:getProperty返回值是String，因为一切数据都是以String来显示的
		String age= BeanUtils.getProperty(s, "age");
		System.out.println(age);

		//调用set方法：
		//BeanUtils可以进行类型的自动转换，但仅限基本类型：本来需要int型，给个字符串，ok
		BeanUtils.setProperty(s, "name", "aaa");
		BeanUtils.setProperty(s, "age", "123");
		System.out.println("name:"+s.getName());
		System.out.println("age:"+s.getAge());
	}
	//非基本类型的属性设置
	//用户的输入都是String
	//String <----->其他类型间的互相转换
	//用户看到的结果都是String
	@Test
	public void test3() throws Exception{
		Student s=new Student();
		//为BeanUtils注册类型转换器：自定义转换器

		ConvertUtils.register(new Converter() {
			DateFormat df=new SimpleDateFormat("yyyy-MM-dd");
			//type:目标类型
			//value:当前传入的值
			public Object convert(Class type, Object value) {
				if(value instanceof String){//字符串转Date
					String d=(String) value;
					java.util.Date date=null;
					try {
						date=df.parse(d);
					} catch (ParseException e) {
						e.printStackTrace();
					}
					return date;
				}else{//Date转换为字符串
					String date=df.format(value);
					return date;
				}
//				if(type.equals(Date.class)){
//					//字符串转换为Date
//				}else{
//					//Date转换为字符串
//				}
			}
		}, Date.class);
		BeanUtils.setProperty(s, "birthday", "2013-5-12");
		System.out.println(s.getBirthday());
	}
	//利用BeanUtils中写好的Date转换器
	@Test
	public void test4() throws Exception{
		Student s=new Student();
		ConvertUtils.register(new DateLocaleConverter(), Date.class);
		BeanUtils.setProperty(s, "birthday", "2014-10-3");
		System.out.println(s.getBirthday());
	}
}