Spring属性编辑器

什么是属性编辑器，作用？
 * 自定义属性编辑器，spring配置文件中的字符串转换成相应的对象进行注入
 spring已经有内置的属性编辑器，我们可以根据需求自己定义属性编辑器

 * 如何定义属性编辑器？
  * 继承PropertyEditorSupport类，覆写setAsText()方法（注意要将处理完成的对象通过PropertyEditorSupport的setValue设置回去）

 *向IoC容器中注册自定义的属性编辑器(两种方式：1 在配置文件中注册 2 在程序中注册)

接下来我们就看看一个关于日期的属性编辑器的部署过程：

首先定义一个测试类：

package com.property;

import java.util.Date;

public class User {
	private String username;
	private Date birthday;
	public String getUsername() {
		return username;
	}
	public void setUsername(String username) {
		this.username = username;
	}
	public Date getBirthday() {
		return birthday;
	}
	public void setBirthday(Date birthday) {
		this.birthday = birthday;
	}

}

 然后继承PropertyEditorSupport,实现自定义的属性编辑器：

package com.property;
import java.beans.PropertyEditorSupport;
import java.util.Date;
import java.text.ParseException;
import java.text.SimpleDateFormat;
public class UtilDatePropertyEditor extends PropertyEditorSupport{
 private String format;
 public UtilDatePropertyEditor(String format) {
  this.format=format;
 }
 public void setAsText(String text) throws IllegalArgumentException {
  SimpleDateFormat sdf=new SimpleDateFormat(format);
  try {
   Date date=sdf.parse(text);
   this.setValue(date);
  } catch (ParseException e) {
   System.out.println(e.getMessage()+"日期的格式不对");
  }
 }
 public void setFormat(String format) {
  this.format = format;
 }
 
}

 接着我们首先定义配置文件：(采用配置方式)

<?xml version="1.0" encoding="UTF-8"?>
 <beans xmlns="http://www.springframework.org/schema/beans" 
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
 xsi:schemaLocation="http://www.springframework.org/schema/beans 
 http://www.springframework.org/schema/beans/spring-beans.xsd
">
<bean id="user" class="com.property.User">
	<property name="username" value="imaginecup"/>
	<property name="birthday" value="1989-05-12"/>
</bean>
<!-- 自定义的属性编辑器 -->
<bean id="customEditorConfigurer" class="org.springframework.beans.factory.config.CustomEditorConfigurer">
		<property name="customEditors">
			<map>
				<entry key="java.util.Date">
					<bean class="com.property.UtilDatePropertyEditor">
						<property name="format" value="yyyy-MM-dd"/>
					</bean>
				</entry>
			</map>
		</property>
	</bean>
</beans>

 

package com.property;

import org.springframework.beans.factory.config.ConfigurableBeanFactory;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.config.CustomEditorConfigurer;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.core.io.ClassPathResource;

public class TestPropertyEditor {
	public static void main(String[] args) {
//		ApplicationContext ac=new ClassPathXmlApplicationContext("applicationContext-*.xml");
//		User user=(User)ac.getBean("user");
//		System.out.println("name:"+user.getUsername()+"\nbirthday:"+user.getBirthday());
		//它等价于
		ConfigurableBeanFactory beanFactory=new XmlBeanFactory(new ClassPathResource("applicationContext-beans.xml"));
		CustomEditorConfigurer configurer=(CustomEditorConfigurer)beanFactory.getBean("customEditorConfigurer");
		configurer.postProcessBeanFactory((ConfigurableListableBeanFactory) beanFactory);
		User user=(User)beanFactory.getBean("user");
		System.out.println("name:"+user.getUsername()+"\nbirthday:"+user.getBirthday());
		
	}

}

 

输出结果：

name:imaginecup
birthday:Fri May 12 00:00:00 CDT 1989

 

接下来我们在程序中注册自定义的属性编辑器：

package com.property;

import org.springframework.beans.PropertyEditorRegistrar;
import org.springframework.beans.PropertyEditorRegistry;
import org.springframework.beans.factory.config.ConfigurableBeanFactory;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.core.io.ClassPathResource;

public class TestPropertyEditorResgister {
	public static void main(String[] args) {
		ConfigurableBeanFactory beanFactory=new XmlBeanFactory(new ClassPathResource("applicationContext-beans.xml"));
		beanFactory.addPropertyEditorRegistrar(new PropertyEditorRegistrar() {
			public void registerCustomEditors(PropertyEditorRegistry registry) {
				registry.registerCustomEditor(java.util.Date.class, new UtilDatePropertyEditor("yyyy-MM-dd"));
				
			}
		});
		User user=(User)beanFactory.getBean("user");
		System.out.println("name:"+user.getUsername()+"\nbirthday:"+user.getBirthday());
		
	}

}