spring4.0之后，自定义属性编辑器的配置变化

问题：spring中注入时间日期（java.util.Date）类型的属性的时候需要进行类型转换，因为spring不能直接注入Date类型。之前学习spring的时候是学的spring 2.5的版本，但是今天把spring的包都换成了spring 4.2 的，发现之前的出现错误。

具体的错误信息如下：

log4j:WARN No appenders could be found for logger (org.springframework.core.env.StandardEnvironment).
log4j:WARN Please initialize the log4j system properly.
Exception in thread "main" org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'customEditorConfigurer' defined in file [E:\Workspaces\MyEclipse 10\spring_utildate\bin\applicationContext-beans.xml]: Initialization of bean failed; nested exception is org.springframework.beans.TypeMismatchException: Failed to convert property value of type [java.util.LinkedHashMap] to required type [java.util.Map] for property 'customEditors'; nested exception is java.lang.IllegalArgumentException: Cannot convert value of type [com.zm.bean.UtilDatePropertyEditor] to required type [java.lang.Class] for property 'customEditors[java.util.Date]': PropertyEditor [org.springframework.beans.propertyeditors.ClassEditor] returned inappropriate value of type [com.zm.bean.UtilDatePropertyEditor]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:553)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
    at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:171)
    at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:678)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:520)
    at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:139)
    at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:83)
    at com.zm.test.Test.main(Test.java:11)
Caused by: org.springframework.beans.TypeMismatchException: Failed to convert property value of type [java.util.LinkedHashMap] to required type [java.util.Map] for property 'customEditors'; nested exception is java.lang.IllegalArgumentException: Cannot convert value of type [com.zm.bean.UtilDatePropertyEditor] to required type [java.lang.Class] for property 'customEditors[java.util.Date]': PropertyEditor [org.springframework.beans.propertyeditors.ClassEditor] returned inappropriate value of type [com.zm.bean.UtilDatePropertyEditor]
    at org.springframework.beans.AbstractNestablePropertyAccessor.convertIfNecessary(AbstractNestablePropertyAccessor.java:596)
    at org.springframework.beans.AbstractNestablePropertyAccessor.convertForProperty(AbstractNestablePropertyAccessor.java:603)
    at org.springframework.beans.BeanWrapperImpl.convertForProperty(BeanWrapperImpl.java:204)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.convertForProperty(AbstractAutowireCapableBeanFactory.java:1527)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1486)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1226)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:543)
    ... 11 more
Caused by: java.lang.IllegalArgumentException: Cannot convert value of type [com.zm.bean.UtilDatePropertyEditor] to required type [java.lang.Class] for property 'customEditors[java.util.Date]': PropertyEditor [org.springframework.beans.propertyeditors.ClassEditor] returned inappropriate value of type [com.zm.bean.UtilDatePropertyEditor]
    at org.springframework.beans.TypeConverterDelegate.convertIfNecessary(TypeConverterDelegate.java:298)
    at org.springframework.beans.TypeConverterDelegate.convertToTypedMap(TypeConverterDelegate.java:655)
    at org.springframework.beans.TypeConverterDelegate.convertIfNecessary(TypeConverterDelegate.java:222)
    at org.springframework.beans.AbstractNestablePropertyAccessor.convertIfNecessary(AbstractNestablePropertyAccessor.java:576)
    ... 17 more

经过查看日志得到的提示是，自定义的编辑器类型与要求的类型不匹配。由于之前一点代码没有改动，只是将spring 2.0 的包换成了spring 4.0的包，因此，感觉应该不是代码的问题。只能说明是spring 4.0的新特性所致。于是开始跟踪源码，最后终于发现了“惊天大幂幂”。。。

Spring 2.0的配置

bean类：

package com.zm.bean;

import java.util.Date;

public class Bean1 {
    private Date dateValue;

    public Date getDateValue() {
        return dateValue;
    }

    public void setDateValue(Date dateValue) {
        this.dateValue = dateValue;
    }

}

自定义属性编辑器类(UtilDatePropertyEditor)：

package com.zm.bean;

import java.beans.PropertyEditorSupport;
import java.text.SimpleDateFormat;
import java.text.ParseException;
import java.util.Date;

public class UtilDatePropertyEditor extends PropertyEditorSupport {

    private String format="yyyy-MM-dd";

    @Override
    public void setAsText(String text) throws IllegalArgumentException {
        // TODO Auto-generated method stub
        System.out.println("UtilDatePropertyEditor.setAsText() -- text=" + text);

        SimpleDateFormat sdf = new SimpleDateFormat(format);
        try{
            Date d = sdf.parse(text);
            this.setValue(d);
        }catch (ParseException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    public void setFormat(String format) {
        this.format = format;
    }

}

相关配置：

<span style="white-space:pre">    span>
    <bean id="bean1" class="com.zm.bean.Bean1">
         <property name="dateValue" value="2016-08-20"/>
    bean>

    <bean id="customEditorConfigurer" class="org.springframework.beans.factory.config.CustomEditorConfigurer">
        <property name="customEditors">
            <map>
                <entry key="java.util.Date" >
                    <bean class="com.zm.bean.UtilDatePropertyEditor">
                        <property name="format" value="yyyy-MM-dd"/>
                    bean>
                entry>
            map>
        property>
    bean>

Spring 4.0的配置

相关配置：

<span style="white-space:pre">    span>
    <bean id="bean1" class="com.zm.bean.Bean1">
         <property name="dateValue" value="2016-08-20"/>
    bean>

    <bean id="customEditorConfigurer" class="org.springframework.beans.factory.config.CustomEditorConfigurer">
        <property name="customEditors">
            <map>
                <entry key="java.util.Date" value="com.zm.bean.UtilDatePropertyEditor"/>
            map>
        property>
    bean>

对比上面的配置可以发现，唯一的区别在于，在配置customEditors属性的时候，spring2.0配置的的value是一个，而spring4.0配置的的value是类名。

 查看源码可以发现customEditors的类型，在spring2.0 中是Map类型，key和value的类型并不确定，但是底层处理的时候，key的类型必须是Class类型，而value是一个注入的bean；在spring4.0中，customEditors的类型变为了Map, Class>， 也就是说，key和value的类型已经确定为Class类型。