How to initialize a Java Date object in Spring xml

问题:

Consider this simple example -

public class Person
 {
    private String name;
    private Date dateOfBirth;

    // getters and setters here...
 }

In order to initialize Person as a Spring bean, I can write the following.

<bean id = "Michael" class = "com.sampleDomainName.Person">
<property name = "name" value = "Michael" />
</bean>

But in the above bean definition, how can I set the dateOfBirth?

For eg. I want to set the dateOfBirth as

1998-05-07

回答1:

Treat it like any other POJO (which is is)

<property name="dateOfBirth">
  <bean class="java.util.Date" />
</property>

If you need to use an explicit value (such as 1975-04-10), then simply call one of the other constructors (although those which take year-month-day are deprecated). You could also use an explicit java.beans.PropertyEditor which Spring rolls with already (see section 6.4.2; note that you can write your own editors and register them for your own types). You need to register the CustomEditorConfigurer in your config:

<bean class="org.springframework.beans.factory.config.CustomEditorConfigurer">
  <property name="customEditors">
    <map>
      <entry key="java.util.Date" 
             value="org.springframework.beans.propertyeditors.CustomDateEditor"/>
    </map>
  </property> 
</bean>

Then your data looks like:

<property name="dateOfBirth" value="1975-04-10" />

I might add that Date is not an appropriate data type to store a date-of-birth because Date is really an instant-in-time. You might like to look at Joda and use the LocalDate class.

回答2:

One of the answers mentioned here is useful, but it needs additional information. The constructor arguments for the CustomDateEditor need to be supplied.

<bean class="org.springframework.beans.factory.config.CustomEditorConfigurer">
  <property name="customEditors">
    <map>
      <entry key="java.util.Date"> <ref local = "customDateEditor" /> 
      </entry> 
    </map>
  </property> 
</bean>

<bean id = "customDateEditor" class="org.springframework.beans.propertyeditors.CustomDateEditor">
    <constructor-arg>
      <bean class="java.text.SimpleDateFormat">
          <constructor-arg value="yyyy-MM-dd" />
       </bean>
    </constructor-arg>
    <constructor-arg value="true" /> 
</bean>

Now we can do

<property name="dateOfBirth" value="1998-05-07" />

回答3:

Spring inject Date into bean property – CustomDateEditor

This paper give two suggestions:

1. Factory bean
2. CustomDateEditor

I suggest the "Factory Bean" because the CustomDateEditor is not supported in Spring 4.0+ and the Factory Bean is easy enough to use.

<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-2.5.xsd">

    <bean id="dateFormat" class="java.text.SimpleDateFormat">
        <constructor-arg value="yyyy-MM-dd" />
    </bean>

    <bean id="customer" class="com.mkyong.common.Customer">
        <property name="date">
            <bean factory-bean="dateFormat" factory-method="parse">
                <constructor-arg value="2010-01-31" />
            </bean>
        </property>
    </bean>

</beans>

回答4:

Use a CustomDateEditor. It's been in Spring since the early days.