Spring学习笔记之二“属性注入”

参见附件代码理解下文（附件中有更加详细的注解）
一、普通的属性注入

1)bean类

package com.bjsxt.spring;

import java.util.Date;
import java.util.List;
import java.util.Map;
import java.util.Set;

public class Bean1 {
	
	private String strValue;
	
	private int intValue;
	
	private List listValue;
	
	private Set setValue;
	
	private String[] arrayValue;
	
	private Map mapValue;
	
	private Date dateValue;

	public String getStrValue() {
		return strValue;
	}

	public void setStrValue(String strValue) {
		this.strValue = strValue;
	}

	public int getIntValue() {
		return intValue;
	}

	public void setIntValue(int intValue) {
		this.intValue = intValue;
	}

	public List getListValue() {
		return listValue;
	}

	public void setListValue(List listValue) {
		this.listValue = listValue;
	}

	public Set getSetValue() {
		return setValue;
	}

	public void setSetValue(Set setValue) {
		this.setValue = setValue;
	}

	public String[] getArrayValue() {
		return arrayValue;
	}

	public void setArrayValue(String[] arrayValue) {
		this.arrayValue = arrayValue;
	}

	public Map getMapValue() {
		return mapValue;
	}

	public void setMapValue(Map mapValue) {
		this.mapValue = mapValue;
	}

	public Date getDateValue() {
		return dateValue;
	}

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

2）相应的xml文件

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"
	     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	     xmlns:aop="http://www.springframework.org/schema/aop"
	     xmlns:tx="http://www.springframework.org/schema/tx"
	     xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd
           http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.0.xsd
           http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.0.xsd">
	
	<bean id="bean1" class="com.bjsxt.spring.Bean1">
		<property name="strValue" value="Hello"/>
		<!-- 
		<property name="intValue" value="123"/>
		 -->
		 <property name="intValue">
		 	<value>123</value>
		 </property>
		 <property name="listValue">
		 	<list>
		 		<value>list1</value>
		 		<value>list2</value>
		 	</list>
		 </property>
		 <property name="setValue">
		 	<set>
		 		<value>set1</value>
		 		<value>set2</value>
		 	</set>
		 </property>
		 <property name="arrayValue">
		 	<list>
		 		<value>array1</value>
		 		<value>array2</value>
		 	</list>
		 </property>
		 <property name="mapValue">
		 	<map>
		 		<entry key="k1" value="v1"/>
		 		<entry key="k2" value="v2"/>
		 	</map>
		 </property>
		 <property name="dateValue">
		 	<value>2008-08-15</value>
		 </property>
	</bean>
	
	<bean id="bean2" class="com.bjsxt.spring.Bean2">
		<property name="bean3" ref="bean3"/>
		<property name="bean4">
			<ref bean="bean4"/>
		</property>	
		<property name="bean5" ref="bean5"/>
	</bean>
	
	<!-- 
	<bean id="bean3" class="com.bjsxt.spring.Bean3">
		<property name="id" value="1000"/>
		<property name="name">
			<value>Jack</value>
		</property>
		<property name="password" value="123"/>
	</bean>
	
	<bean id="bean4" class="com.bjsxt.spring.Bean4">
		<property name="id" value="1000"/>
		<property name="name" value="Jack"/>
	</bean>
	 -->
	 
	<bean id="bean5" class="com.bjsxt.spring.Bean5">
		<property name="age" value="20"/>
	</bean>
</beans>

 3）相应的测试代码

 

package com.bjsxt.spring;

import org.springframework.beans.factory.BeanFactory;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import junit.framework.TestCase;

public class InjectionTest extends TestCase {
	
	private BeanFactory factory;
	
	@Override
	protected void setUp() throws Exception {
		factory = new ClassPathXmlApplicationContext("applicationContext-*.xml");	
	}

	public void testInjection1() {
		Bean1 bean1 = (Bean1)factory.getBean("bean1");
		
		System.out.println("bean1.strValue=" + bean1.getStrValue());
		System.out.println("bean1.intValue=" + bean1.getIntValue());
		System.out.println("bean1.listValue=" + bean1.getListValue());
		System.out.println("bean1.setValue=" + bean1.getSetValue());
		System.out.println("bean1.arrayValue=" + bean1.getArrayValue());
		System.out.println("bean1.mapValue=" + bean1.getMapValue());
		System.out.println("bean1.dateValue=" + bean1.getDateValue());
	}}
	

 

 

spring的普通属性注入 
参见：spring文档3.3章节
 
二、什么是属性编辑器，作用？

 

如上例中如果注解Date属性，Spring就会报错，那么怎么办呢。Spring给我们提供了属性编辑器相当于Struts的convert方法，对注入的属性可以进行转换。

 

* 自定义属性编辑器，当spring遇到需要转换的类型时，该类型一般就是applicationContext-editor.xml中的Key所表示的类型（如本例中的<entry key="java.util.Date">），那么当在spring会自动将注入的字符串转换成相应的需要转换的对象进行注入
 

   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类
 * 如何定义属性编辑器？
  * 1、继承PropertyEditorSupport类，覆写setAsText()方法，编写自己写的UtilDatePropertyEditor.java
类。参见：UtilDatePropertyEditor.java

package com.bjsxt.spring;

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

/**
 * java.util.Date属性编辑器 
 * @author Administrator
 *
 */
public class UtilDatePropertyEditor extends PropertyEditorSupport {

	private String format="yyyy-MM-dd";
	
	@Override
	public void setAsText(String text) throws IllegalArgumentException {
		System.out.println("UtilDatePropertyEditor.saveAsText() -- text=" + text);
		
		SimpleDateFormat sdf = new SimpleDateFormat(format);
		try {
			Date d = sdf.parse(text);
			this.setValue(d);
		} catch (ParseException e) {
			e.printStackTrace();
		}
	}

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

}

 
  * 2、将UtilDatePropertyEditor.java属性编辑器注册到spring内置的属性编辑器类中，参见：applicationContext-editor.xml（注册时还可以注入相应的属性）

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"
	     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	     xmlns:aop="http://www.springframework.org/schema/aop"
	     xmlns:tx="http://www.springframework.org/schema/tx"
	     xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd
           http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.0.xsd
           http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.0.xsd">
     <!-- 定义属性编辑器 -->      
	<bean id="customEditorConfigurer" class="org.springframework.beans.factory.config.CustomEditorConfigurer">
		<property name="customEditors">
			<map>
				<entry key="java.util.Date">
					<bean class="com.bjsxt.spring.UtilDatePropertyEditor">
						<property name="format" value="yyyy-MM-dd"/>
					</bean>
				</entry>
			</map>
		</property>
	</bean>	
	
	<!-- 
	<bean id="utilDatePropertyEditor" class="com.bjsxt.spring.UtilDatePropertyEditor"></bean>
	 -->
</beans>

 

 

三、公共的注入  
依赖对象的注入方式，可以采用：
 * ref属性
 * <ref>标签
 * 内部<bean>来定义
 
如何将公共的注入定义描述出来？
 * 通过<bean>标签定义公共的属性，指定abstract=true
 * 具有相同属性的类在<bean>标签中指定其parent属性
 
 参见：applicationContext-other.xml

 

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"
	     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	     xmlns:aop="http://www.springframework.org/schema/aop"
	     xmlns:tx="http://www.springframework.org/schema/tx"
	     xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd
           http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.0.xsd
           http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.0.xsd">
   
   <bean id="beanAbstract" abstract="true">
   		<property name="id" value="1000"/>
   		<property name="name" value="Jack"/>
   </bean>         
   
   <bean id="bean3" class="com.bjsxt.spring.Bean3" parent="beanAbstract">
   		<property name="name" value="Tom"/>
   		<property name="password" value="123"/>
   </bean>        
   
   <bean id="bean4" class="com.bjsxt.spring.Bean4" parent="beanAbstract"/>
</beans>

 

测试代码

package com.bjsxt.spring;

import org.springframework.beans.factory.BeanFactory;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import junit.framework.TestCase;

public class InjectionTest extends TestCase {
	
	private BeanFactory factory;
	
	@Override
	protected void setUp() throws Exception {
		factory = new ClassPathXmlApplicationContext("applicationContext-*.xml");	
	}

		
	public void testInjection2() {
		Bean2 bean2 = (Bean2)factory.getBean("bean2");
		
		System.out.println("bean2.bean3.id=" + bean2.getBean3().getId());
		System.out.println("bean2.bean3.name=" + bean2.getBean3().getName());
		System.out.println("bean2.bean3.password=" + bean2.getBean3().getPassword());
		System.out.println("bean2.bean4.id=" + bean2.getBean4().getId());
		System.out.println("bean2.bean4.name=" + bean2.getBean4().getName());
		System.out.println("bean2.bean5.age=" + bean2.getBean5().getAge());
	}
	
}