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());
}
}