factory-method: 表示将被调用以注入bean的工厂方法。
factory-bean: 表示将调用工厂方法的bean的引用。如果工厂方法是非静态的,则使用它。
public class A {
public static A getA(){//factory method
return new A();
}
}
<bean id="a" class="com.lidihuo.A" factory-method="getA"></bean>
<bean id="b" class="com.lidihuo.A" factory-method="getB"></bean>
<bean id="a" class="com.lidihuo.A"></bean>
<bean id="b" class="com.lidihuo.A" factory-method="getB" factory-bean="a"></bean>
<bean id="a" class="com.lidihuo.A" factory-method="getA"></bean>
A.java
applicationContext.xml
Test.java
package com.lidihuo;
public class A {
private static final A obj=new A();
private A(){System.out.println("private constructor");}
public static A getA(){
System.out.println("factory method ");
return obj;
}
public void msg(){
System.out.println("hello user");
}
}
<?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:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">
<bean id="a" class="com.lidihuo.A" factory-method="getA"></bean>
</beans>
package org.sssit;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class Test {
public static void main(String[] args) {
ApplicationContext context=new ClassPathXmlApplicationContext("applicationContext.xml");
A a=(A)context.getBean("a");
a.msg();
}
}
private constructor
factory method
hello user
Printable.java
A.java
B.java
PrintableFactory.java
applicationContext.xml
Test.java
package com.lidihuo;
public interface Printable {
void print();
}
package com.lidihuo;
public class A implements Printable{
@Override
public void print() {
System.out.println("hello a");
}
}
package com.lidihuo;
public class B implements Printable{
@Override
public void print() {
System.out.println("hello b");
}
}
package com.lidihuo;
public class PrintableFactory {
public static Printable getPrintable(){
//return new B();
return new A();//return any one instance, either A or B
}
}
<?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:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">
<bean id="p" class="com.lidihuo.PrintableFactory" factory-method="getPrintable"></bean>
</beans>
package org.sssit;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class Test {
public static void main(String[] args) {
ApplicationContext context=new ClassPathXmlApplicationContext("applicationContext.xml");
Printable p=(Printable)context.getBean("p");
p.print();
}
}
hello a
Printable.java
A.java
B.java
PrintableFactory.java
applicationContext.xml
Test.java
package com.lidihuo;
public class PrintableFactory {
//non-static factory method
public Printable getPrintable(){
return new A();//return any one instance, either A or B
}
}
<?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:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">
<bean id="pfactory" class="com.lidihuo.PrintableFactory"></bean>
<bean id="p" class="com.lidihuo.PrintableFactory" factory-method="getPrintable"
factory-bean="pfactory"></bean>
</beans>
hello a