Spring Bean neutron elements lookup-method and Replaced-method

Lookup-method

Example:

Step One: define a Car class

 Package Org.hope.spring.bean.lookup;  Public class Car {    private  String brand;     Private String Corp;     Private Double Price ;    Getter ()&setter () ....}

Step Two: define a boss interface

 Package Org.hope.spring.bean.lookup;  Public Interface Boss {    Car havecar ();}

Step Three: define three beans in spring's configuration file Bean.xml

<BeanID= "Honeqi"class= "Org.hope.spring.bean.lookup.Car"P:brand= "Red Flag"P:price= "400000"Scope= "Prototype" /><BeanID= "BMW"class= "Org.hope.spring.bean.lookup.Car"P:brand= "Mercedes-Benz GLC260"P:price= "500000"Scope= "Prototype" /><BeanID= "Boss"class= "Org.hope.spring.bean.lookup.Boss">    <Lookup-methodname= "Havecar"Bean= "BMW"/></Bean>

Step Four: Write unit test test

 PackageOrg.hope.spring.bean.lookup;Importorg.junit.Test;ImportOrg.junit.runner.RunWith;Importorg.springframework.beans.factory.annotation.Autowired;Importorg.springframework.test.context.ContextConfiguration;ImportOrg.springframework.test.context.junit4.SpringJUnit4ClassRunner; the @RunWith (Springjunit4classrunner.class) @ContextConfiguration (Locations= {"Classpath:bean.xml"}) Public classlookuptest {@AutowiredPrivateboss Boss; @Test Public voidTestboss () {Car car=Boss.havecar ();    System.out.println (Car.getbrand ()); }}

Output:

Mercedes GLC260

Conclusion:

1, through the Lookup-method element tag can provide dynamic implementation for Boss Havecar () , return prototype type of car Bean.

2, the lookup method injection is a certain scope of use, generally in the hope of a singleton bean to get a prototype Bean is used

3, the Lookup method injection needs to use the Cglib class package

Replaced-method (method substitution)

A method that can be replaced with a new method when it is run again

Step one: Create a new Player.java

 PackageOrg.hope.spring.bean.model; Public classPlayer {Private intID; PrivateString name;  Public intgetId () {returnID; }     Public voidSetId (intID) { This. ID =ID; }     PublicString GetName () {returnname; }     Public voidsetName (String name) { This. Name =name; } @Override PublicString toString () {return"player{" + "id=" + ID + ", name= '" + name + ' \ ' + '} '; }}

Step Two: Create a new class that will be replaced

 Package Org.hope.spring.bean.replacedmethod; Import Org.hope.spring.bean.model.Car; Import Org.hope.spring.bean.model.Player;  Public class Yijianlian {    public  player Onplace () {        new  player ();        Player.setname ("Yi Jian Lian");         return player;    }}

Step three: Create a new replacement class to implement Methodreplacer

 PackageOrg.hope.spring.bean.replacedmethod;ImportOrg.hope.spring.bean.model.Player;ImportOrg.springframework.beans.factory.support.MethodReplacer;ImportJava.lang.reflect.Method;/*** @Description: The bean used to replace others must implement Methodreplacer*/ Public classYaoImplementsMethodreplacer { PublicObject Reimplement (Object obj, Method method, object[] args)throwsthrowable {player player=NewPlayer (); Player.setname ("Yao Ming"); returnplayer; }}

Step Four: Configure Bean relationships in Bean2.xml

class class= "Org.hope.spring.bean.replacedmethod.YiJianLian" >     <replaced-method name= "Onplace" Replacer= "Yao"/></bean>

Step Five: Test

 PackageOrg.hope.spring.bean.replacedmethod;Importorg.junit.Test;ImportOrg.junit.runner.RunWith;Importorg.springframework.beans.factory.annotation.Autowired;Importorg.springframework.test.context.ContextConfiguration;ImportOrg.springframework.test.context.junit4.SpringJUnit4ClassRunner; the @RunWith (Springjunit4classrunner.class) @ContextConfiguration (Locations= {"Classpath:bean2.xml"}) Public classreplacedtest {@AutowiredPrivateYijianlian Yijianlian; @Test Public voidTest () {System.out.println (Yijianlian.onplace ()); }}

Output:

Player{id=0, Name= ' Yao Ming '}

Conclusion:

1. You can replace the old method with a new method at run time.

2. The bean used to replace others must implement the Methodreplacer interface.

Reference:

[1] Proficient in spring4.x enterprise application development, electronic industry press, Chen Xionghua

Spring Bean neutron elements lookup-method and Replaced-method