Reflection-spring manages beans, injecting the reflection mechanism of bean properties.

#反射

1. is the Java API, is the Java provides the ready-made class!!

--accept the functionality provided by the api!

2. is a dynamic execution mechanism provided by java, dynamically loading classes, dynamically creating objects, dynamically accessing properties, and dynamically invoking METHODS.

# #反射用途

1. The structure of the parsing class in Eclipse uses reflection

2.JUnit recognition tested method uses reflection

--JUNIT3 uses reflection to find the method at the beginning of test

--JUNIT4 uses the reflection analytic @test to find the test method

3.Spring manages bean objects, injecting bean properties using reflection

--create a Bean object instance with reflection

--injecting the Bean's properties with reflection

4. The interpretation of annotations uses the reflection

--support annotations with the reflection API

5. Enforcing private methods (accessing private properties)

Analysis Diagram:

class--package: main/springstru, main/resources

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Springstru/applicationcontext.java

 packagespringstru;Importjava.io.InputStream;Importjava.util.HashMap;Importjava.util.List;Importjava.util.Map;Importorg.dom4j.Document;Importorg.dom4j.Element;Importorg.dom4j.io.SAXReader; public classApplicationContext {//is the Bean object that caches the spring container    Privatemap<string,object> beans =Newhashmap<string, object>(); /*** Initialize the current container with a configuration file * Initialize all Bean objects with an XML configuration file*/     publicApplicationContext (String XML)throwsexception{//use dom4j to read XML files//parse the contents of the XML file to get the Bean's class name and Bean id://dynamically load classes and create objects based on the class name//add an object and the corresponding ID to the map//read stream from resource (classpath)InputStream in =getclass (). getclassloader (). getresourceasstream (xml); Saxreader Reader=NewSaxreader (); Document Doc=Reader.read (in);        In.close (); //Parse Xml: <beans><bean><bean><bean><bean>Element root =doc.getrootelement (); //reads all the bean child elements in the root elementlist<element> list = Root.elements ("bean");  for(Element E:list) {//e is the bean element ID attribute and the class attributeString id = e.attributevalue ("id"); String ClassName= E.attributevalue ("class"); //dynamically loading classes, creating objects dynamicallyClass CLS =Class.forName (className); Object Bean=cls.newinstance ();        Beans.put (id,bean); }    }         publicObject Getbean (String id) {//finds an object in map based on ID and returns the object        returnBeans.get (id); }    //using generic methods: The advantage is that you can reduce the one-time type conversion     public<T> T Getbean (String id,class<t>Cls) {                return(T) Beans.get (id); }}

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Springstru/demo.java

 package   springstru;  public  class   Demo { public  static  void  main (string[] Args) throws   exception{applicationcontext ctx  = new  Applicationco        ntext ("spring-context.xml"  = (foo) ctx.getbean ("foo"  = Ctx.getbean ("foo", foo. 

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/resources/spring-context.xml

<Beans>    <!--Configuring Bean Elements -    <BeanID= "foo"class= "springstru." Foo "></Bean>    <BeanID= "date"class= "java.util.Date"></Bean>    <BeanID= "testCase"class= "demo." TestCase "></Bean></Beans>

Reflection-spring manages beans, injecting the reflection mechanism of bean properties.