Javaee--spring_ioc02

Three ways to instantiate a bean

　　1, using the non-parametric construction of the class to create (emphasis)

<bean id= "User" class= "class full path" ></bean>

An exception is reported if the class does not have a parameterless construct

2. Create with Static factory

(1) Creating a static method in the factory class returns the class object

public class userfactory{

public static User GetUser () {

return new User ();

}

}

(2) Create an object in the spring configuration file

<bean id= "user" class= "factory class full path" factory-method= "GetUser" ></bean>

3. Create with Instance factory

(1) Create a method that is not static returns a class object

　　　　　　　　　　public class userfactory{

Public User GetUser () {

return new User ();

}

}

(2)

<bean id= "Userfactory" class= "Full path to factory class" ></bean>

<bean id= "user" factory-bean= "userfactory" factory-method= "GetUser" ></bean>

Second, the bean label commonly used properties

　　　　ID attribute: Name, can be arbitrarily named, cannot use special symbol, according to ID value can get configuration object

Class Property: The full path of the class in which the object is created

Name property: As with the ID property, special symbols can be used

Scope Property:

value:Singleton: Singleton (default value )

Prototype: multiple examples of

Request:spring create an object put it in the request domain

Session:spring create an object and put it in the session field

Globalsession: Application in Porlet environment, if there is no porlet environment, then the equivalent session

Third, attribute injection

　　　　The first type: using the Set method to inject

public class user{

private String name;

public void SetName (String name) {

This.name=name;

}

}

The second type: using a parametric construction injection

public class user{

private String name;

User (String name) {

This.name=name;

}

}

The third type: interface injection

public interface userdao{

public void DeleteUser ();

}

　　　　　　　　　　Public Userdaoimp implements userdao{

private String name;

public void DeleteUser (String name) {

This.name=name;

...

}

}

Only the first two types of injections are supported in spring

1. Set method injection configuration (emphasis)

<bean id= "User" class= "class full path" >

<property name= "Property name" Value= "Property value" ></property>

</bean>

2. Using a parametric structure injection

<bean id= "User" class= "class full path" >

<constructor-arg name= "Property name" Value= "Property value" ></constructor-arg>

</bean>

3. Inject the attributes of the object type (to inject DAO into the service as an example)

(1) Use DAO as attribute in service

(2) Set method to generate a DAO Type property

(3) <.bean id= "userdao" class= "DAO's full path" ></bean>

<bean id= "UserService" class= "full path to service" >

<property name= "Property name" ref= "Userdao" ></property>

</bean>

4, p name space injection

Add to constraint: <bean

xmlns:p= "http://www.springframework.org/schema/P"

>

<bean id= "User" class= "class full path" P: Property name = "attribute value"></bean>

5. Complex attribute Injection

Injected array type:

< Bean id= "user" class= "full Path to Class" >

<property name= "Property name" >

<list>

<value> attribute Values </value>

<value> attribute Values </value>

</list>

</property>

</bean>

Inject list type

　　　　　　　　　<bean id= "User" class= "class full path" >

<property name= "property name" >

<list>

<value> attribute Values </value>

<value> attribute Values </value>

</list>

</property>

</bean>

Inject map type

　　　　　　　　　<bean id= "User" class= "class full path" >

<property name= "property name" >

<map>

<entry key= "key" value= "value" ></entry>

<entry key= "key" value= "value" ></entry>

</map>

</property>

</bean>

Injection Properties Type

　　　　　　　　　<bean id= "User" class= "class full path" >

<property name= "property name" >

<props>

<prop key= "Key" > Value </prop>

<prop key= "Key" > Value </prop>

</props>

</property>

</bean>

Iv. differences between the IOC and DI

　　　　　　(1) IOC: Control reversal, give the object to spring configuration

(2) Di: Dependency Injection: Setting a value to a property inside a class

(3) Relationship: Dependency injection cannot exist alone and needs to be done on an IOC basis

Javaee--spring_ioc02