Spring in Action②

Initializing and destroying beans

Init-method && Destory-method

<id= "Auditorium"  class= "Test." Audirorium "  init-method=" Turnonlights "  destory-method=" Turnofflights " />

If many beans in the context have the same name as the initialization method and the Destroy method. Can be declared in the Default-init-method && Default-destory-method method of the beans element.

<xmlns=**********    default-init-method= "Init"     Default-destroy-method= "destory">   <Bean/> .... < Beans >

Using the <property> element to configure bean properties, you need to invoke the setter method of the property to inject.

Similar to the following:

<name= "Age"  value= "/> "

Name Space P

<*********    xmlns:p= "http://www.springframework.org/schema/p"> ....    <  = "/>"   <p:instrument-ref= "saxophone"  />

Internal Bean (inner bean): Two types can be injected using the setter and the constructor.

< Propertyname= "instrument">    <Beanclass= "Test. Saxophone "/></ Property>similar:<BeanID= "saxophone"class= "Test. Saxophone "/>...  < Propertyname= "instrument"ref= "saxophone"/>...

Assembly set: Various collections can be assembled, such as Java.util.List, Java.util.Set, Java.util.Collection, java.util.map,java.util.properties and so on. You can set properties and null values.

<list> Repeatable

<set> Non-repeatable

<map> Name value can be any type

<props> Name value must be of type string

< Propertyname= "Instruments">    <List>        <refBean= "Guitar"/>        <refBean= "Harmonica"/>    </List></ Property>*****************************************< Propertyname= "Instruments">    <List>        <refBean= "Guitar"/>        <refBean= "Guitar"/>    </List></ Property>*****************************************< Propertyname= "Instruments">    <Map>        <entryKey= "Guitar"Value-ref= "Guitar"/>        <entryKey= "Hamonica"Value-ref= "Harmonica"/>    </Map></ Property>***************************************key:entry key is a string type when the Key-ref:entry key is a different bean when value: Entry value is a string type when Value-ref:entry value is a different bean ***************************************< Propertyname= "Instruments">    <Props>        <propKey= "Guitar">Guitar hum hum hum</prop>        <propKey= "Hamonica"><NULL/></prop>    </Props></ Property>

Assembling with an expression

Spel (Spring Expression Language)

Literal value

< Propertyname= "Count"value= "#{5}"/>< Propertyname= "Count"value= "#{5.98}"/>< Propertyname= "Name"value= "#{' Chuck '}"/>< Propertyname= "Enable"value= "#{true}"/>

Reference Bean

<!--Reference Bean -< Propertyname= "instrument"value= "#{guitar}"/>< Propertyname= "instrument"ref= "Guitar"/><!--will call Kenny.getinstrument () -< Propertyname= "instrument"ref= "#{kenny.instrument}"/>< Propertyname= "Song"ref= "#{kenny.selectsong (). toUpperCase ()}"/><!--avoid null pointer exceptions, use the?. instead. Ensure that the left value is not null - < Propertyname= "Song"ref= "#{kenny.selectsong ()?". toUpperCase ()} "/>

Method of calling Class: T () operator

< ...     value = "#{t (java.lang.Math). PI} "/>

Using Spel for numeric operations

<...  value= "#{counter.total +"/><...  value= "#{t (java.lang.Math). PI * circle.radius^2} "/><!--Compare Values -<...  value= "#{circle.radius le"/><!--le less or equal -<!--eq equal -<!--LT Less -<!--GT Great -<!--ge Great or Equal -<!--logical expression and or not -<!--conditional expression? : -<!--Regular Expressions -<...  value= "#{admin.email matches ' [A-za-z0-9._%+-][email protected][a-za-z0-9.-]+\\.com '? "Right Email ":" Wrong Email "}"

Using Spel to filter collections

 Public class city{    private  String name;     Private String State;     Private Integer population;}

<util:listID= "Cities">    <Beanclass= "Test. City "P:name= "Chicago"p:state "IL" P:population= "232322"/>    <Beanclass= "Test. City "P:name= "Houston"p:state "TX" P:population= "235452"/></util:list><!--Accessing Collections -<... value= "#{cities[1]}"/>

Load Properties configuration file

<id= "Settings"  location= "Classpath:settings.properties" /> <  value= "#{settings[' Twitter.accesstoken '}"/>

Systemenvironment all environment variables on the machine

Systemproperties contains all the properties set at Java startup (usually with the-D parameter)

<name= "HomePath"  value= "#{systemenvironment[' HOME"} "/ ><name= "HomePath"  value= "#{systemproperties[" Application.home ']} "

Spel Query Collection

The query operator.? [] (all occurrences). ^[] (first occurrence). $[] Last Occurrence

Eg cities.? [Population GT 10000]---Collection

Projection operator.! []

Eg cities.! [Name] contains only the city name of the string type collection

cities.! [Name + ', ' + state] contains a collection of string types for city names and regions

Spring in Action②