7.5.8: Injection Set Value

If the bean property is a set, you can use the set element.<List.../>, <set.../>, <map.../>And<Props.../>Set attribute values of the list, set, map, and properties types.

Axe. Java:

public interface Axe {public String chop();}

Stoneaxe. Java:

Public class stoneaxe implements axe {@ overridepublic string chop () {return "" ;}@ overridepublic string tostring () {return "";}}

Steelaxe. Java:

Public class steelaxe implements axe {@ overridepublic string chop () {return "Steel axe cutting firewood fast" ;}@ overridepublic string tostring () {return "Steel Axe ";}}

Chinese. Java:

public class Chinese {private List<String> schools;private Map scores;private Map<String,Axe> phaseAxes;private Properties health;private Set axes;private String[] books;public Chinese() {}public void setSchools(List<String> schools) {this.schools = schools;}public void setScores(Map scores) {this.scores = scores;}public void setPhaseAxes(Map<String, Axe> phaseAxes) {this.phaseAxes = phaseAxes;}public void setHealth(Properties health) {this.health = health;}public void setAxes(Set axes) {this.axes = axes;}public void setBooks(String[] books) {this.books = books;}public void test(){System.out.println(schools);System.out.println(scores);System.out.println(phaseAxes);System.out.println(health);System.out.println(axes);System.out.println(Arrays.toString(books));}}

Bean. XML Core Configuration:

<Bean id = "Chinese" class = "com. bean. chinese "> <property name =" Schools "> <list> <value> Primary School </value> <value> secondary school </value> <value> university </value> </ list> </property> <property name = "scores"> <map> <Entry key = "Mathematics" value = "87"/> <Entry key = "English" value = "89"/> <Entry key = "" value = "82"/> </map> </property> <property name = "phaseaxes"> <map> <entry key = "primitive society" value-ref = "stoneaxe"/> <Entry key = "Agricultural Society" value-ref = "steelaxe "/> </Map> </property> <property name =" health "> <props> <prop key =" blood pressure "> normal </prop> <prop key =" height "> 175 </prop> </props> </property> <property name =" axes "> <set> <! -- Each value, bean, and ref is configured with a set element --> <value> common string </value> <Bean class = "com. bean. steelaxe "/> <ref local =" stoneaxe "/> </set> </property> <property name =" books "> <list> <value> crazy Java handouts </ value> <value> detailed description of Java Web and tomcat development technologies </value> <value> lightweight Java EE Enterprise Application practices </value> </List> </property> </bean> <bean id = "stoneaxe" class = "com. bean. stoneaxe "/> <bean id =" steelaxe "class =" com. bean. steelaxe "/>

Test. Java:

public class Test {public static void main(String[] args) {ApplicationContext ctx=new ClassPathXmlApplicationContext("bean.xml");Chinese chinese=(Chinese) ctx.getBean("chinese");chinese.test();}}

Because the set element can also be a basic type value, reference other beans in the container, nested beans, or set attributes, so <list... />, <key... /> and <set... /> the following elements are acceptable:Child Element:

① Value:The Set element is of the basic type or string type.

② Ref:The collection element is another bean instance in the container.

③ Bean:The Set element is a nested bean.

④ List, set, map, and props:The Set element is a set.

<Props.../>Element is used to configure properties of the properties type. The properties type is a special type, and its key and value can only be strings.

Use<Map.../>It is complex to configure the map attribute for an element. Because each element of the map set is composed of two parts: Key and value, each <entry... /> Configure a map element. The entry supports the following four attributes:

① Key:The key of a map is a basic type or string.

② Key-Ref:The map key is another bean instance in the container.

③ Value:The value of map is a basic type or string.

④ Value-Ref:The value of map is another bean instance in the container.