Spring. Net study notes 7-dependent object injection (basic)

1. Property Injection

In the previous article, we briefly mentioned the purpose of dependency injection. Review the content and find that <property name = "tool" ref = "computer"/> is used under the object node. The property tag is used for property injection. Ref is used to identify the object to be associated. The name attribute refers to the property name. As follows:

1. <Object ID = "modernperson" type = "springnetioc. modernperson, springnetioc">
2. <Property name = "tool" ref = "computer"/>
3. </Object>

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Value Type Injection requires the Value Attribute of the property node. For example, <property name = "name" value = "Liu Dong"/>

As the inline type, you can use the following:

1. <Property name = "friend">
2. <Object type = "springnetdi. Person, springnetdi"/>
3. </Property>

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Similarly, the inline type can be a circular reference object (see code ).

2. constructor Injection

Constructor-Arg label is used for Constructor injection. In the same way as property injection, name, ref, and value are used as the attributes of the constructor injection, as follows:

1. <Constructor-Arg name = "argperson" ref = "person"/>
2. <Constructor-Arg name = "intprop" value = "1"/>

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The program code is as follows:

1. Public class person
2. {
3. Public string name {Get; set ;}
4. Public int age {Get; set ;}
5. Public Person friend {Get; set ;}
6. }

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Persondao

1. Public class persondao
2. {
4. Private person argperson;
5. Private int intprop;
7. Public persondao (person argperson, int intprop)
8. {
9. This. argperson = argperson;
10. This. intprop = intprop;
11. }
13. Public void get ()
14. {
15. // Integer parameter of constructor Injection
16. Console. writeline (string. Format ("intprop: {0}", intprop ));
18. // Construct the person injected by the function.
19. Console. writeline (string. Format ("argperson name: {0}", argperson. Name ));
20. Console. writeline (string. Format ("argperson age: {0}", argperson. Age ));
22. // Inline object friend
23. Console. writeline (string. Format ("argperson friend name: {0}", argperson. Friend. Name ));
24. Console. writeline (string. Format ("argperson friend age: {0}", argperson. Friend. Age ));
26. // Circular reference of inline objects
27. Console. writeline (string. Format ("argperson friend name: {0}", argperson. friend. Friend. Name ));
28. Console. writeline (string. Format ("argperson friend age: {0}", argperson. friend. Friend. Age ));
29. }
30. }

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App. config

1. <? XML version = "1.0" encoding = "UTF-8"?>
2. <Configuration>
4. <Configsections>
5. <Sectiongroup name = "Spring">
6. <Section name = "context" type = "Spring. Context. Support. contexthandler, spring. Core"/>
7. <Section name = "objects" type = "Spring. Context. Support. defaultsectionhandler, spring. Core"/>
8. </Sectiongroup>
9. </Configsections>
11. <Spring>
13. <Context>
14. <Resource uri = "config: // spring/objects"/>
15. </Context>
17. <Objects xmlns = "http://www.springframework.net">
19. <Object ID = "person" type = "springnetdi. Person, springnetdi">
20. <! -- Property Value Type Injection -->
21. <Property name = "name" value = "Liu Dong"/>
22. <Property name = "Age" value = "27"/>
24. <! -- Inline object injection -->
25. <Property name = "friend">
26. <Object type = "springnetdi. Person, springnetdi">
27. <Property name = "name" value = "beggar"/>
28. <Property name = "Age" value = "23"/>
29. <Property name = "friend" ref = "person"/>
30. </Object>
31. </Property>
33. </Object>
35. <Object ID = "persondao" type = "springnetdi. persondao, springnetdi">
36. <! -- Constructor injection -->
37. <Constructor-Arg name = "argperson" ref = "person"/>
38. <Constructor-Arg name = "intprop" value = "1"/>
40. </Object>
42. </Objects>
44. </Spring>
46. </Configuration>

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Program

1. Class Program
2. {
3. Static void main (string [] ARGs)
4. {
5. Iapplicationcontext CTX = contextregistry. getcontext ();
7. Persondao Dao = CTX. GetObject ("persondao") as persondao;
8. Dao. Get ();
10. Console. Readline ();
11. }
12. }

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The output result is as follows: