Spring Dependencies Injection

Spring Dependencies Injection1, Construtor argsinjection1.1 Ref injection

<beans> <bean id= "foo" class= "X.y.foo" > <constructor-arg ref= "bar"/> <constructor-ar G ref= "Baz"/> </bean> <bean id= "bar" class= "X.y.bar"/> <bean id= "baz" class= "X.y.baz"/></ Beans>package X.y;public class Foo {public Foo (bar bar, Baz Baz) {//...}}

An injection is performed based on the type matching the corresponding constructor parameter.

1.2 Specifying type Injection

public class Examplebean {//number of years to calculate the Ultimate Answer private int years;    The Answer to life, the Universe, and everything private String ultimateanswer;    Public Examplebean (int years, String ultimateanswer) {this.years = years;    This.ultimateanswer = Ultimateanswer; }}<bean id= "Examplebean" class= "examples. Examplebean "> <constructor-arg type=" int "value=" 7500000 "/> <constructor-arg type=" Java.lang.String "Val Ue= "/></bean>"

1.3 Specify Index Injection

<bean id= "Examplebean" class= "examples. Examplebean "> <constructor-arg index=" 0 "value=" 7500000 "/> <constructor-arg index=" 1 "value="/>< " ;/bean>

1.4 Using Annotation Injection

Package Examples;public class Examplebean {//Fields omitted @ConstructorProperties ({"Years", "Ultimateanswer"})        Public Examplebean (int years, String ultimateanswer) {this.years = years;    This.ultimateanswer = Ultimateanswer; }}

2, setter-based Dependency Injection

It is time to use the constructor to inject, when to use the setter, an experience said: the necessary parameters need to be injected into the constructor, the other can be used setter, but also can be used @required annotation to display the specified parameters

2.1 Simple Set-injection

Public class simplemovielister {    // the simplemovielister  has a dependency on the MovieFinder    private  moviefinder moviefinder;    // a setter method so that  The spring container can inject a moviefinder    public  void setmoviefinder (Moviefinder moviefinder)  {         this.movieFinder = movieFinder;    }    //  business logic that actually uses the injected moviefinder is  Omitted ...} <bean id= "Simplemovielister"  class =  "..." >    <property  name =  "Moviefinder"  ref =  "Moviefinder" ></property></bean>

2.2

Spring Dependencies Injection