spring
ApplicationContextの設定

備考

Javaの設定

Javaの設定は通常、 @Configurationアノテーションをクラスに適用して、クラスにBean定義が含まれることを示唆することによって行われます。 Bean定義は、オブジェクトを返すメソッドに@Beanアノテーションを適用することによって指定されます。

@Configuration // This annotation tells the ApplicationContext that this class
               // contains bean definitions.
class AppConfig {
    /**
     * An Author created with the default constructor
     * setting no properties
     */
    @Bean // This annotation marks a method that defines a bean 
    Author author1() {
        return new Author();
    }

    /**
     * An Author created with the constructor that initializes the 
     * name fields
     */
    @Bean
    Author author2() {
        return new Author("Steven", "King");
    }

    /**
     * An Author created with the default constructor, but  
     * then uses the property setters to specify name fields
     */
    @Bean
    Author author3() {
        Author author = new Author();
        author.setFirstName("George");
        author.setLastName("Martin");
        return author;
    }

    /**
     * A Book created referring to author2 (created above) via
     * a constructor argument.  The dependency is fulfilled by
     * invoking the method as plain Java.
     */
    @Bean
    Book book1() {
        return new Book(author2(), "It");
    }

    /**
     * A Book created referring to author3 (created above) via
     * a property setter.  The dependency is fulfilled by
     * invoking the method as plain Java.
     */
    @Bean
    Book book2() {
        Book book = new Book();
        book.setAuthor(author3());
        book.setTitle("A Game of Thrones");
        return book;
    }
}

// The classes that are being initialized and wired above...
class Book { // assume package org.springframework.example
    Author author;
    String title;
    
    Book() {} // default constructor
    Book(Author author, String title) {
        this.author = author;
        this.title= title;
    }

    Author getAuthor() { return author; }
    String getTitle() { return title; }

    void setAuthor(Author author) {
        this.author = author;
    }

    void setTitle(String title) {
        this.title= title;
    }
}

class Author { // assume package org.springframework.example
    String firstName;
    String lastName;

    Author() {} // default constructor
    Author(String firstName, String lastName) {
        this.firstName = firstName;
        this.lastName = lastName;
    }

    String getFirstName() { return firstName; }
    String getLastName() { return lastName; }

    void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    void setLastName(String lastName) {
        this.lastName = lastName;
    }
}

Xmlの設定

Xmlの設定は通常、Springの特定のbeansスキーマを使用してxmlファイル内にBeanを定義することによって行われます。ルートbeans要素の下で、典型的なBean定義はbeanサブ要素を使用して行われます。

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
                        http://www.springframework.org/schema/beans/spring-beans.xsd">
    <!-- An Author created with the default constructor
         setting no properties -->
    <bean id="author1" class="org.springframework.example.Author" />
    
    <!-- An Author created with the constructor that initializes the 
         name fields -->
    <bean id="author2" class="org.springframework.example.Author">
        <constructor-arg index="0" value="Steven" />
        <constructor-arg index="1" value="King" />
    </bean>

    <!-- An Author created with the default constructor, but  
         then uses the property setters to specify name fields -->
    <bean id="author3" class="org.springframework.example.Author">
        <property name="firstName" value="George" />
        <property name="lastName" value="Martin" />
    </bean>

    <!-- A Book created referring to author2 (created above) via
         a constructor argument -->
    <bean id="book1" class="org.springframework.example.Book">
        <constructor-arg index="0" ref="author2" />
        <constructor-arg index="1" value="It" />
    </bean>

    <!-- A Book created referring to author3 (created above) via
         a property setter -->
    <bean id="book1" class="org.springframework.example.Book">
        <property name="author" ref="author3" />
        <property name="title" value="A Game of Thrones" />
    </bean>
</beans>

// The classes that are being initialized and wired above...
class Book { // assume package org.springframework.example
    Author author;
    String title;
    
    Book() {} // default constructor
    Book(Author author, String title) {
        this.author = author;
        this.title= title;
    }

    Author getAuthor() { return author; }
    String getTitle() { return title; }

    void setAuthor(Author author) {
        this.author = author;
    }

    void setTitle(String title) {
        this.title= title;
    }
}

class Author { // assume package org.springframework.example
    String firstName;
    String lastName;

    Author() {} // default constructor
    Author(String firstName, String lastName) {
        this.firstName = firstName;
        this.lastName = lastName;
    }

    String getFirstName() { return firstName; }
    String getLastName() { return lastName; }

    void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    void setLastName(String lastName) {
        this.lastName = lastName;
    }
}

オートワイヤリング

オートワイヤリングは、クラスがで豆であることを行っているかを指定するsterotypeアノテーションを使用して行われるApplicationContext 、および使用AutowiredとValue豆の依存関係を指定するために注釈を。 autowiringの独特な部分は、Bean自体のクラス内ですべて行われるため、外部ApplicationContext定義がないことです。

@Component // The annotation that specifies to include this as a bean
           // in the ApplicationContext
class Book {
    
    @Autowired // The annotation that wires the below defined Author
               // instance into this bean
    Author author;

    String title = "It";

    Author getAuthor() { return author; }
    String getTitle() { return title; }
}

@Component // The annotation that specifies to include
           // this as a bean in the ApplicationContext
class Author {
    String firstName = "Steven";
    String lastName = "King";

    String getFirstName() { return firstName; }
    String getLastName() { return lastName; }
}

ApplicationContextのブートストラップ

Java Config

構成クラスは、アプリケーションのクラスパス上にあり、アプリケーションのメインクラスに見えるクラスである必要があります。

class MyApp {
    public static void main(String[] args) throws Exception {
        AnnotationConfigApplicationContext appContext =
            new AnnotationConfigApplicationContext(MyConfig.class);
        
        // ready to retrieve beans from appContext, such as myObject.
    }
}

@Configuration
class MyConfig {
    @Bean
    MyObject myObject() {
        // ...configure myObject...
    }

    // ...define more beans...
}

Xml構成

構成XMLファイルは、アプリケーションのクラスパス上にある必要があります。

class MyApp {
    public static void main(String[] args) throws Exception {
        ClassPathXmlApplicationContext appContext =
            new ClassPathXmlApplicationContext("applicationContext.xml");
        
        // ready to retrieve beans from appContext, such as myObject.
    }
}

<?xml version="1.0" encoding="UTF-8"?>
<!-- applicationContext.xml -->
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
                        http://www.springframework.org/schema/beans/spring-beans.xsd">
    <bean id="myObject" class="com.example.MyObject">
        <!-- ...configure myObject... -->
    </bean>

    <!-- ...define more beans... -->
</beans>

オートワイヤリング

オートワイヤリングでは、アノテーション付きBean（ @Component ）をスキャンする基本パッケージを知る必要があります。これは#scan(String...)メソッドで指定します。

class MyApp {
    public static void main(String[] args) throws Exception {
        AnnotationConfigApplicationContext appContext =
            new AnnotationConfigApplicationContext();
        appContext.scan("com.example");
        appContext.refresh();
        
        // ready to retrieve beans from appContext, such as myObject.
    }
}

// assume this class is in the com.example package.
@Component
class MyObject {
    // ...myObject definition...
}