java - 使用 Spring : 需要澄清

Question

我正在学习spring标签的使用。我写了一个简单的程序。

    <bean id="book" class="com.test.scoped.Book" scope="prototype" >
    <property name="name" value="DefaultName"></property>
         <aop:scoped-proxy/> 
    </bean>

    <bean id="reader" class="com.test.scoped.Reader" >
        <property name="book" ref="book" />
    </bean>


public class Book {

    private String name;

    public String toString (){
        return this.name;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

}


class Reader {
    private Book book;

    public Book getBook() {
        return book;
    }

    public void setBook(Book book) {
        this.book = book;
    }

}


    public static void main(String[] args) {
        // TODO Auto-generated method stub

        ApplicationContext ctx = new ClassPathXmlApplicationContext("ScopedProxy.xml");

        Book firstBook  = ((Reader)ctx.getBean("reader")).getBook();
        System.out.println("First Book : "+firstBook.getName());
        firstBook.setName("Edge of Eternity");
        System.out.println("First Book : "+firstBook.getName());

        Book secondBook = ((Reader)ctx.getBean("reader")).getBook();
        System.out.println("Second Book : "+secondBook.getName());
    }

}

When I run Main class , I get below result :

First Book : DefaultName

First Book : DefaultName

Second Book : DefaultName

My Question, why is name of the firstBook not set even though I have set it : firstBook.setName("Edge of Eternity"); . When I remove aop:scoped-proxy , name is set properly. Why is default name not overwrritten ?

Answer 1

您不应该按照您现在的方式使用作用域代理 bean。范围代理 bean 在开发 - 即 - web 应用程序并将它们用作从单例 bean 引用时非常有用。

查看 Spring 文档 [1]:“您不需要将 与作用域为单例或原型(prototype)的 bean 结合使用”

[1] http://docs.spring.io/spring/docs/current/spring-framework-reference/html/beans.html#beans-factory-scopes-other-injection