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javaConfig是什么

news 来源：原创 2024/5/1 14:04:00

先放个从xml转到javaConfig的例子：

xml：

    <?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-3.2.xsd">   
 
        <bean id="button" class="javax.swing.JButton">   
            <constructor-arg value="Hello World" />   
        </bean>   
 
        <bean id="anotherButton" class="javax.swing.JButton">   
            <property name="icon" ref="icon" />   
        </bean>   
 
        <bean id="icon" class="javax.swing.ImageIcon">   
            <constructor-arg>   
                <bean class="java.net.URL">   
                  <constructor-arg value="http://morevaadin.com/assets/images/learning_vaadin_cover.png" />   
                </bean>   
            </constructor-arg>   
        </bean>   
    </beans>

javaConfig：

    import java.net.MalformedURLException;  
    import java.net.URL;  
    import javax.swing.Icon;  
    import javax.swing.ImageIcon;  
    import javax.swing.JButton;  
    import org.springframework.context.annotation.Bean;  
    import org.springframework.context.annotation.Configuration;  
 
    @Configuration  
    public class MigratedConfiguration {  
        @Bean  
        public JButton button() {  
            return new JButton("Hello World");  
        }  
 
        @Bean  
        public JButton anotherButton(Icon icon) {  
            return new JButton(icon);  
        }  
 
        @Bean  
        public Icon icon() throws MalformedURLException {  
            URL url = new URL(  
                    "http://morevaadin.com/assets/images/learning_vaadin_cover.png");  
            return new ImageIcon(url);  
        }  
    }

用法非常简单：

1.用@Configuration注解JavaConfig类，

2.用每个方法来表示Bean并使用@Bean注解方法。

3.每个方法名代表XML配置文件中的name

注意在Web环境中，需要在web.xml中加入如下代码：

<context-param>  
    <param-name>contextClass</param-name>  
    <param-value>org.springframework.web.context.support.AnnotationConfigWebApplicationContext</param-value>  
</context-param>  
<context-param>  
    <param-name>contextConfigLocation</param-name>  
    <param-value>com.packtpub.learnvaadin.springintegration.SpringIntegrationConfiguration</param-value>  
</context-param>