JavaConfig 使用Java代码进行显示配置

从Spring 3起，JavaConfig功能已经包含在Spring核心模块，它允许开发者将bean定义和在Spring配置XML文件到Java类中。

需要先加载spring-context 包

   <!-- https://mvnrepository.com/artifact/org.springframework/spring-context -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>4.3.6.RELEASE</version>
    </dependency>

代码：

package com.company;

/**
 * Created by Administrator on 2017/2/22 0022.
 */
public interface ISay {
    void say(String msg);
}

 

package com.company;

/**
 * Created by Administrator on 2017/2/22 0022.
 */
public class SayImpl implements com.company.ISay {
    public void say(String msg){
        System.out.println("Person Say:"+msg);
    }
}

使用 @Configuration 注释告诉 Spring，这是核心的 Spring 配置文件，并通过 @Bean 定义 bean。

package com.company;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

/**
 * Created by Administrator on 2017/2/22 0022.
 */
@Configuration
public class JavaConfig {
    @Bean(name="GetSay")
    public com.company.ISay GetSay(){
        return new com.company.SayImpl();
    }
}

 

package com.company;


import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class Main {
    public static void main(String[] args)   {
        ApplicationContext context =new AnnotationConfigApplicationContext(com.company.JavaConfig.class);
        com.company.ISay obj=(com.company.ISay) context.getBean("GetSay");
        obj.say("hongdada");
    }
}

 

log4j:WARN No appenders could be found for logger (org.springframework.core.env.StandardEnvironment).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
Person Say:hongdada

 多个Bean

package com.company;


import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

interface ISay {
    String Country="China";
    void say(String msg);
}

class SayImpl implements com.company.ISay {
    public void say(String msg){
        System.out.println("Person Say:"+msg);
    }
}


class SayImpl2 implements com.company.ISay {
    public void say(String msg){
        System.out.println(com.company.ISay.Country+" Person2  Say:"+msg);
    }
}

@Configuration
class JavaConfig {
    @Bean(name="GetSay")
    public com.company.ISay GetSay(){
        return new com.company.SayImpl();
    }

    @Bean(name="GetSay2")
    public com.company.ISay GetSayTwo(){
        return new com.company.SayImpl2();
    }
}

public class Main {
    public static void main(String[] args)   {
        ApplicationContext context =new AnnotationConfigApplicationContext(com.company.JavaConfig.class);
        com.company.ISay obj=(com.company.ISay) context.getBean("GetSay");
        obj.say("hongdada");

        com.company.ISay obj2=(com.company.ISay) context.getBean("GetSay2");
        obj2.say("hongdada");
    }
}

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