Spring入门（8）-基于Java配置而不是XML
本文介绍如何应用Java配置而不是通过XML配置Spring。
0. 目录
- 声明一个简单Bean
- 声明一个复杂Bean
1. 声明一个简单Bean
还是需要简单的XML配置的，如下：
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd"
>
<context:component-scan base-package="com.chzhao.springtest"/>
</beans>
声明一个配置类
package com.chzhao.springtest;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
public class MyConfig {
@Bean
public App app1() {
return new App();
}
}
通过@Configuration声明配置类，通过@Bean声明Bean。其中app1就是Bean的ID。
可以通过这个app1值机获得Bean
package com.chzhao.springtest;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class Main {
public static void main(String[] args) {
@SuppressWarnings("resource")
ApplicationContext act = new ClassPathXmlApplicationContext(
"applicationContext.xml");
App a = (App) act.getBean("app1");
a.showMsg();
}
}
2. 声明一个复杂Bean
如果一个Bean的定义基于另外一个Bean，也很容易实现。
首先看app定义
package com.chzhao.springtest;
public class App {
public App(IPersonBll personBll) {
this.personBll = personBll;
}
private IPersonBll personBll;
public void showMsg() {
this.personBll.show();
}
}
package com.chzhao.springtest;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
public class MyConfig {
@Bean
public IPersonBll bll1() {
return new PersonBll();
}
@Bean
public App app1() {
return new App(bll1());
}
}