spring注解-Hello World

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使用java类代替传统的xml

传统配置

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<?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"
	xmlns:aop="http://www.springframework.org/schema/aop"
	xmlns:tx="http://www.springframework.org/schema/tx"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd
		http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.3.xsd
		http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.3.xsd">
	
	<bean id="person" class="com.yhzl.bean.Person"  scope="prototype" >
		<property name="age" value="18"></property>
		<property name="name" value="zhangsan"></property>
	</bean>

</beans>

java配置类

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//配置类==配置文件
@Configuration
public class MainConfig {
	
	//给容器中注册一个Bean;类型为返回值的类型，id默认是用方法名作为id
	@Bean("person")
	public Person person01(){
		return new Person("lisi", 20);
	}

}

实体类

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public class Person {
	private String name;
	private Integer age;
	private String nickName;
	
	public String getNickName() {
		return nickName;
	}
	public void setNickName(String nickName) {
		this.nickName = nickName;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public Integer getAge() {
		return age;
	}
	public void setAge(Integer age) {
		this.age = age;
	}
	
	public Person(String name, Integer age) {
		super();
		this.name = name;
		this.age = age;
	}
	public Person() {
		super();
		// TODO Auto-generated constructor stub
	}
	@Override
	public String toString() {
		return "Person [name=" + name + ", age=" + age + ", nickName=" + nickName + "]";
	}

测试类

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public class MainTest {
	
	public static void main(String[] args) {
// 		传统方式
//		ApplicationContext applicationContext = new ClassPathXmlApplicationContext("beans.xml");
//		Person bean = (Person) applicationContext.getBean("person");
//		System.out.println(bean);
		
		ApplicationContext applicationContext = new AnnotationConfigApplicationContext(MainConfig.class);
		Person bean = applicationContext.getBean(Person.class);
		System.out.println(bean);
		// 通过类型获取beanName
		String[] namesForType = applicationContext.getBeanNamesForType(Person.class);
		for (String name : namesForType) {
			System.out.println(name);
		}
	
	}

}

注解说明

@Configuration

告诉Spring这是一个配置类

@Bean

等同于传统xml的标签，id默认为方法名，若想改变id可给@Bean注解传入参数，如：@Bean(“person”)