Spring注解驱动开发

Spring注解驱动开发

组件注册-@Configuration&@Bean给容器中注册组件

修改pom文件

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.atguigu</groupId>
  <artifactId>spring-annotation</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  
  <dependencies>
  	<dependency>
	    <groupId>org.springframework</groupId>
	    <artifactId>spring-context</artifactId>
	    <version>4.3.12.RELEASE</version>
	</dependency>
  </dependencies>
</project>

如果

创建一个实体类

package com.atguigu.bean;

public class Person {
	private String name;
	private Integer age;
	
	public Person() {
		super();
	}
	
	public Person(String name, Integer age) {
		super();
		this.name = name;
		this.age = age;
	}
	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;
	}
	@Override
	public String toString() {
		return "Person [name=" + name + ", age=" + age + "]";
	}
}

以前的xml方式

<?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.atguigu.bean.Person">
		<property name="age" value="18"></property>
		<property name="name" value="zhangsan"></property>
	</bean>
	

</beans>

package com.atguigu;

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

import com.atguigu.bean.Person;
import com.atguigu.config.MainConfig;

public class MainTest {

	@SuppressWarnings("resource")
	public static void main(String[] args) {
		ApplicationContext applicationContext = new ClassPathXmlApplicationContext("beans.xml");
		Person person = (Person)applicationContext.getBean("person");
		System.out.println(person);
	}
}

@Bean注解方式

package com.atguigu.config;

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

import com.atguigu.bean.Person;

/**
 * 配置类
 * 等同于以前的配置文件
 */
@Configuration  //告诉Spring这是一个配置类
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
	public Person person() {
		return new Person("lisi",20);
	}
	
}

package com.atguigu;

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

import com.atguigu.bean.Person;
import com.atguigu.config.MainConfig;

public class MainTest {

	public static void main(String[] args) {
//		ApplicationContext applicationContext = new ClassPathXmlApplicationContext("beans.xml");
//		Person person = (Person)applicationContext.getBean("person");
//		System.out.println(person);
		ApplicationContext applicationContext = new AnnotationConfigApplicationContext(MainConfig.class);
		Person person = applicationContext.getBean(Person.class);
		System.out.println(person);
	}
	
}

@Bean（“person02”） 还可以为Bean的类型名取名

来源：CSDN

作者：等我下课

链接：https://blog.csdn.net/qq_41911570/article/details/104074248