java之spring注解开发

一、xml形式

Person.java

package com.jackhu.bean;

public class Person {

    private String name;
    private int age;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    @Override
    public String toString() {
        return "com.jackhu.bean.Person{" +
                "name='" + name + '\'' +
                ", age=" + age +
                '}';
    }

    public Person(String name, int age) {
        super();
        this.name = name;
        this.age = age;
    }

    public Person() {

    }
}

beans.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.xsd">

    <bean id="person" class="com.jackhu.bean.Person">
        <property name="name" value="zh"/>
        <property name="age" value="18"/>
    </bean>
</beans>

MainTest.java

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);
    }
}

运行结果以下：

 

二、注解形式

/**
 * 配置类==配置文件
 *
 * @Configuration 告诉Spring这是一个配置类
 * @Bean 给容器中注册一个Bean，类型为返回值类型，id默认是方法名做为id
 */
@Configuration
public class MainConfig {

    @Bean("person")
    public Person person2() {
        return new Person("JACK", 18);
    }
}

public class MainTest {
    public static void main(String[] args) {

        // 一、xml形式
//        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("beans.xml");
//        Person person = (Person) applicationContext.getBean("person");
//        System.out.println(person);


        // 二、注解形式
        ApplicationContext applicationContext = new AnnotationConfigApplicationContext(MainConfig.class);
        Person person = applicationContext.getBean(Person.class);
        System.out.println(person);

        String[] namesForType = applicationContext.getBeanNamesForType(Person.class);
        for (String name : namesForType) {
            System.out.println(name);
        }
    }
}

 

三、包扫描@ComponentScan

 

@Configuration
@ComponentScan(value = "com.jackhu")
public class MainConfig {

    @Bean("person")
    public Person person2() {
        return new Person("JACK", 18);
    }
}

 

测试类

public class IOCTest {

    @Test
    public void main() {
        AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext(MainConfig.class);
        // 容器中全部bean名称
        String[] names = applicationContext.getBeanDefinitionNames();
        for (String name : names) {
            System.out.println(name);
        }
    }
}

增长组件标记

输出结果：

 

源码解析：

 

 

@Configuration
@ComponentScan(value = "com.jackhu", excludeFilters = {
        @ComponentScan.Filter(type = FilterType.ANNOTATION, classes = {Controller.class, Service.class}) // excludeFilters排除 Controller和Service注解不加进来
})
public class MainConfig {

    @Bean("person")
    public Person person2() {
        return new Person("JACK", 18);
    }
}

includeFilters同理