java之spring註解開發

時間 2019-12-27

標籤 java spring 註解開發欄目 Java 简体版

原文原文鏈接

一、xml形式java

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);
    }
}

運行結果以下：spring

二、註解形式app

/**
 * 配置類==配置文件
 *
 * @Configuration 告訴Spring這是一個配置類
 * @Bean 給容器中註冊一個Bean，類型爲返回值類型，id默認是方法名做爲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、註解形式
        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、包掃描@ComponentScanide

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

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

測試類測試

public class IOCTest {

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

增長組件標記this

輸出結果：3d

源碼解析：xml

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

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