Spring课程 Spring入门篇 4-6 Spring bean装配之基于java的容器注解说明--@ImportResource和@Value java与properties文件交互

课程链接：

1　　　　解析

1.1　　这两个注解应用在什么地方

1.2　　应用方式

1.3　　xml方式实现取值

2　　　　代码演练

2.1　　@ImportResource和@Value代码演练

1　　　　解析

1.1　　这两个注解应用在什么地方

接口调用，java与properties文件交互获取url和用户名密码等配置信息

1.2　　应用方式

java类通过调用@Importresource找到xml，通过xml配置properties

示例：

@Configuration
@ImportResource("classpath:config.xml")
public class StoreConfig {

    @Value("${jdbc.url}")
    private String url;

    @Value("${jdbc.userName}")
    private String userName;

    @Value("${jdbc.passWord}")
    private String passWord;
}

xml配置：

<context:property-placeholder location="classpath:/config.properties" ignore-unresolvable="true"/>

config.properties配置：

jdbc.url = 127.0.0.1
jdbc.userName = root
jdbc.passWord = root

1.3　　xml方式实现取值

<context:property-placeholder location="classpath:/config.properties" ignore-unresolvable="true"/>

<bean class="com.ddwei">
    <property name="url" value="${jdbc.url}"/>
    <property name="username" value="${jdbc.username}"/>
    <property name="password" value="${jdbc.password}"/>
</bean>

2　　　　代码演练

2.1　　@ImportResource和@Value代码演练

测试类：

package com.imooc.test.beanannotation;

import org.junit.Test;

import com.imooc.beanannotation.javabased.MyDriverManager;
import com.imooc.test.base.UnitTestBase;

public class TestJavaBased extends UnitTestBase{

    public TestJavaBased(){
        super("classpath*:spring-beanannotation.xml");
    }

    @Test
    public void testStoreConfig(){
        System.out.println(super.getbean("store").getClass().getName());
    }

    @Test
    public void testMyDriverStore(){
        MyDriverManager myDriverStore =super.getbean("myDriverStore");
        System.out.println(myDriverStore.getClass().getName());
    }

}

实体类：

package com.imooc.beanannotation.javabased;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.ImportResource;

@Configuration
@ImportResource("classpath:config.xml")
public class StoreConfig {

    @Value("${jdbc.url}")
    private String url;

    @Value("${jdbc.userName}")
    private String userName;

    @Value("${jdbc.passWord}")
    private String passWord;

    public String getUrl() {
        return url;
    }

    public void setUrl(String url) {
        this.url = url;
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public String getPassWord() {
        return passWord;
    }

    public void setPassWord(String passWord) {
        this.passWord = passWord;
    }

//    @Bean(name="store",initMethod="init",destroyMethod="destroy")
//    public Store getStringStore(){
//        return new StringStore();
//    }

    /**
     * 此处作为实体类：
     * 通过@bean将myDriverStore注解到spring容器中，供TestJavaBased调用
     * @return
     */
    @Bean
    public MyDriverManager myDriverStore() {
        return new MyDriverManager(url, userName, passWord);
    }

}

关联类:

package com.imooc.beanannotation.javabased;

/**
 * 测试基类
 * 被StoreConfig 以bean注解的方式引入
 * @author weijingli
 *
 */
public class MyDriverManager {

    /**
     * 有参构造方法，被StoreConfig调用
     * @param url
     * @param userName
     * @param passWord
     */
    public MyDriverManager(String url,String userName,String passWord) {
        System.out.println("This url is "+url);
        System.out.println("This userName is "+userName);
        System.out.println("This url passWord "+passWord);
    }

}

config.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"
xmlns:context="http://www.springframework.org/schema/context"
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.xsd">

<context:property-placeholder location="classpath:/config.properties" ignore-unresolvable="true"/>

</beans>

config.properties:

jdbc.url = 127.0.0.1
jdbc.userName = root
jdbc.passWord = root

spring-beanannotation.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"
xmlns:context="http://www.springframework.org/schema/context"
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.xsd">

<context:component-scan base-package="com.imooc.beanannotation"></context:component-scan>

</beans>

打印结果：

三月 30, 2019 5:49:45 下午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@789df61d: startup date [Sat Mar 30 17:49:45 CST 2019]; root of context hierarchy
三月 30, 2019 5:49:45 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from URL [file:/F:/xiangmu3/Xin/FuQiang/Spring/ddwei-dao/target/classes/spring-beanannotation.xml]
三月 30, 2019 5:49:46 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from class path resource [config.xml]
This url is 127.0.0.1
This userName is root
This url passWord root
com.imooc.beanannotation.javabased.MyDriverManager
三月 30, 2019 5:49:47 下午 org.springframework.context.support.ClassPathXmlApplicationContext doClose
信息: Closing org.springframework.context.support.ClassPathXmlApplicationContext@789df61d: startup date [Sat Mar 30 17:49:45 CST 2019]; root of context hierarchy