Spring第九章：配置文件加载

Spring 中加载 properties 文件

　　1. 在 src 下新建 xxx.properties 文件

　　2. 在 spring 配置文件中先引入 xmlns:context,在下面添加

　　　　2.1 如果需要记载多个配置文件逗号分割

　　　　　　<context:property-placeholder location="classpath:db.properties"/>

　　3 添加注解扫描

　　　　<context:component-scan base-package="com.bjsxt.service.impl"></context:component-scan>

　　4. 在被Spring管理的类中通过@Value(“${key}”)取出properties中内容

　　5.示例代码

　　　　5.1  application

　　

<?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" >

    <!--加载配置文件可以支持,分割同时加载多个配置文件-->
    <context:property-placeholder location="classpath:db.properties"/>
    
    <!--注解扫描器-->
    <context:component-scan base-package="com.suncl"></context:component-scan>

</beans>

　　　　5.2  xx.properties

db.url=127.0.0.1/dev
db.username=zhangsan
db.pwd=1123456

　　　　5.3  实体类

package com.suncl.model;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

/**
 * Created by SCL-PC on 2019/3/5.
 */
@Component
public class DbConfig {

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

    @Value("${db.username}")
    private String username;

    @Value("${db.pwd}")
    private String pwd;

    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 getPwd() {
        return pwd;
    }

    public void setPwd(String pwd) {
        this.pwd = pwd;
    }


    @Override
    public String toString() {
        return "DbConfig{" +
                "url='" + url + '\'' +
                ", username='" + username + '\'' +
                ", pwd='" + pwd + '\'' +
                '}';
    }
}

　　　　5.4 测试类

package com.suncl.test;

import com.suncl.model.DbConfig;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

/**
 * Created by SCL-PC on 2019/2/28.
 */
public class Test {
    public static void main(String[] args) {
        ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");
        DbConfig dbConfig = (DbConfig)ac.getBean("dbConfig",DbConfig.class);
        System.out.println(dbConfig.toString());
    }
}

信息: Loading properties file from class path resource [db.properties]
DbConfig{url='127.0.0.1/dev', username='zhangsan', pwd='1123456'}

以上就是spring加载配置文件的内容。