[Spring] - Property注入

db_driverClassName=com.mysql.jdbc.Driver
db_url=jdbc:mysql://127.0.0.1/test
db_username=root
db_password=root

test_userName=Robin
test_age=18

    <bean id="configProperties" class="org.springframework.beans.factory.config.PropertiesFactoryBean">
        <property name="locations">
            <list>
                <value>classpath*:settings.properties</value>
            </list>
        </property>
    </bean>
    <bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
        <property name="ignoreResourceNotFound" value="false" />
        <property name="properties" ref="configProperties" />
    </bean>

    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="${db_driverClassName}"/>
        <property name="url" value="${db_url}" />
        <property name="username" value="${db_username}" />
        <property name="password" value="${db_password}" />
    </bean>

package com.my.common;

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

@Component
public class Settings {
    private static Settings instance;
    public static Settings getInstance() {
        return instance;
    }
    public Settings() {
        instance = this;
    }
    
    @Value("#{configProperties[‘test_userName‘]}")
    private String userName;
    @Value("#{configProperties[‘test_age‘]}")
    private int age;
    
    public String getUserName() {
        return userName;
    }
    public void setUserName(String userName) {
        this.userName = userName;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
}

Settings.getInstance().getUserName()