工具类

package com.wanggs.pay.payutil;

/**
 * Created by Wgs on 2017/9/3.
 */

import org.springframework.beans.factory.config.PropertyPlaceholderConfigurer;

import java.util.HashMap;
import java.util.Map;

/**
 * 扩展PropertyPlaceholderConfigurer,方便读取属性<br>
 * 使用方法:
 * <pre>
 * {@literal
 * <!-- spring的属性加载器，加载properties文件中的属性 -->
 * <bean id="propertyConfigurer"
 * class="component.common.utils.PropertyUtil">
 * <property name="location">
 * <value>classpath:/config.properties</value>
 * </property>
 * </bean>
 *
 * 然后调用PropertyUtil.getProperty(key);即可读取属性文件中的内容了
 *
 * }
 * </pre>
 *
 * @author tanghc
 */
public class PropertyUtil
        extends PropertyPlaceholderConfigurer {

    private static Map<String, String> propertiesData = new HashMap<String, String>();

    @Override
    protected String convertProperty(String propertyName, String propertyValue) {
        String value = super.convertProperty(propertyName, propertyValue);

        propertiesData.put(propertyName, value);

        return value;
    }

    /**
     * 获取Properties文件中的值,如果不存在则返回defaultValue
     *
     * @param key
     * @param defaultValue
     * @return
     */
    public static String getProperty(String key, String defaultValue) {
        String value = propertiesData.get(key);
        return value == null ? defaultValue : value;
    }

    /**
     * 获取Properties文件中的值,不存在返回null
     *
     * @param key
     * @return
     */
    public static String getProperty(String key) {
        return getProperty(key, null);
    }

}

测试

package com.wanggs.controller;

import com.wanggs.pay.payutil.PropertyUtil;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;

/**
 * Created by Wgs on 2017/8/6.
 */
@Controller
@RequestMapping("/")
public class HelloController {
    @Value("${wx.token}")
    private String token;
    @RequestMapping("/index")
    public String index(){
        System.out.println(token);
        // PropertyPlaceholderConfigurer的用法
        String result = PropertyUtil.getProperty("wx.token");
        System.out.println(result);
        return "hello";

    }

}

springMvc 配置文件

<?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"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       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 http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <!--自动扫描@Controller-->
    <context:component-scan base-package="com.wanggs.controller">
        <context:include-filter type="annotation" expression="org.springframework.stereotype.Controller"/>
    </context:component-scan>

    <mvc:annotation-driven/>
    <mvc:default-servlet-handler/>

    <!--视图解析器-->
    <bean id="viewResolver" class="org.springframework.web.servlet.view.UrlBasedViewResolver">
        <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/>
        <property name="prefix" value="/WEB-INF/views/"/>
        <property name="suffix" value=".jsp"/>
    </bean>
    <!--通过@Value注解读取.properties配置内容-->
    <bean id="configProperties" class="org.springframework.beans.factory.config.PropertiesFactoryBean">
        <property name="locations">
            <list>
                <!--配置文件名称-->
                <value>classpath:config.properties</value>
            </list>
        </property>
    </bean>


    <!--PropertyPlaceholderConfigurer的配置-->
    <bean id="PropertyUtil" class="com.wanggs.pay.payutil.PropertyUtil">

        <property name="locations">

            <list>

                <value>classpath:config.properties</value>

            </list>

        </property>

    </bean>

</beans>