使用Spring动态加载属性文件 [英] Dynamically loading properties file using Spring

问题描述

我编写了一个PropertyUtils类（来自互联网），它将加载属性

I have written a PropertyUtils class (from internet), which will load the Properties

<bean id="propertiesUtil" class="com.myApp.PropertiesUtil" >
    <property name="locations">
        <list>
            <value>classpath:myApp/myApp.properties</value>         
        </list>
    </property>
</bean>

和一个PropertiesUtil类如下所示

and a PropertiesUtil class is like below

public class PropertiesUtil extends PropertyPlaceholderConfigurer {

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

    @Override
    protected void loadProperties(final Properties props) throws IOException {
        super.loadProperties(props);
        for (final Object key : props.keySet()) {
            properties.put((String) key, props.getProperty((String) key));
        }
    }

    public String getProperty(final String name) {
        return properties.get(name);
    }

}

后来，我可以获得物业通过调用PropertiesUtil.getProperty（）方法。

Later, I can get the property by calling PropertiesUtil.getProperty() method.

但现在我想略微修改它，如果myApp.properties被用户修改/更改，它应该是再次加载

But now I want to modify it slightly such that, If the myApp.properties get modified/changed by user, it should be loaded again

可能我需要FileWatcher类

Probably I need FileWatcher class

public abstract class FileWatcher extends TimerTask {
    private long timeStamp;
    private File file;

    public FileWatcher(File file) {
        this.file = file;
        this.timeStamp = file.lastModified();
    }

    @Override
    public final void run() {
        long timeStampNew = this.file.lastModified();

        if (this.timeStamp != timeStampNew) {
            this.timeStamp = timeStampNew;
            onChange(this.file);
        }
    }

    protected abstract void onChange(File newFile);
}

但我怀疑是

1. 如何使用类路径创建File对象：myApp / myApp.properties
   （因为绝对路径未知）


2. 我如何调用/调用spring到
   加载/将新的myApp.properties传递给PropetisUtil类[在
   onChange方法中]。

推荐答案

您可以使用Spring的ReloadableResourceBundleMessageSource类，如下所示：

You can use Spring's ReloadableResourceBundleMessageSource class like below:

<?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-3.1.xsd">

    <bean id="myProperties" class="org.springframework.context.support.ReloadableResourceBundleMessageSource">
        <!-- check property file(s) every 1 second -->
        <property name="cacheSeconds" value="1"/>
        <property name="basenames">
            <list>
                <value>myApp/myApp</value>
            </list>
        </property>
    </bean>

</beans>

然后你可以调用MessageSource.getMessage（）方法来获取属性值。这是一个例子：

And then you can call MessageSource.getMessage() method to get the property value. Here is an example:

package com.example;

import org.springframework.context.ApplicationContext;
import org.springframework.context.MessageSource;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class MyApp {
public static void main(String[] args) throws InterruptedException {
        ApplicationContext ctx = new ClassPathXmlApplicationContext("myApp/MyApp.xml");
        MessageSource myProperties = (MessageSource) ctx.getBean("myProperties");
        while (true) {
            System.out.println(myProperties.getMessage("myApp.propertyOne", null, null));
            Thread.sleep(1000);
        }
    }
} 

您可以直接调用ApplicationContext。 getMessage（字符串代码，Object [] args，Locale语言环境）如果你将'myProperties'bean重命名为'messageSource'。

You can directly call ApplicationContext.getMessage(String code, Object[] args, Locale locale) if you renamed your 'myProperties' bean as 'messageSource'.

对于你的网络应用程序，请把你的属性Web应用程序类路径之外的文件（因为Web服务器可能会缓存它们）。例如，WEB-INF / conf / myApp.properties

For your web apps, please put your property files outside of your web app's classpath (because the web server might cache them). For instance, WEB-INF/conf/myApp.properties

这篇关于使用Spring动态加载属性文件的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！