关于replacePlaceholders

现在还没有完全验证好，有空看看报错信息

https://www.cnblogs.com/fanguangdexiaoyuer/p/5788432.html

1.目录结构

　　

2.

package cn.caojun.properties;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.config.PropertyPlaceholderConfigurer;
import org.springframework.util.PropertyPlaceholderHelper;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties;

public class CustomPropertyConfigurer extends PropertyPlaceholderConfigurer {
    private static Map<String,String> properties = new HashMap<String,String>();
    protected void processProperties(ConfigurableListableBeanFactory beanFactoryToProcess, Properties props) throws BeansException {
    // cache the properties
        PropertyPlaceholderHelper helper = new PropertyPlaceholderHelper(
                DEFAULT_PLACEHOLDER_PREFIX, DEFAULT_PLACEHOLDER_SUFFIX, DEFAULT_VALUE_SEPARATOR, false);
        for(Map.Entry<Object,Object> entry:props.entrySet()){
             String stringKey = String.valueOf(entry.getKey());
             String stringValue = String.valueOf(entry.getValue());
             //用属性文件键值属性props替换字符串stringValue
             stringValue = helper.replacePlaceholders(stringValue, props);
             properties.put(stringKey, stringValue);
         }
        super.processProperties(beanFactoryToProcess, props);
    }

    public static Map<String, String> getProperties() {
        return properties;
    }

    public static String getProperty(String key){
        return properties.get(key);
    }
}

3.property

site=iteye
blog=antlove
url=${site}/${blog}

4.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"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
    <bean id="SpringDemo" class="cn.caojun.spring.SpringDemo"></bean>
    <bean id="propertyConfigurer" class="cn.caojun.properties.CustomPropertyConfigurer">
        <property name="locations">
            <list>
                <value>classpath:cn/caojun/properties/project.properties</value>
            </list>
        </property>
    </bean>
</beans>

5.Main

package cn.caojun.properties;

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

import java.util.Map;

public class Main {
    public static void main(String[] args) {
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("classpath:spring/applicationContext.xml");
        CustomPropertyConfigurer customPropertyConfigurer=(CustomPropertyConfigurer)applicationContext.getBean("propertyConfigurer");
        Map<String,String> properties = customPropertyConfigurer.getProperties();
        System.out.println(properties);
    }
}