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);
     }
 }