PropertyPlaceholderConfigurer类重构

  

  在使用Spring框架的项目中，通过代码直接读取properties配置项不方便。为了更好读取，继承PropertyPlaceholderConfigurer类，重写processProperties()方法，将加载到Spring框架中的配置项缓存到一个Map中，同时对外提供接口方法进行调用，以达到目的，具体实现如下：

1、定义接口PropertiesConfig及方法 

import java.util.Properties;

public interface PropertiesConfig {

    String getValue(String key);

    String getValue(String key, String defaultValue);

    Properties getGroupProperties(String preFix, boolean retContainPrefix);

    // TODO 可 定义任意和properties相关的方法
}

2、继承PropertyPlaceholderConfigurer类，重写processProperties()方法，并实现PropertiesConfig接口

import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Properties;
import java.util.Set;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.config.PropertyPlaceholderConfigurer;
import org.springframework.util.PropertyPlaceholderHelper;

public class DefaultPropertyPlaceholderConfigurer extends PropertyPlaceholderConfigurer implements PropertiesConfig {

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

    @Override
    protected void processProperties(ConfigurableListableBeanFactory beanFactoryToProcess, Properties props)
            throws BeansException {
        super.processProperties(beanFactoryToProcess, props);
        try {
            PropertyPlaceholderHelper helper = new PropertyPlaceholderHelper(DEFAULT_PLACEHOLDER_PREFIX,
                    DEFAULT_PLACEHOLDER_SUFFIX, DEFAULT_VALUE_SEPARATOR, false);
            Set<Entry<Object, Object>> pSet = props.entrySet();
            String key = null;
            String val = null;
            for (Entry<Object, Object> entry : pSet) {
                key = String.valueOf(entry.getKey());
                val = String.valueOf(entry.getValue());
                // 占位符替换为真实值
                val = helper.replacePlaceholders(val, props);

                // TODO 可做任意相关的处理，比如密码加解密等
                String lKey = key.toLowerCase();
                if (lKey.contains("pwd") || lKey.contains("password") || lKey.contains("passwd")
                        || lKey.contains("passw")) {
                    System.out.println("key:" + key + ",value:******");
                } else {
                    System.out.println("key:" + key + ",value:" + val);
                }
                pMap.put(key, val);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public String getValue(String key) {
        return pMap.get(key);
    }

    public String getValue(String key, String defaultValue) {
        String val = getValue(key);
        if (val == null) {
            return defaultValue;
        }
        return val;
    }

    public Properties getGroupProperties(String preFix, boolean retContainPrefix) {
        Properties pp = new Properties();
        if (preFix == null || preFix.trim().equals("")) {
            pp.putAll(pMap);
            return pp;
        }

        Set<Entry<String, String>> es = pMap.entrySet();
        String key = null;
        for (Entry<String, String> e : es) {
            key = e.getKey();
            if (key.startsWith(preFix)) {
                if (retContainPrefix) {
                    pp.put(key, e.getValue());
                } else {
                    pp.put(key.replaceFirst(preFix, ""), e.getValue());
                }
            }
        }
        return pp;
    }
}

3、修改spring的bean配置文件

  找到spring content的XML文件，将如下的修改为红色部分：

<!--<bean id="propertyConfigurer"

class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"> -->

<bean id="propertyConfigurer"

class="org.slive.spring.configurer.DefaultPropertyPlaceholderConfigurer">

<property name="locations">

<list>

<value>classpath:conf/xxx1.properties </value>

<value>classpath:conf/xxx2.properties </value>

</list>

</property>

</bean>

4、使用ProertiesConfig接口方法

(1) 任意bean类中注入

@Autowired

private ProertiesConfig config;

(2) 或者非bean类中，假设你项目中又一个SpringBeanUtil类

private ProertiesConfig config =

SpringBeanUtil.getBean(ProertiesConfig.class);