PropertiesLoader：

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.core.io.DefaultResourceLoader;
import org.springframework.core.io.Resource;
import org.springframework.core.io.ResourceLoader;

import java.io.IOException;
import java.io.InputStream;
import java.util.NoSuchElementException;
import java.util.Properties;

public class PropertiesLoader {
    private static Logger logger = LoggerFactory.getLogger(PropertiesLoader.class);
    private static ResourceLoader resourceLoader = new DefaultResourceLoader();
    private final Properties properties;

    public PropertiesLoader(String... resourcesPaths) {
        this.properties = this.loadProperties(resourcesPaths);
    }

    public Properties getProperties() {
        return this.properties;
    }

    private String getValue(String key) {
        String systemProperty = System.getProperty(key);
        if (systemProperty != null) {
            return systemProperty;
        } else {
            return this.properties.containsKey(key) ? this.properties.getProperty(key) : "";
        }
    }

    public String getProperty(String key) {
        String value = this.getValue(key);
        if (value == null) {
            throw new NoSuchElementException();
        } else {
            return value;
        }
    }

    public String getProperty(String key, String defaultValue) {
        String value = this.getValue(key);
        return value != null ? value : defaultValue;
    }

    public Integer getInteger(String key) {
        String value = this.getValue(key);
        if (value == null) {
            throw new NoSuchElementException();
        } else {
            return Integer.valueOf(value);
        }
    }

    public Integer getInteger(String key, Integer defaultValue) {
        String value = this.getValue(key);
        return value != null ? Integer.valueOf(value) : defaultValue;
    }

    public Double getDouble(String key) {
        String value = this.getValue(key);
        if (value == null) {
            throw new NoSuchElementException();
        } else {
            return Double.valueOf(value);
        }
    }

    public Double getDouble(String key, Integer defaultValue) {
        String value = this.getValue(key);
        return value != null ? Double.valueOf(value) : (double) defaultValue;
    }

    public Boolean getBoolean(String key) {
        String value = this.getValue(key);
        if (value == null) {
            throw new NoSuchElementException();
        } else {
            return Boolean.valueOf(value);
        }
    }

    public Boolean getBoolean(String key, boolean defaultValue) {
        String value = this.getValue(key);
        return value != null ? Boolean.valueOf(value) : defaultValue;
    }

    private Properties loadProperties(String... resourcesPaths) {
        Properties props = new Properties();
        String[] var3 = resourcesPaths;
        int var4 = resourcesPaths.length;

        for (int var5 = 0; var5 < var4; ++var5) {
            String location = var3[var5];
            InputStream is = null;

            try {
                Resource resource = resourceLoader.getResource(location);
                is = resource.getInputStream();
                props.load(is);
            } catch (IOException var12) {
                logger.info("Could not load properties from path:" + location + ", " + var12.getMessage());
            } finally {
                try {
                    if (is != null) {
                        is.close();
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }

        return props;
    }
}

PropertiesUtil：

import com.google.common.collect.Maps;

import java.util.Map;

public class PropertiesUtil {

    private static Map<String, String> map = Maps.newHashMap();
    private static PropertiesLoader loader = new PropertiesLoader(new String[]{"application.properties"});

    public static String getConfig(String key) {
        String value = map.get(key);
        if (value == null) {
            value = loader.getProperty(key);
            map.put(key, value != null ? value : "");
        }
        return value;
    }
}

配置文件：

静态代码块读取配置文件： 

    static {
        try {
            String participates = PropertiesUtil.getConfig("participates");
             
        } catch (Exception e) {
            LOG.error("加载配置出错:{}", e.getMessage());
        }
    }