java 配置在.properties文件中的常量

不讓用常量類，那就用.properties文件配置，放在根目錄。

 

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Properties;

/**
 * Created by syl on 2017/12/12 0007. 讀取常量properties文件
 */
public class PropertyUtil {  
    @SuppressWarnings("rawtypes")
    private static Map map = null;  
  
    @SuppressWarnings({ "rawtypes", "unchecked" })
    private static void loadFile() {  
        map = new HashMap();  
        try {  
            Properties p = new Properties();  
            p.load(PropertyUtil.class.getClassLoader().getResourceAsStream("params.properties"));  
            Iterator it = p.keySet().iterator();  
            while (it.hasNext()) {  
                String key = (String) it.next();  
                String value = p.getProperty(key);  
                map.put(key, value);  
            }  
        } catch (Exception e) {  
            e.printStackTrace();  
        }  
    }  
  
    public static String getValue(String str) {  
        if (map == null) {  
            loadFile();  
        }  
        return (String) map.get(str);  
    }  
    
    public static void main(String[] args) {
        String s = PropertyUtil.getValue("test");
        System.out.println(s);
    }
}

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