package com.gavin.util;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.Date;
import java.util.Properties;


public class PropertiesUtil {
    private static Properties properties= new Properties();
    
    /*properties文件名*/
    private static final String PROPERTIES_FILE_NAME="setting.properties";

    
    
    /**
     * 初始化properties，即载入数据
     */
    private static void initProperties(){
        try {
            InputStream ips = PropertiesUtil.class.getClassLoader().getResourceAsStream(PROPERTIES_FILE_NAME);
            properties.load(ips);
            ips.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**将数据载入properties，并返回key的值
     * @return
     */
    public static String getPrimaryKey(String key){
        if(properties.isEmpty())//如果properties为空，则初始化一次。
            initProperties();
        return properties.getProperty(key); 
    }
    
    /**修改key的值，并保存
     * @param id
     */
    @SuppressWarnings("deprecation")
	public static void saveKeyVal(String key ,String val){
        if(properties.isEmpty())
            initProperties();
        //修改值
        properties.setProperty(key, val);
        //保存文件
        try {
            URL fileUrl = PropertiesUtil.class.getClassLoader().getResource(PROPERTIES_FILE_NAME);//得到文件路径
            FileOutputStream fos = new FileOutputStream(new File(fileUrl.toURI()));
            properties.store(fos,(new Date()).toLocaleString());
            fos.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    
    
    public static void main(String[] args) {
        System.out.println(getPrimaryKey("local_path"));
        saveKeyVal("local_path","");
        System.out.println(getPrimaryKey("local_path"));
    }
}