java 操作properties文件

import org.apache.commons.lang3.StringUtils;

import java.io.*;
import java.util.Enumeration;
import java.util.Properties;

public class PropertiesUtil {
	public static final Properties properties = new Properties();
	public static final String path = PropertiesUtil.class.getResource("/application.properties").getFile();
	public PropertiesUtil() throws FileNotFoundException {
		//转换成流
		InputStream inputStream = new FileInputStream(path);
		try {
			//从输入流中读取属性列表（键和元素对）
			properties.load(inputStream);
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

/**
 * 通过key获取value
 * @param key
 * @return
 */
public  String get(String key) {
    return properties.getProperty(key);
}
/**
 * 修改或者新增key
 * @param key
 * @param value
 */
public  void update(String key, String value) {
    FileOutputStream oFile = null;
    try {
        if (StringUtils.isNotEmpty(get(key))){
            delete(key);
        }
        properties.setProperty(key, value);

        oFile = new FileOutputStream(path);

        //将Properties中的属性列表（键和元素对）写入输出流
        properties.store(oFile, "");
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        try {
            oFile.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}
/**
 * 通过key删除value
 * @param key
 */
public  void delete(String key) {
    properties.remove(key);
    FileOutputStream oFile = null;
    try {
        oFile = new FileOutputStream(path);
        properties.store(oFile, "");
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        try {
            oFile.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}
/**
 * 循环所有key value
 */
public  void list() {
    Enumeration en = properties.propertyNames(); //得到配置文件的名字
    while(en.hasMoreElements()) {
        String strKey = (String) en.nextElement();
        String strValue = properties.getProperty(strKey);
        System.out.println(strKey + "=" + strValue);
    }
}