Java基础 Properties类的基本使用

package cn.chenfeng.properties;

import java.io.*;
import java.util.Iterator;
import java.util.List;
import java.util.Properties;
import java.util.Set;

public class ReadProp {
    public static void main(String[] args) throws IOException {

        File file = new File("src/application.properties");
        Properties props = new Properties();
        FileInputStream iFile = new FileInputStream(file);
        props.load(iFile);

        /**
         * 在知道key值的情况下，用getProperties()可以获取value;
         */
        String host = props.getProperty("HOST");
        System.out.println(host);

        /**
         * 不知道key的时候遍历配置文件，迭代器遍历
         */

        Iterator<String> iterator = props.stringPropertyNames().iterator();
        while (iterator.hasNext()) {
            String key = iterator.next();
//            System.out.println(key + ":" + props.getProperty(key));
        }

        /**
         * Set集合遍历
         */
        Set<String> keySet = props.stringPropertyNames();
        for (String temp : keySet
        ) {
            System.out.println(temp);
        }

        System.out.println(System.getProperty("user.dir"));
        

        iFile.close();
    }
}