Java300学习笔记（18）—— Hashtable ，子类 Properties

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1 Hashtable

2 Hashtable 子类 Properties

• 读写资源配置文件
• 要求 键 和 值都是字符串；

package day04.pro;


import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Properties;

public class Demo1 {
    public static void main(String[] args) throws IOException {

        Properties pro = new Properties();

        pro.setProperty("driver","oracle.jdbc.driver.OracleDriver");
        pro.setProperty("url","jdbc:oracle:thin:@localhost");
        pro.setProperty("pwd","111111");

        String url = pro.getProperty("url","null");
        System.out.println(url);

        /*
        * 使用 Properties 输出到文件
        * */
        pro.store(new FileOutputStream(new File("D:/DB.properties")),"DB配置文件");
        pro.storeToXML(new FileOutputStream(new File("D:/DB.xml")),"DB-XML配置");

    }
}

2.1 类路径加载资源配置文件

• 类.class.getResourceAsStream("/")
• Thread.currentThread().getContextClassLoader().getResourceAsStream()
  

package day04.pro;


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

public class Demo2 {
    public static void main(String[] args) throws IOException {
        Properties pro = new Properties();


        //类的相对路径
       // pro.load(Demo2.class.getResourceAsStream("DB.properties"));

        pro.load(Thread.currentThread().getContextClassLoader().getResourceAsStream("DB.properties"));

        System.out.println(pro.getProperty("url","null"));
    }
}