加载properties文件的三种方法

源代码：

package a.one;

import java.io.FileInputStream;
import java.io.InputStream;
import java.util.Properties;

public class Test1 {
/*    private static String driver;
    private static String url;
    private static String user;
    private static String password;*/
    
    
    
    //利用反射加载properties文件
    public static void main(String[] args) throws Exception {
        //
        Properties p=new Properties();
        FileInputStream in=new FileInputStream("config/c.properties");
        p.load(in);
        System.out.println(p);
        System.out.println("name:"+p.getProperty("name"));
        System.out.println("============使用类加载器加载properties文件=============");
        InputStream in2=Test1.class.getClassLoader().getResourceAsStream("db.properties");
        Properties p2=new Properties();
        p2.load(in2);
        System.out.println(p2);
        System.out.println("password:"+p2.getProperty("password"));
        System.out.println("============直接用类文件加载，其实里面就是封装了getClassLoader()方法==============");
        InputStream in3=Test1.class.getResourceAsStream("/db.properties");
        Properties p3=new Properties();
        p3.load(in3);
        System.out.println(p3);
        System.out.println("user:"+p3.getProperty("user"));
    }
}

配置文件db.properties在src下

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/mydb3
user=root
password=123456

结果：

{age=30, name=taeyeon, song=four seasons}
name:taeyeon
============使用类加载器加载properties文件=============
{user=root, password=123456, url=jdbc:mysql://localhost:3306/mydb3, driver=com.mysql.jdbc.Driver}
password:123456
============直接用类文件加载，其实里面就是封装了getClassLoader()方法==============
{user=root, password=123456, url=jdbc:mysql://localhost:3306/mydb3, driver=com.mysql.jdbc.Driver}
user:root