获取位于WebContent/file文件夹下的address.properties文件的内容的三种方式

package com.yxfyg.servlet;

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

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class Servlet03 extends HttpServlet{

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        ServletContext context = getServletContext();
        Properties properties = new Properties();
        InputStream is = null;
        //读取配置文件的三种方法（注意第三种方式相对路径相对的参照物和一二两种方式不同）
        //第一种：通过ServletContext对象的getRealPath方法获取配置文件在Tomcat中的真实路径，然后转化为InputStream流
        //String path = context.getRealPath("file/address.properties");
        //is = new FileInputStream(path);
        //第二种：通过ServletContext对象的getResourceAsStream方法直接将配置文件转化为流
        //is = context.getResourceAsStream("file/address.properties");
        //第三种：通过类加载器将配置文件转化为流
        is = this.getClass().getClassLoader().getResourceAsStream("../../file/address.properties");
        properties.load(is);
        String address = properties.getProperty("address");
        System.out.println("address:" + address);
    }
    
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
    
}