JavaWeb学习-Servlet系列-9-ServletContext获取资源绝对路径

野性酷女 2022-02-02 03:13 256阅读 0赞

继续来学习ServletContext对象的第三个功能，就是获取当前应用项目下的任何资源文件的绝对路径，这里我们模拟在不同路径下写三个properties文件，分别是abc三个文件，里面key=aaa或者key=bbb或者key=ccc， 我们在servlet中通过这三个文件相对路径或者文件名称，去获取绝对路径，然后解析propertest文件，取出里面key的value。

**1.ServletDemo3.java内容**

package com.anthony.servlet;
    
    import java.io.FileInputStream;
    import java.io.FileNotFoundException;
    import java.io.IOException;
    import java.util.Properties;
    
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    
    public class ServletDemo3 extends HttpServlet {
    
    	@Override
    	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    		test1();
    		test2();
    		test3();
    	}
    	
    	// 获取/WEB-INF/a.properties文件路径和key的value
    	private void test1() throws IOException, FileNotFoundException {
    		String path = this.getServletContext().getRealPath("/WEB-INF/a.properties");
    		System.out.println(path);
    		Properties pro = new Properties();
    		pro.load(new FileInputStream(path));
    		System.out.println(pro.getProperty("key"));
    	}
    	
    	// 获取/WEB-INF/a.properties文件路径和key的value
    	private void test2() throws IOException, FileNotFoundException {
    		String path = this.getServletContext().getRealPath("/WEB-INF/classes/b.properties");
    		System.out.println(path);
    		Properties pro = new Properties();
    		pro.load(new FileInputStream(path));
    		System.out.println(pro.getProperty("key"));
    	}
    	
    	// 获取/WEB-INF/a.properties文件路径和key的value
    	private void test3() throws IOException, FileNotFoundException {
    		String path = this.getServletContext().getRealPath("/WEB-INF/classes/com/anthony/servlet/c.properties");
    		System.out.println(path);
    		Properties pro = new Properties();
    		pro.load(new FileInputStream(path));
    		System.out.println(pro.getProperty("key"));
    	}
    	@Override
    	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    		doGet(req, resp);
    	}
    	
    }

**2.web.xml内容**

<?xml version="1.0" encoding="UTF-8"?>
    <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
      
      
      <context-param>
      	<param-name>encoding</param-name>
      	<param-value>GBK</param-value>
      </context-param>
      
      <servlet>
        <servlet-name>servletDemo3</servlet-name>
        <servlet-class>com.anthony.servlet.ServletDemo3</servlet-class>
      </servlet>
      <servlet-mapping>
        <servlet-name>servletDemo3</servlet-name>
        <url-pattern>/demo3</url-pattern>
      </servlet-mapping>
      <welcome-file-list>
        <welcome-file>index.html</welcome-file>
        <welcome-file>index.htm</welcome-file>
        <welcome-file>index.jsp</welcome-file>
        <welcome-file>default.html</welcome-file>
        <welcome-file>default.htm</welcome-file>
        <welcome-file>default.jsp</welcome-file>
      </welcome-file-list>
    </web-app>

**3.部署测试效果**

D:\apache-tomcat-8.5.40\webapps\Servlet01\WEB-INF\a.properties
    aaaaaaaaaaaaa
    D:\apache-tomcat-8.5.40\webapps\Servlet01\WEB-INF\classes\b.properties
    bbbbbbbbbbb
    D:\apache-tomcat-8.5.40\webapps\Servlet01\WEB-INF\classes\com\anthony\servlet\c.properties
    cccccccccccc

看输出结果，正确打印了三个文件的绝对路径，并解析出里面key的value。这里绝对路径是tomcat服务器下路径，并不是Eclipse中项目下路径。