java项目读取properties路径问题

java项目读取properties路径问题

1.项目结构

2.方法一

/*** 传统方式*/private void test1() throws FileNotFoundException, IOException {// FileInputStream in = new FileInputStream("src/main/resources/properties/url.properties"); // 错误写法1  java项目中这么写是正确的，web项目不行 //  FileInputStream in = new FileInputStream("classes/test.properties");//错误写法2     FileInputStream in = new FileInputStream("test.properties");//把test.properties文件copy到tomcate的bin目录下     Properties prop = new Properties();     prop.load(in);     String driver = prop.getProperty("driver");     String url = prop.getProperty("url");     System.out.println("driver-==-="+driver);     System.out.println("url-==-="+url);}

解析：
错误写法1：要是java项目，这么写是正确的，可以读到配置文件，但是web项目就会报找不到路径的错误，因为web项目会把test.properties文件编译到WEB-INF目录下的classes文件夹下。
错误写法2：这么看似没问题了，但是会报跟1一样的错误，因为这是相对路径，谁调用此类就是相对于谁，故这是相对于java虚拟机，本项目时用tomcate启动的java虚拟机，故回去tomcate的bin目录下去找classes/test.properties文件，找不到故报错

3.方法二

private void test2() throws IOException {System.out.println("test2");InputStream in = this.getServletContext().getResourceAsStream("WEB-INF/classes/test.properties"); Properties prop = new Properties(); prop.load(in); String driver = prop.getProperty("driver"); String url = prop.getProperty("url"); System.out.println("driver-==-="+driver); System.out.println("url-==-="+url);}

4.方法三

private void test3() throws FileNotFoundException, IOException {String path = this.getServletContext().getRealPath("WEB-INF/classes/test.properties");//拿到资源在硬盘上的路径FileInputStream in = new FileInputStream(path); System.out.println("test3"); Properties prop = new Properties(); prop.load(in); String driver = prop.getProperty("driver"); String url = prop.getProperty("url"); System.out.println("driver-==-="+driver); System.out.println("url-==-="+url);}

5.方法四

private void test4() throws IOException {/** * 读取webroot目录下的配置文件 */ System.out.println("test4"); InputStream in = this.getServletContext().getResourceAsStream("/WEB-INF/test11.properties"); Properties prop = new Properties(); prop.load(in); String driver = prop.getProperty("driver"); String url = prop.getProperty("url"); System.out.println("driver-==-="+driver); System.out.println("url-==-="+url);}

6.方法五

private void test5() throws IOException {/** * 类装载器方式读取，我常用的方式 */InputStream in  = readProp.class.getClassLoader().getResourceAsStream("test.properties");System.out.println("类装载器方式"); Properties prop = new Properties(); prop.load(in); String driver = prop.getProperty("driver"); String url = prop.getProperty("url"); System.out.println("driver-==-="+driver); System.out.println("url-==-="+url);}