java - 如何在 JSF 项目中获取文件资源

Question

我正在尝试编写一个简单的 JSF 应用程序来让用户在 Web 浏览器上登录，然后我的应用程序应该在 MySQL 数据库上验证用户凭据。

我无法让我的代码查看 database.properties 文件。我将以下代码用于我所有的独立数据库程序，但我必须对我正在编写的这个 JSF 应用程序进行一些修改。

下一行大约有 3/4 会抛出 ClassNotFoundException，因为我的 url 变量为空，我不知道为什么: FileInputStream in = new FileInputStream(url.getFile());//如果在服务器上则执行此操作

谁能帮帮我？谢谢!有问题的代码在方法 init(String fileName) 的前半部分。

下面是获取数据源的整个类:

package com.gmail.gmjord.datasource;

import java.net.URL;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.Properties;

/**
 * A simple data source for getting database connections.
 */
public class SimpleDataSource {
    private static String urlString;
    private static String username;
    private static String password;

    /**
     * Initializes the data source.
     * 
     * @param fileName
     *            the name of the property file that contains the database
     *            driver, URL, username, and password
     */
    public static void init(String fileName) throws IOException,
            ClassNotFoundException {
        // ****************** Added code for getting resource on a server
        // *********************
        System.out.println("In SimpleDataSource.init()");
        **Class cls = Class.forName("com.gmail.gmjord.datasource.SimpleDataSource");**

        System.out.println("Made it here 1");
        // returns the ClassLoader object associated with this Class
        ClassLoader cLoader = cls.getClassLoader();
        System.out.println("Made it here 2");

        System.out.println(cLoader.getClass());

        // finds resource with the given name
        URL url = cLoader.getResource(fileName); // This is the original line I copied from the web page
        //URL url = cls.getClass().getClassLoader().getResource(fileName); // This is TA's way
        System.out.println("Made it here 3");
        System.out.println("File: " + fileName);
        System.out.println("url Value = " + url);

        // ********* End of code for getting resource on a      server*******************************************************

        Properties props = new Properties();
        //System.out.println("File: " + fileName);
        //FileInputStream in = new FileInputStream(fileName); // Do this if not on server
        FileInputStream in = new FileInputStream(url.getFile()); // Do this if on Server
        props.load(in);

        String driver = props.getProperty("jdbc.driver");
        urlString = props.getProperty("jdbc.url");
        username = props.getProperty("jdbc.username");
        if (username == null)
            username = "";
        password = props.getProperty("jdbc.password");
        if (password == null)
            password = "";
        if (driver != null)
            Class.forName(driver);
    }

    /**
     * Gets a connection to the database.
     * 
     * @return the database connection
     */
    public static Connection getConnection() throws SQLException {
        return DriverManager.getConnection(urlString, username, password);
    }
}

Answer 1

首先需要将里面的文件移动到src文件夹下，接下来的代码必须在src文件夹的根目录下，可以这样加载文件:

Properties properties = new Properties();   
properties.load(SimpleDataSource.class.getResourceAsStream("/database.properties"));