Web读取配置文件得到数据库连接

虽然用Java测试过，通过读取配置文件来得到数据库的连接字符串成功了，但是使用Web的时候，还是碰到了路径问题，经过调试，终于找到了规律。
database.properties

Java 代码

1. jdbc.drivers=oracle.jdbc.driver.OracleDriver  
2. jdbc.url=jdbc:oracle:thin:@localhost : 1521 :ORCL  
3. jdbc.username=scott  
4. jdbc.password=tiger  

jdbc.drivers=oracle.jdbc.driver.OracleDriver
jdbc.url=jdbc:oracle:thin:@localhost:1521:ORCL
jdbc.username=scott
jdbc.password=tiger

DatabaseUtil

Java 代码

1. package  com.util;  
2.   
3. import  java.io.IOException;  
4. import  java.io.InputStream;  
5. import  java.sql.Connection;  
6. import  java.sql.DriverManager;  
7. import  java.sql.SQLException;  
8. import  java.util.Properties;  
9.   
10. import  oracle.sql.CLOB;  
11.   
12. public   class  DatabaseUtil {  
13.     private   static  DatabaseUtil dbUtil;  
14.     private  String drivers;  
15.     private  String url;  
16.     private  String username;  
17.     private  String password;  
18.     //加反斜线就表示在默认包目录，不加则表示在与当前类同路径去查找该属性文件   
19.     private   static  String FILE_PATH_NAME =  "/database.properties" ;  
20.     private   void  init() {  
21.         try  {  
22.             InputStream in = getClass().getResourceAsStream(FILE_PATH_NAME);  
23.             Properties props = new  Properties();  
24.           
25.             props.load(in);  
26.             in.close();  
27.             drivers = props.getProperty("jdbc.drivers" );  
28.             url = props.getProperty("jdbc.url" );  
29.             username = props.getProperty("jdbc.username" );  
30.             password = props.getProperty("jdbc.password" );  
31.         } catch  (IOException e) {  
32.             e.printStackTrace();  
33.         }  
34.           
35.     }  
36.       
37.     private  DatabaseUtil() {  
38.         init();  
39.     }  
40.     public   static  DatabaseUtil getInstance() {  
41.         if (dbUtil ==  null ) {  
42.             dbUtil = new  DatabaseUtil();  
43.         }  
44.         return  dbUtil;   
45.     }  
46.     public  Connection getConnection() {  
47.           
48.         Connection conn = null ;  
49.         try  {  
50.             Class.forName(drivers);  
51.             conn = DriverManager.getConnection(url, username, password);  
52.         } catch  (SQLException e) {  
53.             e.printStackTrace();  
54.         } catch  (ClassNotFoundException e) {  
55.             e.printStackTrace();  
56.         }  
57.         return  conn;  
58.     }  
59. }  

package com.util;

import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Properties;

import oracle.sql.CLOB;

public class DatabaseUtil {
	private static DatabaseUtil dbUtil;
	private String drivers;
	private String url;
	private String username;
	private String password;
	//加反斜线就表示在默认包目录，不加则表示在与当前类同路径去查找该属性文件
	private static String FILE_PATH_NAME = "/database.properties";
	private void init() {
		try {
			InputStream in = getClass().getResourceAsStream(FILE_PATH_NAME);
			Properties props = new Properties();
		
			props.load(in);
			in.close();
			drivers = props.getProperty("jdbc.drivers");
			url = props.getProperty("jdbc.url");
			username = props.getProperty("jdbc.username");
			password = props.getProperty("jdbc.password");
		} catch (IOException e) {
			e.printStackTrace();
		}
		
	}
	
	private DatabaseUtil() {
		init();
	}
	public static DatabaseUtil getInstance() {
		if(dbUtil == null) {
			dbUtil = new DatabaseUtil();
		}
		return dbUtil; 
	}
	public Connection getConnection() {
		
		Connection conn = null;
		try {
			Class.forName(drivers);
			conn = DriverManager.getConnection(url, username, password);
		} catch (SQLException e) {
			e.printStackTrace();
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}
		return conn;
	}
}

路径问题已经做了注释，在这里就不多讲了。
现在写一个测试页面。
connTest.jsp

Java 代码

1. <%@ page language= "java"   import = "java.util.*"  pageEncoding= "UTF-8" %>  
2. <jsp:directive.page import = "com.util.DatabaseUtil" />  
3. <jsp:directive.page import = "java.sql.Connection" />  
4. <%  
5. String path = request.getContextPath();  
6. String basePath = request.getScheme()+"://" +request.getServerName()+ ":" +request.getServerPort()+path+ "/" ;  
7. %>  
8.   
9. <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" >  
10. <html>  
11.   <head>  
12.     <base href="<%=basePath%>" >  
13.       
14.     <title>My JSP 'connTest.jsp'  starting page</title>  
15.       
16.     <meta http-equiv="pragma"  content= "no-cache" >  
17.     <meta http-equiv="cache-control"  content= "no-cache" >  
18.     <meta http-equiv="expires"  content= "0" >      
19.     <meta http-equiv="keywords"  content= "keyword1,keyword2,keyword3" >  
20.     <meta http-equiv="description"  content= "This is my page" >  
21.     <!--  
22.     <link rel="stylesheet"  type= "text/css"  href= "styles.css" >  
23.     -->  
24.   
25.   </head>  
26.     
27.   <body>  
28.     <%   
29.         DatabaseUtil dbUtil = DatabaseUtil.getInstance();  
30.         Connection conn = dbUtil.getConnection();  
31.         out.println(conn);  
32.         out.println("获取连接成功！" );  
33.     %>  
34.   </body>  
35. </html>