Java从Web目录读取属性文件

Question

I'm trying to read a config.properties file from my JARs local directory where it's run from a website. I have tried a bunch of different code from Streaming it to getting the class path, etc. Finally the one I'm trying now is the following code:

        FileInputStream f = new FileInputStream("./config.properties");
        if(f != null) {
            prop.load(f);
            db = prop.getProperty("database");
            dbuser = prop.getProperty("dbuser");
            dbpass = prop.getProperty("dbpass");
            host = prop.getProperty("host");
            iloc = prop.getProperty("iloc");
        }

This evaluates perfectly while testing and running from inside Netbeans, but the second I place it on the web and run it, it no longer finds the config file even though it's the same file in the same directory. I've tried with the ./ and without, still same result.

Answer 1

you have to have some absolutes or some run time params. What we do is have an app home as a system property. thus when starting java on windows its /app1 but on a server its /etc/app1

Using the -D when launching java or javaw

java -Dapp.home=/etc/app1 -Dapp.other=somevalue my.package.AppMain

Then in our app we have a FileUtils class that reads this in static init and has a static getter for it.

Sample

public class FileUtils{
    private static File appHome = null;
    static{
        String home = System.getProperty("app.home");//-D that you specify or some standard that java has see javadoc
        if(home == null){
            //logger as needed
            home = "/app1";

        }
        appHome = new File(home);
    }


    public static File getAppHome(){
        return appHome;
        }


    ...

a website - running java as the web server/ app server has a file system too. if you do not have access to it then you cant edit the config also right? if you know the path to the config but cannot change the java command you could do something like this:

Suggestion 1 on your dev system make an arbitary file like /dev/randome4343433Name.txt if this file exists you know yur in dev and use that path else go for the path in the server.

Suggestion 2 Or use the path on the server. Even if the server is linux and dev is windows you can do this just use this slash / and make the same file system in the dev drive but do not mention the drive letter in code. so if on server its at /etc/app1/config.txt then on local in drive you start make a etc\\app1 folder and put config there and uin code use "/etc/app1/config.txt"

Answer 2

For java.applet.Applet or JApplet use Gets the URL of the document in which this applet is embedded. then make a new URL adding the path to config.txt, open the input stream on URL and you can read the file on the client.

remember everything you do is on client, so you cannot write back unless you have a jsp page on server and connect to that using some security (password) from the applet

Answer 3

In commons-configurations jar there is this class:

PropertiesConfiguration cfg = new PropertiesConfiguration("filePath");

Just check it