如何使用带有属性文件的Eclipse“导出为jar选项”来构建jar

Question

public xFbConfigReader()
{

    //props = new Properties();
    propsdatabase = new Properties();

    try 
    {
        // load a properties file
        InputStream dbin = getClass().getResourceAsStream("/properties/database.properties");


        propsdatabase.load(dbin);

    } 
    catch (IOException ex) 
    {
        ex.printStackTrace();
    }

}

I keep My properties File named 'Database.properties' in a folder where the project is named 'Properties'.

When I do a Export as jar in Eclipse . The Properties Folder is visible.

But When I run the program it shows that there is a NUll point exception in dbin.

So which means I require the proper way to form a jar in Eclipse .Kindly suggest.

Answer 1

The better solution while handling properties file would be reading

static Properties databaseproperties= new Properties();
    static {
        try {
            connectionProps.load(YourClassName.class.getClassLoader()
                    .getResourceAsStream("databaseproperties.properties"));
        } catch (Exception e) {
            System.out.println("Exception is " + e.getMessage());
        }
    }

This is better approch because

• we can move our properties file to someother folder.
• And infact we can keep properties folder out side of jar. say you can create a folder called Configuration where you can include all the properties files. As it is out side of jar you can change the properties file when ever is required.
• For change in properties file no need to unjar it.

(OR) simply you can make this change no need to think about directory structure

1. Step 1: Move properties file to SRC

2. step 2: change this line as follows

   InputStream dbin = getClass().getResourceAsStream("/database.properties");

This is not much different from previous code as it is anyway stays inside the JAR file.

Answer 2

you are getting null pointer exception because properties file is not loaded try to use FileInputStream to load the properties as follows FileInputStream dbin = new FileInputStream("/properties/database.properties"); properties.load(dbin);