I having problems defining database properties in different environments. The properties file looks like this:

```
db.url-DEV=host1:port:con...
db.user-DEV=user1

db.url-PROD=host2:port:con...
db.user-PROD=user2

```

The suffixes (-DEV,-PROD) are set on server side using a system property. How may I configure my PropertyPlaceholderConfigurer to check for a system property to switch to the right configuration? There has to be a default value if a system property is not set.

I have tried something like this, but that did not work:

```
${#{'db.url'+${systemEnvironmentVar}}}

```

The PropertyConfigurer says 'property with name 'db.url'+${systemEnvironmentVar} not found.