Spring-将Web表单绑定到application.properties文件

Question

I have a web form that enables one to update the appliaction.properties, so that user does not have to go to the file and edit it. I wants to load the value from the application.properties file and display in the web form textfield. After the user edit the some changes, user can update the application.properties file.

Question - How can I bind my web form to application.properties file other than using @value in Spring? As the key/value pairs might be updated through web form, I believe @value is not the right choice.

Answer 1

The application properties are for the settings the application needs to load when it starts up, and then connects to a database for example, with the username and password specified in that file (although environment variables can also be used.)

You shouldn't really edit this file at run-time, with the exception of using the Refresh Scope annotation. But I don't advise you do that as it's fairly hard in practice to achieve an application which supports changing configuration at run-time.

There is also Spring Cloud Config server for reloading properties at run-time and that provides a REST API although you mainly just use git with that one.

But the key is here that they are all mentioning configuration which is only something developers do. I also don't think you want to use the filesystem for storing your state, much rather have database. There are many reasons to use a file system over a database I won't go into them now.

I will make the assumption you are a beginner looking at your rep. Best advice I can give you is to watch what everyone else is doing and learn from that first. Most of the time people are all doing similar things because it is the right thing to do. If you can't find anybody else changing properties files based on form submissions in their spring app but rather using databases you probably want to go with the database.

Answer 2

We were in a similar situation last month where client need update in configuration file in run time. We created a central Spring component that loads all properties from file using @Value

@Component
public class ConfigurationManagerComponent{
  @Value("conf.username")
  private String userName;
  @Value("conf.email");
  private String email;
  /*
   * All your attributes
  */
  //getters and setters
  public String getUserName(){
    return this.userName;
  }
  public void setUserName(String userName){
   // first set the value to this class (component)
   this.userName=userName;
   //second save this value in the properties file
   //a specific method you have to implement
    saveproperties("conf.username",userName); 
  }
  /*
   * Do like this for all your getters and setters
  */ 
}

Then, in any time you need to get or save properties, just inject this component and use its getters and setters

@Autowired
ConfigurationManagerComponent configComponent;
String myActualUserName=configComponent.getUserName();

So then you can get all your data in your controller from config component and set them to your spring model to fill form in webpage, and when saving after edit, you can always use setters of your config component(update class and properties file).

This method is not a standard, just a solution we employed to resolve a problem, it's giving good results right now. You can also check Apache commons configuration Here for other solutions.. Hope this will help.