考虑在你的配置中定义一个 'com.example.demo.Commands$DefaultIO' 类型的 bean

Question

I'm trying to run this code using Spring boot:

public interface DefaultIO{
    public String readText();

    public void write( String text);
    public float readVal();
    public void write( float val);
    public default void uploadFile(String exit, String outputPath) {
        try {
            PrintWriter writer = new PrintWriter(new FileWriter(outputPath));
            String line;
            while (  (line = readText()) != null) {
                if(line.equals(exit))
                    break;
                if(line.equals(""))
                    continue;
                writer.println(line);
            }
            writer.close();
        } catch (FileNotFoundException e) {
            System.out.println("An error occurred.");
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    public default String[] downloadFile(String outputFileName) {
        try {
            Scanner scanner=new Scanner(new BufferedReader(new FileReader(outputFileName)));
            String str="";
            while (scanner.hasNext()){
                str+=scanner.nextLine()+"split";
            }
            scanner.close();
            return str.split("split");
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        return "doesnt work".split(" ");
    }


    void close();

}

DefaultIO dio;
public Commands(DefaultIO dio) {
    this.dio=dio;
}

public abstract class Command{
    protected String description;

    public Command(String description) {
        this.description=description;
    }

    public abstract void execute();
}

public  class mainCommand extends Command{


    public mainCommand() {
        super("Welcome to the Anomaly Detection Server.\n" +
                "Please choose an option:\n");
    }


    @Override
    public void execute() {
        CLI cli= new CLI(dio);
        cli.commands.forEach(command -> dio.write( command.description));
        int clientNumber = (int) dio.readVal();
        cli.commands.get(clientNumber).execute();
    }
}

and run this code from CLI class:

ArrayList<Command> commands;
DefaultIO dio;
Commands c;

public CLI(DefaultIO dio) {
    this.dio=dio;
    c=new Commands(dio); 
    commands=new ArrayList<>();
    commands.add(c.new mainCommand());
    commands.add(c.new uploadCommand());
    commands.add(c.new algorithmCommand());
    commands.add(c.new detectCommand());
    commands.add(c.new displayCommand());
    commands.add(c.new analyzeCommand());
    commands.add(c.new exitCommand());

    // implement
}



@GetMapping("/test")
public void start() {
    // implement
    commands.get(0).execute();
}

}

this is my main:

    SpringApplication.run(DemoApplication.class, args);
}
private Scanner s;
@Override
public void run(String... args) throws Exception {
     s = new Scanner(System.in);
    PrintWriter pw = new PrintWriter(System.out);
    StandrtIO sio=new StandrtIO(s);
    CLI cli=new CLI(sio);
    cli.start();
    s.close();
    sio.close();
}

and i get this error:

Parameter 0 of constructor in com.example.demo.CLI required a bean of type 'com.example.demo.Commands$DefaultIO' that could not be found.

Action:

Consider defining a bean of type 'com.example.demo.Commands$DefaultIO' in your configuration.

Answer 1

Spring is trying to inject a DeafultIO bean into the CLI constructor.

You need to implements the DeafultIO interface with a class and annotate that class with @Component which will tell Spring it's a bean and needs to be initialized at start up.