How to create try{ }catch(){ } block with custom message?-CodePudding

I have method looks like:

public Optional<UserDTO> getUser(String id) {
    if (userRepository.findById(Integer.valueOf(id)).isPresent()) {
        return userRepository.findById(Integer.parseInt(id))
                .map(this::map);
    }
    throw new UserNotFoundException("User wasn't found");
}

But I want to make it with try{} catch(){} blocks, I've tried to make it like this:


public Optional<UserDTO> getUser(String id) {
    try {
        userRepository.findById(Integer.valueOf(id)).isPresent();
        return userRepository.findById(Integer.parseInt(id))
                .map(this::map);
    } catch (UserNotFoundException userNotFoundException){
        var message = "User wasn't found";
        System.out.println(message);
    }
}

but it had't thrown an exception in the case of wrong id and shown a mistake with an absence of return block.

Could you help me to find the possible solution?

CodePudding user response：

It will not throw an exception because there are none to throw in your code, you can do what you want with one line like so

userRepository.findById(Integer.valueOf(id)).orElseThrow(() -> new UserNotFoundException("User wasn't found"));

CodePudding user response：

You forgot the if part.

public Optional<UserDTO> getUser(String id) {
try {
    if(userRepository.findById(Integer.valueOf(id)).isPresent()){
      return userRepository.findById(Integer.parseInt(id))
            .map(this::map);
    } else {
      throw new UserNotFoundException();
    }
} catch (UserNotFoundException userNotFoundException){
    var message = "User wasn't found";
    System.out.println(message);
}

}