如何使用自定義構造函數參數創建Autowire

Question

如何使用自定義構造函數參數在Spring中創建Autowire？以下是我的示例代碼。我越來越無法autowire字段;沒有默認構造函數找到errors.I不能引入默認構造函數，因爲AbstractExecutor類沒有默認構造函數。

IExecutor

public interface IExecutor { 
    Object execute(); 
} 

AbstractExecutor

public abstract class AbstractExecutor implements IExecutor { 
    private IInputPropertyBean inputObject; 
    private IOutputPropertyBean outputObject; 
    public AbstractExecutor(IInputPropertyBean inputObject, IOutputPropertyBean outputObject) { 
     this.inputObject = inputObject; 
     this.outputObject = outputObject; 
    } 
    public abstract boolean isValidInput(IInputPropertyBean inputObject) ; 
    public abstract IInputPropertyBean getInputValues(IInputPropertyBean inputObject); 
    public abstract IOutputPropertyBean process(IInputPropertyBean attribute); 
    public abstract IOutputPropertyBean getOutputValues(IInputPropertyBean inputObject, IOutputPropertyBean outputObject; 
    @Override 
    public Object execute(){ 
     if(isValidInput(inputObject)){ 
      IInputPropertyBean inputAttribute = getInputValues(inputObject); 
      IOutputPropertyBean outputAttribute = process(inputAttribute); 
      outputObject = (IOutputPropertyBean) getOutputValues(outputAttribute, outputObject); 
      return outputObject; 
     } 
    } 
} 

UserExecutor

@Repository("userExecutor") 
public class UserExecutor extends AbstractExecutor { 
    public UserExecutor(@Qualifier("userInput") IInputPropertyBean inputObject, @Qualifier("userOutput")IOutputPropertyBean outputObject) { 
     super(inputObject, outputObject); 
    } 

//override methods 
} 

IInputPropertyBean

public interface IInputPropertyBean { } 

IOutputPropertyBean

public interface IOutputPropertyBean { } 

UserInput

@Component("userInput") 
public class UserInput implements IInputPropertyBean { //user sepecific properties } 

UserOutput

@Component("userOutput") 
public class UserOutput implements IOutputPropertyBean { //user sepecific properties } 

UserServiceImpl

@Service 
public class UserServiceImpl implements IUserService { 

    @Autowired 
    @Qualifier("userExecutor") 
    private UserExecutor userExecutor; 


    @Override 
    public UserOutput userOperation(UserInput userInput, UserOutput userOutput) { 
     // How to @Autowire UserExecutor with userInput, userOutput comming in service parameter. 

       //IExecutor executor = new UserExecutor(userInput, userOutput); 
    //return (UserOutput) executor.execute(); 
    } 
} 

Answer 1

你失蹤@Autowired構造函數爲UserExecutor。以下將工作：

@Repository("userExecutor") 
public class UserExecutor extends AbstractExecutor { 
    @Autowired 
    public UserExecutor(@Qualifier("userInput") UserInput input 
    , @Qualifier("userOutput") UserOutput output) { super(input, output); } 
} 

工作代碼可在Github。

---

您還將受益於使用仿製藥。

public interface IInput {} 
public interface IOutput {} 

public interface IExecutor<I extends IInput, O extends IOutput> { 
    O execute(I i); 
} 

public class AbstractExecutor<I extends IInput, O extends IOutput> 
     implements IExecutor<I, O> { 
    private final I input; 
    private final O output; 

    protected AbstractExecutor(I input, O output) { 
    this.input = input; 
    this.output = output; 
    } 

    public O execute(I i) { 
    ... 
    } 
} 

@Component 
public class UserInput implements IInput {} 
@Component 
public class UserOutput implements IOutput {} 
@Repository 
public class UserExecutor extends AbstractExecutor<UserInput, UserOutput> { 
    @Autowired 
    public UserExecutor(UserInput input, UserOutput output) { 
    super(input, output); 
    } 
} 

public interface IUserService { 
    UserOutput execute(UserInput input, UserOutput output); 
} 

@Service 
public UserService implements IUserService { 
    private final UserExecutor executor; 

    @Autowired 
    public UserService(UserExecutor executor) { 
    this.executor = executor; 
    } 

    public UserOutput execute(UserInput input) { 
    return executor.execute(input); 
    } 
} 

你會避免使用@Qualifier，Object和類型鑄造無處不在。