重构代码，结合UI、Controller和Repository：

    1. package com.lugew.springbootddd.snackmachine;
    3. import com.lugew.springbootddd.Entity;
    4. import com.lugew.springbootddd.SnackMachineDto;
    5. import lombok.Getter;
    6. import lombok.Setter;
    8. import java.util.Arrays;
    10. import static com.lugew.springbootddd.snackmachine.Money.None;
    12. @Getter
    13. @Setter
    14. public final class SnackMachine extends Entity {
    15.     private Money moneyInside;
    16.     private Money moneyInTransaction;
    18.     public SnackMachine() {
    19.         moneyInside = None;
    20.         moneyInTransaction = None;
    21.     }
    23.     public void insertMoney(Money money) {
    24.         Money[] coinsAndNotes = {Money.Cent, Money.TenCent, Money.Quarter,
    25.                 Money.Dollar, Money.FiveDollar,
    26.                 Money.TwentyDollar};
    27.         if (!Arrays.asList(coinsAndNotes).contains(money))
    28.             throw new IllegalStateException();
    30.         moneyInTransaction = Money.add(moneyInTransaction, money);
    32.     }
    34.     public void returnMoney() {
    35.         moneyInTransaction = None;
    36.     }
    38.     public void buySnack() {
    39.         moneyInside = Money.add(moneyInside, moneyInTransaction);
    40.         moneyInTransaction = None;
    41.     }
    43.     public SnackMachineDto convertToSnackMachineDto() {
    44.         SnackMachineDto snackMachineDto = new SnackMachineDto();
    45.         snackMachineDto.setId(id);
    46.         snackMachineDto.setMoneyInTransaction(moneyInTransaction.getAmount());
    47.         snackMachineDto.setOneCentCount(moneyInside.getOneCentCount());
    48.         snackMachineDto.setTenCentCount(moneyInside.getTenCentCount());
    49.         snackMachineDto.setQuarterCount(moneyInside.getQuarterCount());
    50.         snackMachineDto.setOneDollarCount(moneyInside.getOneDollarCount());
    51.         snackMachineDto.setFiveDollarCount(moneyInside.getFiveDollarCount());
    52.         snackMachineDto.setTwentyDollarCount(moneyInside.getTwentyDollarCount());
    53.         return snackMachineDto;
    54.     }
    56. }
    1. package com.lugew.springbootddd;
    3. import com.lugew.springbootddd.snackmachine.Money;
    4. import com.lugew.springbootddd.snackmachine.SnackMachine;
    5. import lombok.RequiredArgsConstructor;
    6. import org.springframework.web.bind.annotation.*;
    8. import static com.lugew.springbootddd.snackmachine.Money.*;
    10. /**
    11.  * @author 夏露桂
    12.  * @since 2021/6/10 11:55
    13.  */
    14. @RestController
    15. @RequestMapping("snackmachines")
    16. @RequiredArgsConstructor
    17. public class SnackMachineController {
    18.     private final SnackMachineRepository snackMachineRepository;
    20.     @GetMapping("/{id}")
    21.     @ResponseBody
    22.     public SnackMachineDto getSnackMachine(@PathVariable("id") long id) {
    23.         return snackMachineRepository.findById(id).orElse(null);
    24.     }
    26.     @PutMapping("/{id}/{slotNumber}")
    27.     public void buySnack(@PathVariable("id") long id, @PathVariable("slotNumber")
    28.             int slotNumber) {
    29.         SnackMachineDto snackMachineDto =
    30.                 snackMachineRepository.findById(id).orElse(null);
    31.         SnackMachine snackMachine = snackMachineDto.convertToSnackMachine();
    32.         snackMachine.buySnack();
    33.         snackMachineRepository.save(snackMachine.convertToSnackMachineDto());
    34.     }
    36.     @PutMapping("/{id}/moneyInTransaction/{coinOrNote}")
    37.     public void insertCoinOrNote(@PathVariable("id") long id, @PathVariable("coinOrNote") String coinOrNote) {
    38.         SnackMachineDto snackMachineDto =
    39.                 snackMachineRepository.findById(id).orElse(null);
    40.         SnackMachine snackMachine = snackMachineDto.convertToSnackMachine();
    41.         if (coinOrNote.equalsIgnoreCase("Cent")) snackMachine.insertMoney(Cent);
    42.         else if (coinOrNote.equalsIgnoreCase("TenCent"))
    43.             snackMachine.insertMoney(TenCent);
    44.         else if (coinOrNote.equalsIgnoreCase("Quarter"))
    45.             snackMachine.insertMoney(Quarter);
    46.         else if (coinOrNote.equalsIgnoreCase("Dollar"))
    47.             snackMachine.insertMoney(Dollar);
    48.         else if (coinOrNote.equalsIgnoreCase("FiveDollar"))
    49.             snackMachine.insertMoney(FiveDollar);
    50.         else if (coinOrNote.equalsIgnoreCase("TwentyDollar"))
    51.             snackMachine.insertMoney(TwentyDollar);
    52.         snackMachineRepository.save(snackMachine.convertToSnackMachineDto());
    53.     }
    55.     @PutMapping("/{id}/moneyInTransaction")
    56.     public void returnMoney(@PathVariable("id") long id) {
    57.         SnackMachineDto snackMachineDto =
    58.                 snackMachineRepository.findById(id).orElse(null);
    59.         SnackMachine snackMachine = snackMachineDto.convertToSnackMachine();
    60.         snackMachine.returnMoney();
    61.         snackMachineRepository.save(snackMachine.convertToSnackMachineDto());
    62.     }
    64.     public Money getWholeMoney(SnackMachine snackMachine) {
    65.         return Money.add(snackMachine.getMoneyInside(), snackMachine.getMoneyInTransaction());
    66.     }
    68. }
    1. package com.lugew.springbootddd;
    3. import com.lugew.springbootddd.snackmachine.Money;
    4. import com.lugew.springbootddd.snackmachine.SnackMachine;
    5. import lombok.Getter;
    6. import lombok.Setter;
    8. import javax.persistence.Entity;
    9. import javax.persistence.GeneratedValue;
    10. import javax.persistence.Id;
    12. /**
    13.  * @author 夏露桂
    14.  * @since 2021/6/10 12:00
    15.  */
    16. @Getter
    17. @Setter
    18. @Entity
    19. public class SnackMachineDto {
    20.     @Id
    21.     @GeneratedValue
    22.     private long id;
    23.     private int oneCentCount;
    24.     private int tenCentCount;
    25.     private int quarterCount;
    26.     private int oneDollarCount;
    27.     private int fiveDollarCount;
    28.     private int twentyDollarCount;
    29.     private float moneyInTransaction;
    31.     public SnackMachine convertToSnackMachine() {
    32.         SnackMachine snackMachine = new SnackMachine();
    33.         snackMachine.setId(id);
    34.         snackMachine.setMoneyInTransaction(convertAmountToMoney());
    35.         snackMachine.setMoneyInside(new
    36.                 Money(oneCentCount, tenCentCount, quarterCount, oneDollarCount, fiveDollarCount, twentyDollarCount));
    37.         return snackMachine;
    38.     }
    40.     private Money convertAmountToMoney() {
    41.         float amount = this.moneyInTransaction;
    43.         int twentyDollarCount = (int) (amount / 20f);
    44.         amount %= 20f;
    45.         int fiveDollarCount = (int) (amount / 5f);
    46.         amount %= 5f;
    47.         int oneDollarCount = (int) (amount);
    48.         amount %= 1f;
    49.         int quarterCount = (int) (amount / 0.25f);
    50.         amount %= 0.25f;
    51.         int tenCentCount = (int) (amount / 0.10f);
    52.         amount %= 0.10f;
    53.         int oneCentCount = (int) (amount / 0.01f);
    55.         return new Money(this.moneyInTransaction, oneCentCount, tenCentCount, quarterCount, oneDollarCount, fiveDollarCount, twentyDollarCount);
    56.     }
    57. }
    1. package com.lugew.springbootddd.snackmachine;
    3. import com.lugew.springbootddd.ValueObject;
    4. import lombok.Getter;
    6. /**
    7.  * @author 夏露桂
    8.  * @since 2021/6/7 11:59
    9.  */
    10. @Getter
    11. public class Money extends ValueObject<Money> {
    13.     public static Money None = new Money(0, 0, 0, 0, 0, 0);
    14.     public static Money Cent = new Money(1, 0, 0, 0, 0, 0);
    15.     public static Money TenCent = new Money(0, 1, 0, 0, 0, 0);
    16.     public static Money Quarter = new Money(0, 0, 1, 0, 0, 0);
    17.     public static Money Dollar = new Money(0, 0, 0, 1, 0, 0);
    18.     public static Money FiveDollar = new Money(0, 0, 0, 0, 1, 0);
    19.     public static Money TwentyDollar = new Money(0, 0, 0, 0, 0, 1);
    21.     private final int oneCentCount;
    22.     private final int tenCentCount;
    23.     private final int quarterCount;
    24.     private final int oneDollarCount;
    25.     private final int fiveDollarCount;
    26.     private final int twentyDollarCount;
    27.     private float amount;
    29.     public float getAmount() {
    30.         return oneCentCount * 0.01f + tenCentCount * 0.10f + quarterCount * 0.25f +
    31.                 oneDollarCount * 1f
    32.                 + fiveDollarCount * 5f + twentyDollarCount * 20f;
    33.     }
    35.     public Money(int oneCentCount, int tenCentCount, int quarterCount, int
    36.             oneDollarCount, int fiveDollarCount, int twentyDollarCount) {
    37.         if (oneCentCount < 0)
    38.             throw new IllegalStateException();
    39.         if (tenCentCount < 0)
    40.             throw new IllegalStateException();
    41.         if (quarterCount < 0)
    42.             throw new IllegalStateException();
    43.         if (oneDollarCount < 0)
    44.             throw new IllegalStateException();
    45.         if (fiveDollarCount < 0)
    46.             throw new IllegalStateException();
    47.         if (twentyDollarCount < 0)
    48.             throw new IllegalStateException();
    50.         this.oneCentCount = oneCentCount;
    51.         this.tenCentCount = tenCentCount;
    52.         this.quarterCount = quarterCount;
    53.         this.oneDollarCount = oneDollarCount;
    54.         this.fiveDollarCount = fiveDollarCount;
    55.         this.twentyDollarCount = twentyDollarCount;
    56.     }
    58.     public Money(float amount, int oneCentCount, int tenCentCount, int quarterCount, int
    59.             oneDollarCount, int fiveDollarCount, int twentyDollarCount) {
    60.         this(oneCentCount, tenCentCount, quarterCount, oneDollarCount, fiveDollarCount, twentyDollarCount);
    61.         if (amount < 0) {
    62.             throw new IllegalStateException();
    63.         }
    64.         this.amount = amount;
    65.     }
    67.     public Money substract(Money other) {
    68.         return new Money(
    69.                 oneCentCount - other.oneCentCount,
    70.                 tenCentCount - other.tenCentCount,
    71.                 quarterCount - other.quarterCount,
    72.                 oneDollarCount - other.oneDollarCount,
    73.                 fiveDollarCount - other.fiveDollarCount,
    74.                 twentyDollarCount - other.twentyDollarCount);
    75.     }
    77.     public static Money add(Money money1, Money money2) {
    79.         return new Money(
    80.                 money1.oneCentCount + money2.oneCentCount,
    81.                 money1.tenCentCount + money2.tenCentCount,
    82.                 money1.quarterCount + money2.quarterCount,
    83.                 money1.oneDollarCount + money2.oneDollarCount,
    84.                 money1.fiveDollarCount + money2.fiveDollarCount,
    85.                 money1.twentyDollarCount + money2.twentyDollarCount);
    86.     }
    88.     @Override
    89.     protected boolean equalsCore(Money other) {
    90.         return oneCentCount == other.oneCentCount
    91.                 && tenCentCount == other.tenCentCount
    92.                 && quarterCount == other.quarterCount
    93.                 && oneDollarCount == other.oneDollarCount
    94.                 && fiveDollarCount == other.fiveDollarCount
    95.                 && twentyDollarCount == other.twentyDollarCount;
    96.     }
    98.     @Override
    99.     protected int getHashCodeCore() {
    100.         int hashCode = oneCentCount;
    101.         hashCode = (hashCode * 397) ^ tenCentCount;
    102.         hashCode = (hashCode * 397) ^ quarterCount;
    103.         hashCode = (hashCode * 397) ^ oneDollarCount;
    104.         hashCode = (hashCode * 397) ^ fiveDollarCount;
    105.         hashCode = (hashCode * 397) ^ twentyDollarCount;
    106.         return hashCode;
    107.     }
    109.     @Override
    110.     public String toString() {
    111.         if (getAmount() < 1)
    112.             return "¢" + getAmount() * 100;
    113.         return "$" + getAmount();
    114.     }
    115. }
    1. package com.lugew.springbootddd;
    3. import org.springframework.data.repository.CrudRepository;
    5. /**
    6.  * @author 夏露桂
    7.  * @since 2021/6/15 10:50
    8.  */
    9. public interface SnackMachineRepository extends CrudRepository<SnackMachineDto, Long> {
    10. }
    1. const rootURI = "http://localhost:23333/snackmachines/1";
    2. getSnackMachine();
    4. function getSnackMachine() {
    5.     $.get(rootURI, function (data, status) {
    6.         console.log(data)
    7.         $('#moneyInserted').html(data.moneyInTransaction);
    8.         $('#cent').html(data.moneyInside.oneCentCount);
    9.         $('#tenCent').html(data.moneyInside.tenCentCount);
    10.         $('#quarter').html(data.moneyInside.quarterCount);
    11.         $('#dollar').html(data.moneyInside.oneDollarCount);
    12.         $('#fiveDollar').html(data.moneyInside.fiveDollarCount);
    13.         $('#twentyDollar').html(data.moneyInside.twentyDollarCount);
    14.     });
    15. }
    17. $("button").click(function () {
    18.     switch (this.id) {
    19.         case "btnInsertCent" :
    20.             insert("Cent")
    21.             break;
    22.         case "btnInsertTenCent" :
    23.             insert("TenCent")
    24.             break;
    25.         case "btnInsertQuarter" :
    26.             insert("Quarter")
    27.             break;
    28.         case "btnInsertDollar" :
    29.             insert("Dollar")
    30.             break;
    31.         case "btnInsertFiveDollar" :
    32.             insert("FiveDollar")
    33.             break;
    34.         case "btnInsertTwentyDollar" :
    35.             insert("TwentyDollar")
    36.             break;
    37.         case "btnReturnMoney" :
    38.             returnMoney()
    39.             break;
    40.         case "btnBuy" :
    41.             buy("1")
    42.             break;
    43.         default :
    44.             break;
    45.     }
    46. });
    48. function insert(coinOrNote) {
    49.     $.ajax({
    50.         url: rootURI + '/moneyInTransaction/' + coinOrNote,
    51.         type: 'PUT',
    52.         success: function (result) {
    53. // Do something with the result
    54.         }
    55.     });
    56.     location.reload();
    57. }
    59. function returnMoney() {
    60.     $.ajax({
    61.         url: rootURI + '/moneyInTransaction',
    62.         type: 'PUT',
    63.         success: function (result) {
    64. // Do something with the result
    65.         }
    66.     });
    67.     location.reload();
    68. }
    70. function buy(position) {
    71.     $.ajax({
    72.         url: rootURI + '/' + position,
    73.         type: 'PUT',
    74.         success: function (result) {
    75.         }
    76.     });
    77.     location.reload();
    78. }

    再次运行程序就能看到投币、退币和购买功能正常使用：

    上述代码有几处缺陷，比如amount转换精度会出现问题，简单起见，这里不做修复，感兴趣的读者可自行重构。