领域驱动设计Demo

bank-application/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <parent>
+        <artifactId>dddbook</artifactId>
+        <groupId>com.example</groupId>
+        <version>1.0-SNAPSHOT</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>bank-application</artifactId>
+
+
+    <dependencies>
+        <dependency>
+            <groupId>com.example</groupId>
+            <artifactId>bank-domain</artifactId>
+            <version>${dddbook.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>com.example</groupId>
+            <artifactId>bank-persistence</artifactId>
+            <version>${dddbook.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-jdbc</artifactId>
+        </dependency>
+    </dependencies>
+</project>

bank-application/src/main/java/com/example/bank/application/TransferService.java

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+package com.example.bank.application;
+
+import com.example.bank.common.Result;
+import com.example.bank.exception.DailyLimitExceededException;
+import com.example.bank.exception.InsufficientFundsException;
+import com.example.bank.exception.InvalidCurrencyException;
+
+import java.math.BigDecimal;
+
+public interface TransferService {
+
+    Result<Boolean> transfer(Long sourceUserId, String targetAccountNumber, BigDecimal targetAmount, String targetCurrency) throws Exception, DailyLimitExceededException;
+
+}

bank-application/src/main/java/com/example/bank/application/impl/TransferServiceImpl.java

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+package com.example.bank.application.impl;
+
+import com.example.bank.application.TransferService;
+import com.example.bank.common.Result;
+import com.example.bank.domain.entity.Account;
+import com.example.bank.domain.service.AccountTransferService;
+import com.example.bank.domain.types.AuditMessage;
+import com.example.bank.exception.DailyLimitExceededException;
+import com.example.bank.exception.InsufficientFundsException;
+import com.example.bank.exception.InvalidCurrencyException;
+import com.example.bank.external.ExchangeRateService;
+import com.example.bank.messaging.AuditMessageProducer;
+import com.example.bank.repository.AccountRepository;
+import com.example.bank.types.*;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+import java.math.BigDecimal;
+
+@Service
+public class TransferServiceImpl implements TransferService {
+
+    @Autowired
+    private AccountRepository accountRepository;
+
+    private AuditMessageProducer auditMessageProducer;
+    private ExchangeRateService exchangeRateService;
+    private AccountTransferService accountTransferService;
+
+//    @Transactional(rollbackFor = Exception.class)
+    @Override
+    public Result<Boolean> transfer(Long sourceUserId, String targetAccountNumber, BigDecimal targetAmount, String targetCurrency) throws Exception, DailyLimitExceededException {
+        Money targetMoney = new Money(targetAmount, new Currency(targetCurrency));
+
+        Account sourceAccount = accountRepository.find(new UserId(sourceUserId));
+
+        Account targetAccount = accountRepository.find(new AccountNumber(targetAccountNumber));
+
+        ExchangeRate exchangeRate = exchangeRateService.getExchangeRate(sourceAccount.getCurrency(), targetMoney.getCurrency());
+
+        accountTransferService.transfer(sourceAccount, targetAccount, targetMoney, exchangeRate);
+
+        accountRepository.save(sourceAccount);
+
+        accountRepository.save(targetAccount);
+
+        // 发送审计消息
+        AuditMessage message = new AuditMessage(sourceAccount, targetAccount, targetMoney);
+        auditMessageProducer.send(message);
+
+        return Result.success(true);
+    }
+}

bank-domain/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <parent>
+        <artifactId>dddbook</artifactId>
+        <groupId>com.example</groupId>
+        <version>1.0-SNAPSHOT</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>bank-domain</artifactId>
+
+
+    <dependencies>
+        <dependency>
+            <groupId>com.example</groupId>
+            <artifactId>bank-types</artifactId>
+            <version>${dddbook.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot</artifactId>
+        </dependency>
+    </dependencies>
+
+</project>

bank-domain/src/main/java/com/example/bank/domain/entity/Account.java

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+package com.example.bank.domain.entity;
+
+import com.example.bank.exception.DailyLimitExceededException;
+import com.example.bank.exception.InsufficientFundsException;
+import com.example.bank.exception.InvalidCurrencyException;
+import com.example.bank.exception.MoneyAmoutNotNullException;
+import com.example.bank.types.*;
+
+public class Account {
+
+    private AccountId id;
+    private AccountNumber accountNumber;
+    private UserId userId;
+    private Money available;
+    private Money dailyLimit;
+
+    private Currency currency;
+
+    public AccountId getId() {
+        return id;
+    }
+
+    public void setId(AccountId id) {
+        this.id = id;
+    }
+
+    public AccountNumber getAccountNumber() {
+        return accountNumber;
+    }
+
+    public void setAccountNumber(AccountNumber accountNumber) {
+        this.accountNumber = accountNumber;
+    }
+
+    public UserId getUserId() {
+        return userId;
+    }
+
+    public void setUserId(UserId userId) {
+        this.userId = userId;
+    }
+
+    public Money getAvailable() {
+        return available;
+    }
+
+    public void setAvailable(Money available) {
+        this.available = available;
+    }
+
+    public Money getDailyLimit() {
+        return dailyLimit;
+    }
+
+    public void setDailyLimit(Money dailyLimit) {
+        this.dailyLimit = dailyLimit;
+    }
+
+    public Currency getCurrency() {
+        return currency;
+    }
+
+    public void setCurrency(Currency currency) {
+        this.currency = currency;
+    }
+
+    // 转出
+    public void withdraw(Money money) throws Exception, DailyLimitExceededException {
+        if (this.available.compareTo(money) < 0){
+            throw new InsufficientFundsException();
+        }
+
+        if (this.dailyLimit.compareTo(money) < 0){
+            throw new DailyLimitExceededException();
+        }
+
+        this.available = this.available.subtract(money);
+    }
+
+    // 转入
+    public void deposit(Money money) throws InvalidCurrencyException, MoneyAmoutNotNullException {
+       if (!this.getCurrency().equals(money.getCurrency())){
+           throw new InvalidCurrencyException();
+       }
+
+       this.available = this.available.add(money);
+
+    }
+}

bank-domain/src/main/java/com/example/bank/domain/service/AccountTransferService.java

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+package com.example.bank.domain.service;
+
+import com.example.bank.domain.entity.Account;
+import com.example.bank.exception.DailyLimitExceededException;
+import com.example.bank.exception.InsufficientFundsException;
+import com.example.bank.exception.InvalidCurrencyException;
+import com.example.bank.types.ExchangeRate;
+import com.example.bank.types.Money;
+
+public interface AccountTransferService {
+    void transfer(Account sourceAccount, Account targetAccount, Money targetMoney, ExchangeRate exchangeRate) throws Exception, DailyLimitExceededException;
+}

bank-domain/src/main/java/com/example/bank/domain/service/impl/AccountTransferServiceImpl.java

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+package com.example.bank.domain.service.impl;
+
+import com.example.bank.domain.entity.Account;
+import com.example.bank.domain.service.AccountTransferService;
+import com.example.bank.exception.DailyLimitExceededException;
+import com.example.bank.exception.InsufficientFundsException;
+import com.example.bank.exception.InvalidCurrencyException;
+import com.example.bank.types.ExchangeRate;
+import com.example.bank.types.Money;
+import org.springframework.stereotype.Service;
+
+@Service
+public class AccountTransferServiceImpl implements AccountTransferService {
+    @Override
+    public void transfer(Account sourceAccount, Account targetAccount, Money targetMoney, ExchangeRate exchangeRate) throws Exception, DailyLimitExceededException {
+        Money sourceMoney =  exchangeRate.exchageTo(targetMoney);
+        sourceAccount.deposit(sourceMoney);
+        targetAccount.withdraw(targetMoney);
+    }
+}

bank-domain/src/main/java/com/example/bank/domain/types/AuditMessage.java

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+package com.example.bank.domain.types;
+
+import com.example.bank.domain.entity.Account;
+import com.example.bank.types.Money;
+
+public class AuditMessage {
+    public AuditMessage(Account sourceAccount, Account targetAccount, Money targetMoney) {
+
+    }
+}

bank-domain/src/main/java/com/example/bank/exception/AccountNotFoundException.java

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+package com.example.bank.exception;
+
+public class AccountNotFoundException {
+}

bank-domain/src/main/java/com/example/bank/exception/DailyLimitExceededException.java

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+package com.example.bank.exception;
+
+public class DailyLimitExceededException extends Throwable {
+}

bank-domain/src/main/java/com/example/bank/exception/InsufficientFundsException.java

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+package com.example.bank.exception;
+
+public class InsufficientFundsException extends Exception{
+}

bank-domain/src/main/java/com/example/bank/external/ExchangeRateService.java

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+package com.example.bank.external;
+
+import com.example.bank.types.Currency;
+import com.example.bank.types.ExchangeRate;
+
+public interface ExchangeRateService {
+    ExchangeRate getExchangeRate(Currency source, Currency target);
+
+}
+

bank-domain/src/main/java/com/example/bank/messaging/AuditMessageProducer.java

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+package com.example.bank.messaging;
+
+import com.example.bank.domain.types.AuditMessage;
+
+public interface AuditMessageProducer {
+    void send(AuditMessage message);
+}

bank-domain/src/main/java/com/example/bank/repository/AccountRepository.java

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+package com.example.bank.repository;
+
+import com.example.bank.domain.entity.Account;
+import com.example.bank.types.AccountId;
+import com.example.bank.types.AccountNumber;
+import com.example.bank.types.UserId;
+
+public interface AccountRepository {
+    Account find(AccountId id) throws Exception;
+    Account find(AccountNumber accountNumber) throws Exception;
+    Account find(UserId userId) throws Exception;
+    Account save(Account account) throws Exception;
+}

bank-persistence/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <parent>
+        <artifactId>dddbook</artifactId>
+        <groupId>com.example</groupId>
+        <version>1.0-SNAPSHOT</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>bank-persistence</artifactId>
+
+
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>com.example</groupId>
+            <artifactId>bank-domain</artifactId>
+            <version>${dddbook.version}</version>
+            <scope>compile</scope>
+        </dependency>
+    </dependencies>
+</project>

bank-persistence/src/main/java/com/example/bank/external/ExchangeRateServiceImpl.java

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+package com.example.bank.external;
+
+import com.example.bank.types.Currency;
+import com.example.bank.types.ExchangeRate;
+import org.springframework.stereotype.Service;
+
+import java.math.BigDecimal;
+
+@Service
+public class ExchangeRateServiceImpl implements ExchangeRateService{
+    @Override
+    public ExchangeRate getExchangeRate(Currency source, Currency target) {
+//        if (source.equals(target)) {
+            return new ExchangeRate(BigDecimal.ONE, source, target);
+//        }
+
+    }
+}

bank-persistence/src/main/java/com/example/bank/persistence/AccountBuilder.java

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+package com.example.bank.persistence;
+
+import com.example.bank.domain.entity.Account;
+
+public interface AccountBuilder {
+    Account toAccount(AccountDO accountDO) throws Exception;
+
+    AccountDO fromAccount(Account account);
+}