本身動手實現RPC

1、需求：用戶管理系統（UMS）,倉庫管理系統（WMS），訂單管理系統（OMS）

如今OMS有一張訂單表：【訂單id，用戶id，商品id,訂單狀態，訂單時間】，須要在客戶端展現此訂單對應的用戶詳情和商品詳情

2、接口API整理：在OMS中，須要根據用戶id在UMS中查詢用戶詳情和根據商品id在WMS中查詢商品詳情

1.User selectUserById(long id)

2.Product selectProductById(long id)

3、接口調用架構圖：

4、代碼實現

 1.工程結構

2.代碼實現

// OMS系統代碼
public class Order {
    private Long id;
    // 商品id
    private Long productId;
    // 用戶id
    private Long userId;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public Long getProductId() {
        return productId;
    }

    public void setProductId(Long productId) {
        this.productId = productId;
    }

    public Long getUserId() {
        return userId;
    }

    public void setUserId(Long userId) {
        this.userId = userId;
    }

    @Override
    public String toString() {
        return "Order{" +
                "id=" + id +
                ", productId=" + productId +
                ", userId=" + userId +
                '}';
    }
}

public class OrderService {
    public Order selectOrderById(long id){
        Order order = new Order();
        order.setId(id);
        order.setUserId(1l);
        order.setProductId(1L);
        return order;
    }
}

public class Main {
    public static void main(String[] args) {
        // 獲取訂單詳情
        OrderService orderService = new OrderService();
        Order order = orderService.selectOrderById(1L);
        System.out.println("訂單信息：" + order);
        // 根據商品id獲取商品
        ProductService productService = (ProductService) rpcHandle(ProductService.class, "127.0.0.1", 8888);
        Product product = productService.selectProductById(order.getProductId());
        System.out.println("商品信息：" + product);
        // 根據用戶id獲取用戶
        UserService userService = (UserService) rpcHandle(UserService.class, "127.0.0.1", 9999);
        User user = userService.selectUserById(order.getUserId());
        System.out.println("用戶信息：" + user);
    }

    /**
     * RPC遠程調用實現
     */
    public static Object rpcHandle(final Class clazz, final String host, final int port) {
        return Proxy.newProxyInstance(clazz.getClassLoader(),
                new Class[]{clazz}, new InvocationHandler() {
                    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
                        Socket socket = new Socket(host, port);
                        // 想要調用遠程類的某個方法，必需要知道類名稱，方法名稱，參數類型，參數
                        String apiClassName = clazz.getName();
                        String methodName = method.getName();
                        Class[] parameterTypes = method.getParameterTypes();
                        ObjectOutputStream objectOutputStream = new ObjectOutputStream(socket.getOutputStream());
                        objectOutputStream.writeUTF(apiClassName);
                        objectOutputStream.writeUTF(methodName);
                        objectOutputStream.writeObject(parameterTypes);
                        objectOutputStream.writeObject(args);
                        objectOutputStream.flush();

                        ObjectInputStream objectInputStream = new ObjectInputStream(socket.getInputStream());
                        Object object = objectInputStream.readObject();
                        if (null != objectInputStream ){
                            objectInputStream.close();
                        }
                        if (null != objectOutputStream){
                            objectOutputStream.close();
                        }
                        if (null != socket){
                            socket.close();
                        }
                        return object;
                    }
                }
        );
    }
}

// WMS代碼
public class Product implements Serializable {
    private Long id;
    private String name;
    private Double price;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Double getPrice() {
        return price;
    }

    public void setPrice(Double price) {
        this.price = price;
    }

    @Override
    public String toString() {
        return "Product{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", price=" + price +
                '}';
    }
}

public interface ProductService {

    /**
     * 根據商品ID查詢商品信息
     *
     * @param id：商品id
     * @return
     */
    Product selectProductById(long id);
}

public class ProductServiceImpl implements ProductService {
    public Product selectProductById(long id) {
        Product product = new Product();
        product.setId(id);
        product.setName("CAMEL運動鞋");
        product.setPrice(299.0);
        return product;
    }
}

public class Main {
    public static void main(String[] args) {
        try {
            ServerSocket serverSocket = new ServerSocket(8888);
            while (true) {
                Socket socket = serverSocket.accept();
                ObjectInputStream objectInputStream = new ObjectInputStream(socket.getInputStream());
                // 讀取網絡協議
                String apiClassName = objectInputStream.readUTF();
                String methodName = objectInputStream.readUTF();
                Class[] parameterTypes = (Class[]) objectInputStream.readObject();
                Object[] argsMethod = (Object[]) objectInputStream.readObject();

                Class clazz = null;
                // 服務註冊：API到具體實現的映射關係
                if (apiClassName.equals(ProductService.class.getName())) {
                    clazz = ProductServiceImpl.class;
                }
                ObjectOutputStream objectOutputStream = null;
                if (null != clazz) {
                    Method method = clazz.getMethod(methodName, parameterTypes);
                    Object invoke = method.invoke(clazz.newInstance(), argsMethod);
                    objectOutputStream = new ObjectOutputStream(socket.getOutputStream());
                    objectOutputStream.writeObject(invoke);
                    objectOutputStream.flush();
                }
                // 關閉資源
                if (null != objectInputStream) {
                    objectInputStream.close();
                }
                if (null != objectOutputStream) {
                    objectOutputStream.close();
                }
                if (null != socket) {
                    socket.close();
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

// UUMS代碼
public class User implements Serializable {
    private Long id;
    private String name;
    private Integer age;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", age='" + age + '\'' +
                '}';
    }
}

public interface UserService {

    /**
     * 根據用戶id，查詢用戶
     * @param id:用戶id
     * @return
     */
    User selectUserById(Long id);
}

public class UserServiceImpl implements UserService {
    public User selectUserById(Long id) {
        User user = new User();
        user.setId(id);
        user.setName("Jack Tang");
        user.setAge(20);
        return user;
    }
}

public class UserServiceImpl implements UserService {
    public User selectUserById(Long id) {
        User user = new User();
        user.setId(id);
        user.setName("Jack Tang");
        user.setAge(20);
        return user;
    }
}

public class Main {
    public static void main(String[] args) {
        try {
            ServerSocket serverSocket = new ServerSocket(9999);
            while (true) {
                Socket socket = serverSocket.accept();
                ObjectInputStream objectInputStream = new ObjectInputStream(socket.getInputStream());
                String apiClassName = objectInputStream.readUTF();
                String methodName = objectInputStream.readUTF();
                Class[] parameterTypes = (Class[]) objectInputStream.readObject();
                Object[] argsMethod = (Object[]) objectInputStream.readObject();

                Class clazz = null;
                if (apiClassName.equals(UserService.class.getName())){
                    clazz = UserServiceImpl.class;
                }
                ObjectOutputStream objectOutputStream = null;
                if (null != clazz) {
                    Method method = clazz.getMethod(methodName, parameterTypes);
                    Object invoke = method.invoke(clazz.newInstance(), argsMethod);
                    objectOutputStream = new ObjectOutputStream(socket.getOutputStream());
                    objectOutputStream.writeObject(invoke);
                    objectOutputStream.flush();
                }
                // 關閉資源
                if (null != objectInputStream) {
                    objectInputStream.close();
                }
                if (null != objectOutputStream) {
                    objectOutputStream.close();
                }
                if (null != socket) {
                    socket.close();
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}