静态代理实现

src/main/java/top/fjy8018/designpattern/pattern/structural/proxy/IOrderDao.java

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+package top.fjy8018.designpattern.pattern.structural.proxy;
+
+/**
+ * DAO层——与业务无关
+ * 仿mybatis
+ *
+ * @author F嘉阳
+ * @date 2020/2/29 16:15
+ */
+public interface IOrderDao {
+
+    int insert(Order order);
+}

src/main/java/top/fjy8018/designpattern/pattern/structural/proxy/IOrderDaoImpl.java

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+package top.fjy8018.designpattern.pattern.structural.proxy;
+
+import lombok.extern.slf4j.Slf4j;
+
+/**
+ * @author F嘉阳
+ * @date 2020/2/29 16:17
+ */
+@Slf4j
+public class IOrderDaoImpl implements IOrderDao {
+    @Override
+    public int insert(Order order) {
+        log.info("DAO层添加订单记录成功");
+        return 1;
+    }
+}

src/main/java/top/fjy8018/designpattern/pattern/structural/proxy/IOrderService.java

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+package top.fjy8018.designpattern.pattern.structural.proxy;
+
+/**
+ * 订单服务层
+ *
+ * @author F嘉阳
+ * @date 2020/2/29 16:14
+ */
+public interface IOrderService {
+
+    /**
+     * 保存订单
+     *
+     * @param order
+     * @return 保存的行数
+     */
+    int save(Order order);
+}

src/main/java/top/fjy8018/designpattern/pattern/structural/proxy/IOrderServiceImpl.java

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+package top.fjy8018.designpattern.pattern.structural.proxy;
+
+import lombok.extern.slf4j.Slf4j;
+
+/**
+ * @author F嘉阳
+ * @date 2020/2/29 16:16
+ */
+@Slf4j
+public class IOrderServiceImpl implements IOrderService {
+
+    /**
+     * 模拟Spring注入
+     */
+    private IOrderDao orderDao = new IOrderDaoImpl();
+
+    /**
+     * 保存订单
+     *
+     * @param order
+     * @return 保存的行数
+     */
+    @Override
+    public int save(Order order) {
+        log.info("Service层调用DAO层添加订单记录成功");
+        return orderDao.insert(order);
+    }
+}

src/main/java/top/fjy8018/designpattern/pattern/structural/proxy/Order.java

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+package top.fjy8018.designpattern.pattern.structural.proxy;
+
+import lombok.Getter;
+import lombok.Setter;
+
+/**
+ * 订单
+ *
+ * @author F嘉阳
+ * @date 2020/2/29 16:12
+ */
+@Getter
+@Setter
+public class Order {
+
+    private Object orderInfo;
+
+    private Integer userId;
+}

src/main/java/top/fjy8018/designpattern/pattern/structural/proxy/staticproxy/OrderServiceStaticProxy.java

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+package top.fjy8018.designpattern.pattern.structural.proxy.staticproxy;
+
+import lombok.extern.slf4j.Slf4j;
+import top.fjy8018.designpattern.pattern.structural.proxy.IOrderService;
+import top.fjy8018.designpattern.pattern.structural.proxy.IOrderServiceImpl;
+import top.fjy8018.designpattern.pattern.structural.proxy.Order;
+import top.fjy8018.designpattern.pattern.structural.proxy.db.DataSourceContextHolder;
+
+/**
+ * 静态代理实现分库
+ *
+ * @author F嘉阳
+ * @date 2020/2/29 16:20
+ */
+@Slf4j
+public class OrderServiceStaticProxy {
+
+    /**
+     * 模拟Spring注入
+     */
+    private IOrderService orderService = new IOrderServiceImpl();
+
+    /**
+     * 对源方法增强
+     *
+     * @param order
+     * @return
+     */
+    public int save(Order order) {
+        beforeMethod();
+
+        // 通过用户ID对2取模分库
+        Integer userId = order.getUserId();
+        int dbRouter = userId % 2;
+        log.info("静态代理分配到【db{}】处理数据", dbRouter);
+
+        // 设置DataSource
+        DataSourceContextHolder.setDBType(String.valueOf(dbRouter));
+
+        afterMethod();
+
+        return orderService.save(order);
+    }
+
+    private void beforeMethod() {
+        log.info("静态代理before code");
+    }
+
+    private void afterMethod() {
+        log.info("静态代理after code");
+    }
+}

src/test/java/top/fjy8018/designpattern/pattern/structural/proxy/staticproxy/OrderServiceStaticProxyTest.java

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+package top.fjy8018.designpattern.pattern.structural.proxy.staticproxy;
+
+import lombok.extern.slf4j.Slf4j;
+import org.junit.jupiter.api.Test;
+import top.fjy8018.designpattern.pattern.structural.proxy.Order;
+
+/**
+ * @author F嘉阳
+ * @date 2020/2/29 17:17
+ */
+@Slf4j
+class OrderServiceStaticProxyTest {
+
+    @Test
+    void save() {
+        Order order1 = new Order();
+        order1.setUserId(1);
+        Order order2 = new Order();
+        order2.setUserId(2);
+
+        OrderServiceStaticProxy proxy = new OrderServiceStaticProxy();
+        proxy.save(order1);
+        proxy.save(order2);
+    }
+}