公共字段自动填充：AOP切面//反射

sky-server/src/main/java/com/sky/annotation/AutoFill.java

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+package com.sky.annotation;
+
+import com.sky.enumeration.OperationType;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * 用于标识方法需要进行字段的自动填充处理
+ */
+@Target(ElementType.METHOD)
+@Retention(RetentionPolicy.RUNTIME)
+public @interface AutoFill {
+    //指定数据库操作类型
+    OperationType value();
+}

sky-server/src/main/java/com/sky/aspect/AutoFillAspect.java

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+package com.sky.aspect;
+
+import com.sky.annotation.AutoFill;
+import com.sky.constant.AutoFillConstant;
+import com.sky.context.BaseContext;
+import com.sky.enumeration.OperationType;
+import lombok.extern.slf4j.Slf4j;
+import org.aspectj.lang.JoinPoint;
+import org.aspectj.lang.Signature;
+import org.aspectj.lang.annotation.Aspect;
+import org.aspectj.lang.annotation.Before;
+import org.aspectj.lang.annotation.Pointcut;
+import org.aspectj.lang.reflect.MethodSignature;
+import org.springframework.stereotype.Component;
+
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.time.LocalDateTime;
+
+/**
+ * 公共字段自动填充切面
+ */
+@Aspect
+@Component
+@Slf4j
+public class AutoFillAspect {
+    /**
+     * 切入点
+     */
+    @Pointcut("execution(* com.sky.mapper.*.*(..)) && @annotation(com.sky.annotation.AutoFill)")
+    public void autoFillPointCut() {
+    }
+
+    /**
+     * 公共字段赋值
+     */
+    @Before("autoFillPointCut()")
+    public void autoFill(JoinPoint joinPoint)  {
+        log.info("开始进行公共字段的自动填充...");
+
+        //获取当前被拦截的方法的数据库操作类型
+        MethodSignature signature = (MethodSignature) joinPoint.getSignature();//方法签名对象
+        AutoFill autoFill = signature.getMethod().getAnnotation(AutoFill.class);//获取注解
+        OperationType operationType = autoFill.value();//获取操作类型
+
+        //获取参数--实体对象
+        Object[] args = joinPoint.getArgs();
+        if (args == null || args.length == 0) {
+            return;
+        }
+        Object entity = args[0];
+
+        //准备赋值的数据
+        LocalDateTime now = LocalDateTime.now();
+        Long currentId = BaseContext.getCurrentId();
+
+        //根据操作类型赋值
+        if (operationType == OperationType.INSERT) {
+            try {
+                Method setCreateTime = entity.getClass().getDeclaredMethod(AutoFillConstant.SET_CREATE_TIME, LocalDateTime.class);
+                Method setCreateUser = entity.getClass().getDeclaredMethod(AutoFillConstant.SET_CREATE_USER, Long.class);
+                Method setUpdateTime = entity.getClass().getDeclaredMethod(AutoFillConstant.SET_UPDATE_TIME, LocalDateTime.class);
+                Method setUpdateUser = entity.getClass().getDeclaredMethod(AutoFillConstant.SET_UPDATE_USER, Long.class);
+
+                //通过反射赋值
+                setCreateTime.invoke(entity,now);
+                setCreateUser.invoke(entity,currentId);
+                setUpdateTime.invoke(entity,now);
+                setUpdateUser.invoke(entity,currentId);
+            } catch (NoSuchMethodException | IllegalAccessException | InvocationTargetException e) {
+                throw new RuntimeException(e);
+            }
+        }else if (operationType == OperationType.UPDATE) {
+            try {
+                Method setUpdateTime = entity.getClass().getDeclaredMethod(AutoFillConstant.SET_UPDATE_TIME, LocalDateTime.class);
+                Method setUpdateUser = entity.getClass().getDeclaredMethod(AutoFillConstant.SET_UPDATE_USER, Long.class);
+
+                //通过反射赋值
+                setUpdateTime.invoke(entity,now);
+                setUpdateUser.invoke(entity,currentId);
+            } catch (NoSuchMethodException | InvocationTargetException | IllegalAccessException e) {
+                throw new RuntimeException(e);
+            }
+        }
+    }
+}