综述：项目需求，补充学习了Spring AOP，练习了小项目，出现的问题记录备忘一下。
备忘列表
导入的Jar包列表以及applicationContext.xml示例约束文件schema添加@Before JoinPoint的jar包各种通知总结多个通知的优先级切入点表达式
导入的Jar包列表以及applicationContext.xml示例
applicationContext.xml示例
<?xml version=
"1.0" encoding=
"UTF-8"?>
<beans xmlns=
"http://www.springframework.org/schema/beans"
xmlns:xsi=
"http://www.w3.org/2001/XMLSchema-instance"
xmlns:context=
"http://www.springframework.org/schema/context"
xmlns:aop=
"http://www.springframework.org/schema/aop"
xsi:schemaLocation=
"http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop.xsd">
<context:component-scan base-
package=
"tqj.springAOP.day_01.b"></context:component-scan>
<!-- 使AspectJ 起作用 :自动为匹配的类生成代理对象-->
<aop:aspectj-autoproxy></aop:aspectj-autoproxy>
</beans>
约束文件schema添加
约束文件位置：spring-framework-4.0.3.RELEASE-docs\spring-framework-reference\html\xsd-config.html
@Before
@Before(
"execution(public int tqj.springAOP.day_01.b.MathematicCalculatorImpl.add(int, int))")
主要是强调一下 public int，不加会出现错误。
或者，更通用一些：
@Before(
"execution(* tqj.springAOP.day_01.b.MathematicCalculatorImpl.*(..))")
JoinPoint的jar包
写 ` String methodName = joinpoint.getSignature().getName()` 的时候找不到**.getSianature()**方法，发现导入的Jar包不对，应该导入的是以下的Jar包
import org.aspectj.lang.JoinPoint;
各种通知总结
@Before(
"execution(public int tqj.springAOP.day_01.b.MathematicCalculatorImpl.*(..))")
public void before(JoinPoint joinpoint){
String methodName = joinpoint.getSignature().getName();
List<Object> args = Arrays.asList(joinpoint.getArgs());
System.out.println(
"The method " + methodName +
" begins with " + args);
}
@After(
"execution(* tqj.springAOP.day_01.b.MathematicCalculatorImpl.*(..))")
public void after(JoinPoint joinpoint){
String methodName = joinpoint.getSignature().getName();
System.out.println(
"The method " + methodName +
" ends.");
}
@AfterReturning(value=
"execution(* tqj.springAOP.day_01.b.MathematicCalculatorImpl.*(..))",returning =
"result")
public void afterReturning(JoinPoint joinPoint, Object result){
String methodName = joinPoint.getSignature().getName();
System.out.println(
"The method " + methodName +
" ends with " + result);
}
@AfterThrowing(value=
"execution(* tqj.springAOP.day_01.b.MathematicCalculatorImpl.*(..))",throwing =
"ex")
public void afterThrowing(JoinPoint joinPoint, Exception ex){
String methodName = joinPoint.getSignature().getName();
System.out.println(
"The method " + methodName +
" occurs " + ex);}
/**
* 环绕通知需要携带 ProdeedingJointPoint 类型的参数
* 类似于动态代理的全过程： ProdeedingJointPoint 类型的参数可以决定是否执行目标方法
* 且环绕通知必须有返回值，返回值即为目标方法的返回值
*/
@Around(
"execution(* tqj.springAOP.day_01.b.MathematicCalculatorImpl.*(..))")
public Object
aroundMethod(ProceedingJoinPoint pjd){
Object result =
null;
String methodName = pjd.getSignature().getName();
try {
System.out.println(
"The method " + methodName +
" begins with " + Arrays.asList(pjd.getArgs()));
result = pjd.proceed();
System.out.println(
"The method ends with " + result);
}
catch (Throwable e) {
System.out.println(
"The method occurs exception" + e);
}
System.out.println(
"The method " + methodName +
" ends.");
return result;
};
多个通知的优先级
使用@Order(数字)，括号里的数字越小，优先级越高
切入点表达式
/**
* 定义一个方法，用于声明切入点表达式，一般地，该方法中不需要添加其他代码
*/
@Pointcut(
"execution(public int tqj.springAOP.day_01.b.MathematicCalculatorImpl.*(..))")
public void declareJoinPointExpression(){}
@Before(
"declareJoinPointion()")
public void before(JoinPoint joinpoint){
String methodName = joinpoint.getSignature().getName();
List<Object> args = Arrays.asList(joinpoint.getArgs());
System.out.println(
"The method " + methodName +
" begins with " + args); }
public class ValidationAspect {
@Before(
"tqj.springAOP.day_01.b.LoggingAspect.declareJoinPointExpression()")
public void validate(){
System.out.println(
"Validate --> ");
}
}
