本篇文章給大家分享的是有關@AspectJ怎么在Spring AOP 中使用,小編覺得挺實用的,因此分享給大家學習,希望大家閱讀完這篇文章后可以有所收獲,話不多說,跟著小編一起來看看吧。

@AspectJ可以使用切點函數定義切點,我們還可以使用邏輯運算符對切點進行復核運算得到復合的切點,為了在切面中重用切點,我們還可以對切點進行命名,以便在其他的地方引用定義過的切點。
當一個連接點匹配多個切點時,需要考慮織入順序的問題,此外一個重要的問題是如何再增強中訪問連接點上下文的信息。
Waiter接口:
package com.yyq.aspectJAdvanced;
public interface Waiter {
void greetTo(String name);
void serveTo(String name);
}NaiveWaiter實現類:
package com.yyq.aspectJAdvanced;
public class NaiveWaiter implements Waiter {
@Override
public void greetTo(String name) {
System.out.println("NaiveWaiter:greet to " + name + "...");
}
@Override
public void serveTo(String name) {
System.out.println("NaiveWaiter:serving to " + name + "...");
}
public void smile(String clientName,int times){
System.out.println("NaiveWaiter:smile to "+clientName+ times+"times...");
}
}NaughtyWaiter實現類:
package com.yyq.aspectJAdvanced;
public class NaughtyWaiter implements Waiter {
public void greetTo(String clientName) {
System.out.println("NaughtyWaiter:greet to " + clientName + "...");
}
public void serveTo(String clientName) {
System.out.println("NaughtyWaiter:serving " + clientName + "...");
}
public void joke(String clientName, int times) {
System.out.println("NaughtyWaiter:play " + times + " jokes to " + clientName + "...");
}
}Seller接口:
package com.yyq.aspectJAdvanced;
public interface Seller {
int sell(String goods, String clientName);
}SmallSeller實現類:
package com.yyq.aspectJAdvanced;
public class SmartSeller implements Seller {
public int sell(String goods,String clientName) {
System.out.println("SmartSeller: sell "+goods +" to "+clientName+"...");
return 100;
}
public void checkBill(int billId){
if(billId == 1) throw new IllegalArgumentException("iae Exception");
else throw new RuntimeException("re Exception");
}
}beans.xml配置文件:
<?xml version="1.0" encoding="UTF-8" ?> <beans xmlns="/tupian/20230522/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="/tupian/20230522/" xsi:schemaLocation="/tupian/20230522/ /tupian/20230522//spring-beans-3.0.xsd /tupian/20230522/ /tupian/20230522//spring-aop-3.0.xsd"> <aop:aspectj-autoproxy proxy-target-class="true"/> <bean id="naiveWaiter" class="com.yyq.aspectJAdvanced.NaiveWaiter"/> <bean id="naughtyWaiter" class="com.yyq.aspectJAdvanced.NaughtyWaiter"/> <bean id="seller" class="com.yyq.aspectJAdvanced.SmartSeller"/> <!-- <bean class="com.yyq.aspectJAdvanced.TestAspect"/> <bean class="com.yyq.aspectJAdvanced.TestAspect2"/> <bean class="com.yyq.aspectJAdvanced.TestAspect3"/> <bean class="com.yyq.aspectJAdvanced.TestAspect4"/> <bean class="com.yyq.aspectJAdvanced.TestAspect5"/> <bean id="naiveWaiter2" class="com.yyq.aspectJAdvanced.NaiveWaiter2"/> <bean class="com.yyq.aspectJAdvanced.TestAspect6"/> <bean class="com.yyq.aspectJAdvanced.TestAspect7"/> <bean class="com.yyq.aspectJAdvanced.TestAspect8"/> --> </beans>
使用切點符合運算符,我們將擁有強大而靈活的切點表達能力。
TestAspect:切點符合運算定義切面
package com.yyq.aspectJAdvanced;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.AfterReturning;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
@Aspect
public class TestAspect {
//與非運算
@Before("!target(com.yyq.aspectJAdvanced.NaiveWaiter) && execution(* serveTo(..))")
public void notServeInNaiveWaiter(){
System.out.println("--notServeInNaiveWaiter() executed!--");
}
//與運算
@After("within(com.yyq.aspectJAdvanced.*) && execution(* greetTo(..))")
public void greetToFun(){
System.out.println("--greetToFun() executed!--");
}
//或運算
@AfterReturning("target(com.yyq.aspectJAdvanced.Waiter) || target(com.yyq.aspectJAdvanced.Seller)")
public void waiterOrSeller(){
System.out.println("--waiterOrSeller() executed!--");
}
}測試方法:
@Test
public void pointAspectJTest() {
String configPath = "com\\yyq\\aspectJAdvanced\\beans.xml";
ApplicationContext ctx = new ClassPathXmlApplicationContext(configPath);
Waiter naiveWaiter = (Waiter) ctx.getBean("naiveWaiter");
Waiter naughtyWaiter = (Waiter) ctx.getBean("naughtyWaiter");
naiveWaiter.greetTo("John");
naiveWaiter.serveTo("John");
naughtyWaiter.greetTo("Tom");
naughtyWaiter.serveTo("Tom");
}輸出結果:
NaiveWaiter:greet to John... --greetToFun() executed!-- --waiterOrSeller() executed!-- NaiveWaiter:serving to John... --waiterOrSeller() executed!-- NaughtyWaiter:greet to Tom... --greetToFun() executed!-- --waiterOrSeller() executed!-- --notServeInNaiveWaiter() executed!-- NaughtyWaiter:serving Tom... --waiterOrSeller() executed!--
切點直接聲明在增強方法處被稱為匿名切點,匿名切點只能在聲明處使用。如果希望在其他地方重用一個切點,我們可以通過@Pointcut注解以及切面類方法對切點進行命名。
TestNamePointcut:命名切點類
package com.yyq.aspectJAdvanced;
import org.aspectj.lang.annotation.Pointcut;
public class TestNamePointcut {
//通過注解方法inPackage()對該切點進行命名,方法可視域修飾符為private,表明該命名切點只能在本切面類中使用
@Pointcut("within(com.yyq.aspectJAdvaned.*)")
private void inPackage(){}
@Pointcut("execution(* greetTo(..))")
protected void greetTo(){}
@Pointcut("inPackage() and greetTo()")
public void inPkgGreetTo(){}
}TestAspect2:切面實現類
package com.yyq.aspectJAdvanced;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
@Aspect
public class TestAspect2 {
@Before("TestNamePointcut.inPkgGreetTo()")
public void pkgGreetTo(){
System.out.println("--pkgGreetTo() executed!--");
}
@Before("target(com.yyq.aspectJAdvanced.NaiveWaiter) || TestNamePointcut.inPkgGreetTo()")
public void pkgGreetToNotnaiveWaiter(){
System.out.println("--pkgGreetToNotnaiveWaiter() executed!--");
}
}測試方法:
@Test
public void pointAspectJTest2() {
String configPath = "com\\yyq\\aspectJAdvanced\\beans.xml";
ApplicationContext ctx = new ClassPathXmlApplicationContext(configPath);
NaiveWaiter naiveWaiter = (NaiveWaiter) ctx.getBean("naiveWaiter");
naiveWaiter.smile("Andy", 2);
}輸出結果:
--pkgGreetToNotnaiveWaiter() executed!-- NaiveWaiter:smile to Andy2times...
一個連接點可以同時匹配多個切點,切點對應的增強在連接點上的織入順序的安排主要有以下3種情況:
1)如果增強在同一個切面類中聲明,則依照增強在切面類中定義的順序進行織入;
2)如何增強位于不同的切面類中,且這些切面類都實現了org.springframework.core.Order接口,則由接口方法的順序號決定(順序號小的先織入);
3)如果增強位于不同的切面類中,且這些切面類沒有實現org.springframework.core.Order接口,織入的順序是不確定的。
AspectJ使用org.aspectj.lang.JoinPoint接口表示目標類連接點對象,如果是環(huán)繞增強時,使用org.aspectj.lang.ProceedingJoinPoint表示連接點對象,該類是JoinPoint的子接口,任何一個增強方法都可以通過將第一個入參聲明為JoinPoint訪問到連接點上下文的信息。
TestAspect3:切面實現類
@Aspect
public class TestAspect3 {
@Around("execution(* greetTo(..)) && target(com.yyq.aspectJAdvanced.NaiveWaiter)")
public void joinPointAccess(ProceedingJoinPoint pjp) throws Throwable {
System.out.println("---joinPointAccess---");
System.out.println("args[0]:" + pjp.getArgs()[0]);
System.out.println("signature:" + pjp.getTarget().getClass());
pjp.proceed();
System.out.println("---joinPointAccess---");
}
}測試方法:
@Test
public void pointAspectJTest3() {
String configPath = "com\\yyq\\aspectJAdvanced\\beans.xml";
ApplicationContext ctx = new ClassPathXmlApplicationContext(configPath);
Waiter naiveWaiter = (Waiter) ctx.getBean("naiveWaiter");
naiveWaiter.greetTo("Andy");
}輸出結果:
---joinPointAccess--- args[0]:Andy signature:class com.yyq.aspectJAdvanced.NaiveWaiter NaiveWaiter:greet to Andy... ---joinPointAccess---
args()用于綁定連接點方法的入參;@annotation()用于綁定連接點方法的注解對象;而@args()用于綁定連接點方法入參的注解。
TestAspect4:切面實現類
@Aspect
public class TestAspect4 {
@Before("target(com.yyq.aspectJAdvanced.NaiveWaiter) && args(name,num,..)")
public void bindJoinPointParams(int num, String name) {
System.out.println("---bindJoinPointParams---");
System.out.println("name:" + name);
System.out.println("num:" + num);
System.out.println("---bindJoinPointParams---");
}
}測試方法:
@Test
public void pointAspectJTest4() {
String configPath = "com\\yyq\\aspectJAdvanced\\beans.xml";
ApplicationContext ctx = new ClassPathXmlApplicationContext(configPath);
NaiveWaiter naiveWaiter = (NaiveWaiter) ctx.getBean("naiveWaiter");
naiveWaiter.smile("Andy", 3);
}輸出結果:
---bindJoinPointParams--- name:Andy num:3 ---bindJoinPointParams--- NaiveWaiter:smile to Andy 3 times...
使用this()或target()可綁定被代理對象實例,在通過類實例名綁定對象時,還依然具有原來連接點匹配的功能,只不過類名是通過增強方法中同名入參的類型間接決定罷了。
TestAspect5:切面實現類
@Aspect
public class TestAspect5 {
@Before("this(waiter)")
public void bindProxyObj(Waiter waiter){
System.out.println("---bindProxyObj---");
System.out.println(waiter.getClass().getName());
System.out.println("---bindProxyObj---");
}
}測試方法:
@Test
public void pointAspectJTest5() {
String configPath = "com\\yyq\\aspectJAdvanced\\beans.xml";
ApplicationContext ctx = new ClassPathXmlApplicationContext(configPath);
Waiter waiter = (Waiter) ctx.getBean("naiveWaiter");
waiter.greetTo("Yang");
}輸出結果:
---bindProxyObj--- com.yyq.aspectJAdvanced.NaiveWaiter$$EnhancerByCGLIB$$fefafe52 ---bindProxyObj--- NaiveWaiter:greet to Yang...
@within()和@target()函數可以將目標類的注解對象綁定到增強方法中,我們通過@within()演示注解綁定的操作。
TestAspect6:切面測試類
@Aspect
public class TestAspect6 {
@Before("@within(m)")
public void bindTypeAnnoObject(Monitorable m) {
System.out.println("---bindTypeAnnoObject---");
System.out.println(m.getClass().getName());
System.out.println("---bindTypeAnnoObject---");
}
}測試方法:
@Test
public void pointAspectJTest6() {
String configPath = "com\\yyq\\aspectJAdvanced\\beans.xml";
ApplicationContext ctx = new ClassPathXmlApplicationContext(configPath);
Waiter waiter = (Waiter) ctx.getBean("naiveWaiter2");
((NaiveWaiter2)waiter).greetTo("Yang");
}輸出結果:
---bindTypeAnnoObject--- $Proxy4 ---bindTypeAnnoObject--- NaiveWaiter:greet to Yang...
在后置增強中,我們可以通過returning綁定連接點方法的返回值。
TestAspect7:切面實現類
@Aspect
public class TestAspect7 {
@AfterReturning(value = "target(com.yyq.aspectJAdvanced.SmartSeller)", returning = "retVal")
public void bindReturnValue(int retVal) {
System.out.println("---bindReturnValue---");
System.out.println("returnValue:" + retVal);
System.out.println("---bindReturnValue---");
}
}測試方法:
@Test
public void pointAspectJTest7() {
String configPath = "com\\yyq\\aspectJAdvanced\\beans.xml";
ApplicationContext ctx = new ClassPathXmlApplicationContext(configPath);
SmartSeller seller = (SmartSeller) ctx.getBean("seller");
seller.sell("Beer", "John");
}輸出結果:
SmartSeller: sell Beer to John... ---bindReturnValue--- returnValue:100 ---bindReturnValue---
和通過切點函數綁定連接點信息不同,連接點拋出的異常必須使用AfterThrowing注解的throwing成員進行綁定。
TestAspect8:切面實現類
@Aspect
public class TestAspect8 {
@AfterThrowing(value = "target(com.yyq.aspectJAdvanced.SmartSeller)", throwing = "iae")
public void bindException(IllegalArgumentException iae) {
System.out.println("---bindException---");
System.out.println("exception:" + iae.getMessage());
System.out.println("---bindException---");
}
}測試方法:
@Test
public void pointAspectJTest8() {
String configPath = "com\\yyq\\aspectJAdvanced\\beans.xml";
ApplicationContext ctx = new ClassPathXmlApplicationContext(configPath);
SmartSeller seller = (SmartSeller) ctx.getBean("seller");
seller.checkBill(1);
}輸出結果:
---bindException--- exception:iae Exception ---bindException---
以上就是@AspectJ怎么在Spring AOP 中使用,小編相信有部分知識點可能是我們日常工作會見到或用到的。希望你能通過這篇文章學到更多知識。更多詳情敬請關注創(chuàng)新互聯行業(yè)資訊頻道。
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