1. 启用aop
a. 在类上添加@aspect注解
b. 注入该类, 可以使用@component进行注入到spring容器中
2. 通过pointcut对象创建切入点
a. 在某个方法使用类似下面的方法进行注入
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@pointcut("execution(* com.sguess.service.iaopservice.*(..))") private void pointcut() { } |
i. 其中,execution表达式为
execution(modifiers-pattern? ret-type-pattern declaring-type-pattern? name-pattern(param-pattern)throws-pattern?)
ii. 注意, pointcut()方法名是后面切入的时候需要使用的
iii. 方法内可以什么也不写, 写了也调不到
iv. 也可以创建多个pointcut,例如再创建一个
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@pointcut("execution(* com.sguess.service.iaopservice.fun1(..))") private void pointcut2() { } |
这个的方法名就位pointcut2, 方法名不一样.
b. 创建after方法,before方法
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@after(value = "pointcut()") public void doafter() { system.out.println("do aop after function 01"); } |
i. after方法是指, 在配置了的切入点被执行后, 执行该方法.
ii. value中的pointcut() 是我们前面在创建@pointcut中的方法名. 也就是说,是通过方法名和切入点进行匹配的.
iii. 这个的方法名可以随便起.
iv. before方法同理
c. 带return的after方法,
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@afterreturning(returning = "str", pointcut = "pointcut()") public void doafterreturning(string str) throws exception { system.out.println("return value is: " + str); } |
i. afterreturn是指在被切入的方法执行后, 获取其返回值, 再执行该方法. 注意关键, 这个可以进行操作返回值.
ii. returning = "str",是指, 假设切入方法的返回的值变量名为str
doafterreturning(string str)方法的参数变量名必须和和returning保持一致, 这里也叫作str. 然后才能在方法体中使用.
iii. pointcut = "pointcut()"同样是指前面声明的pointcut方法名
3. 通过注解, 使用切入点
a. 监听方法参数
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@before("execution(public int com.sguess.service.*(int, int))") public void beformethod(joinpoint point) { string methodname = point.getsignature().getname(); list<object> args = arrays.aslist(point.getargs()); system.out.println("before functionname：" + methodname + ",parametername：" + args); } @after("execution(public int com.sguess.service.*(int, int))") public void aftermethod(joinpoint point) { string methodname = point.getsignature().getname(); list<object> args = arrays.aslist(point.getargs()); system.out.println("after functionname：" + methodname + ",parametername：" + args); } |
4. 执行顺序:
a.around的方法优先于before/after执行,after优先于afterreturn.
i. 代码
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@before("execution(public int com.sguess.service.*.*(int, int))") public void beformethod(joinpoint point) { system.out.println("before function"); } @after("execution(public int com.sguess.service.*.*(int, int))") public void aftermethod(joinpoint point) { system.out.println("after function"); } @afterreturning("execution(public int com.sguess.service.*.*(int, int))") public void afterreturnmethod(joinpoint point) { system.out.println("afterreturn function"); } @afterthrowing(value = "execution(public int com.sguess.service.*.*(int, int))", throwing = "e") public void afterreturningthrowing(joinpoint point, exception e) { system.out.println("afterreturnthrowing function"); } @around("execution(public int com.sguess.service.*.*(int, int))") public object aroundmethod(proceedingjoinpoint pdj) { system.out.println("start aroundfunction"); object result = null; try { system.out.println("around process start"); result = pdj.proceed(); system.out.println("around process end"); } catch (throwable e) { system.out.println("around process exception"); } system.out.println("after around process"); return result; } } |
执行结果:
start aroundfunction
around process start
before function
around process end
after around process
after function
afterreturn function
5.小结:
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@afterreturning(returning = "str", pointcut = "pointcut()")public void doafterreturning(string str) throws exception { system.out.println("return value is: " + str);}@before("execution(public int com.sguess.service.*.*(int, int))")public void beformethod(joinpoint point) { string methodname = point.getsignature().getname(); list<object> args = arrays.aslist(point.getargs()); system.out.println("before functionname：" + methodname + ",parametername：" + args);}@after("execution(public int com.sguess.service.*.*(int, int))")public void aftermethod(joinpoint point) { string methodname = point.getsignature().getname(); list<object> args = arrays.aslist(point.getargs()); system.out.println("after functionname：" + methodname + ",parametername：" + args);}@afterthrowing(value = "execution(public int com.sguess.service.*.*(int, int))", throwing = "e")public void afterreturningthrowing(joinpoint point, exception e) { string methodname = point.getsignature().getname(); list<object> args = arrays.aslist(point.getargs()); system.out.println("afterreturningthrowing functionname：" + methodname + ",parametername：" + args + ",exception：" + e);}@around("execution(public int com.sguess.service.*.*(int, int))")public object aroundmethod(proceedingjoinpoint pdj) { system.out.println("start aroundfunction"); object result = null; try { system.out.println("around process start"); result = pdj.proceed(); system.out.println("around process end"); } catch (throwable e) { system.out.println("around process exception"); } system.out.println("after around process"); return result;} |
总结
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原文链接：https://blog.csdn.net/sanpic/article/details/82800017
