Spring AOP 实现写事件日志功能

什么是AOP？AOP使用场景？AOP相关概念？Spring AOP组件？如何使用Spring AOP？等等这些问题请参考博文：Spring AOP 实现原理

下面重点介绍如何写事件日志功能，把日志保存到数据库中。 
事件日志是与主业务功能无关的逻辑，用AOP实现是再好不过了，其中因为有些数据库日志表中的字段参数需要传递，所以会用到自定义注解，将这些参数用自定义注解传递过来。

1.自定义注解Operation

package com.jykj.demo.filter;

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * @Descrption该注解描述方法的操作类型和方法的参数意义
 */
@Target(value = ElementType.METHOD)
@Retention(value = RetentionPolicy.RUNTIME)
@Documented
public @interface Operation {
    /**
     * @Description描述操作类型   为必填项,1:登录日志2：操作日志
     */
    int type();

    /**
     * @Description描述操作意义   比如申报通过或者不通过等
     */
    String desc() default ""; 

    /**
     * @Description描述操作方法的参数意义 数组长度需与参数长度一致,否则会参数与描述不一致的情况
     */
    String[] arguDesc() default {};
}

2.切面类EventLogAspect

package com.jykj.demo.filter;

import java.lang.reflect.Method;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.beans.factory.annotation.Autowired;

import com.jykj.demo.service.SysEventService;

//事件日志 切面,凡是带有 @Operation 注解的service方法都将会写日志
public class EventLogAspect {
    @Autowired
    SysEventService sysEventService;

    public void doAfterReturning(JoinPoint jp) {
        System.out.println(
                "log Ending method: " + jp.getTarget().getClass().getName() + "." + jp.getSignature().getName());
        Method proxyMethod = ((MethodSignature) jp.getSignature()).getMethod();
        Method soruceMethod;
        try {

            soruceMethod = jp.getTarget().getClass().getMethod(proxyMethod.getName(), proxyMethod.getParameterTypes());
            Operation oper = soruceMethod.getAnnotation(Operation.class);

            if (oper != null) {
                System.out.println(oper.desc());
                // 解析参数
                sysEventService.insertEventLog(oper.type(),oper.desc()+"("+extractParam(jp.getArgs(),oper.arguDesc())+") 成功");
            }

        } catch (NoSuchMethodException e) {
            e.printStackTrace();
        } catch (SecurityException e) {
            e.printStackTrace();
        }catch (Exception e) {
            e.printStackTrace();
        }
    }
    public void doAfterThrowing(JoinPoint jp, Throwable ex) {
        Method proxyMethod = ((MethodSignature) jp.getSignature()).getMethod();
        Method soruceMethod;
        try {
            soruceMethod = jp.getTarget().getClass().getMethod(proxyMethod.getName(), proxyMethod.getParameterTypes());
            Operation oper = soruceMethod.getAnnotation(Operation.class);
            if (oper != null) {
                System.out.println(oper.desc());
                sysEventService.insertEventLog(oper.type(),oper.desc()+
                        "("+extractParam(jp.getArgs(),oper.arguDesc())+" 出现异常："+ex.getMessage());
            }
        } catch (NoSuchMethodException e) {
            e.printStackTrace();
        } catch (SecurityException e) {
            e.printStackTrace();
        }
    }
    private String extractParam(Object[] objParam, String[] arguDesc) {
        StringBuilder sb = new StringBuilder();
        int len = objParam.length<arguDesc.length?objParam.length:arguDesc.length;//取最小值
        for (int i = 0; i < len; i++) {
            //空字符串将不解析
            if(arguDesc[i]!=null && !arguDesc[i].isEmpty()){
                sb.append(arguDesc[i]+":"+objParam[i]+",");
            }
        }
        String rs = sb.toString(); 
        return rs.substring(0,rs.length()-1);
    }
}

3.切入点 主业务逻辑类FrmAppsService

package com.jykj.demo.service;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import com.jykj.demo.dao.FrmAppsMapper;
import com.jykj.demo.entity.FrmApps;
import com.jykj.demo.filter.Operation;
import com.jykj.demo.mapper.AbstractService;

@Service
public class FrmAppsService {
    @Autowired
    FrmAppsMapper mapper;

    @Operation(type=1,desc="更新框架应用",arguDesc={"","操作类型"})
    public int access(FrmApps app,String action){
        return mapper.access(app,action);
    }
}

4.Spring xml对AOP的配置

<bean id="aspectEventLog" class="com.jykj.demo.filter.EventLogAspect" />
    <!-- <aop:aspectj-autoproxy />  -->
    <!--配置service包下所有类或接口的所有方法--> 
    <aop:config proxy-target-class="true">  
        <aop:aspect id="EventLogAspect" ref="aspectEventLog">  
            <aop:pointcut id="myService"  
                expression="execution(* com.jykj.demo.service.*.*(..)) " />  
            <aop:after-returning pointcut-ref="myService" method="doAfterReturning"/>  
            <aop:after-throwing pointcut-ref="myService" method="doAfterThrowing" throwing="ex"/>
        </aop:aspect>  
    </aop:config>
    <!-- 控制器 -->
    <context:component-scan base-package="com.jykj.demo.controller" />
    <!-- service -->
    <context:component-scan base-package="com.jykj.demo.service" />
    <context:component-scan base-package="com.jykj.demo.filter" />

需要注意的是 proxy-target-class=”true” ，如果没有这个，目标类若是实现了接口，将会以JDK代理的方式，否则采用的是CGLib代理的方式，如果启动项目报错了，会报代理类无法转换的问题，这时候把这个配置写上就可以了。

这样就实现了写日志的功能，只要在需要写日志的service类的方法上用自定义注解Operation注解即可

5.输出 （编辑一个记录时）

log Ending method: com.jykj.demo.service.FrmAppsService.access
更新框架应用
log Ending method: com.jykj.demo.service.SysEventService.insertEventLog

另外再附加 在未登录时禁止访问页面的功能 采用拦截器 
SecurityInterceptor类

package com.jykj.demo.filter;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import com.jykj.demo.util.Helper;

public class SecurityInterceptor implements HandlerInterceptor{

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
            throws Exception {
        HttpSession session = request.getSession();
        if (session.getAttribute(Helper.SESSION_USER) == null) {
            throw new AuthorizationException();
        } else {
            return true;
        }
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
            ModelAndView modelAndView) throws Exception {
        // TODO Auto-generated method stub

    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
            throws Exception {
        // TODO Auto-generated method stub

    }

}

对应的拦截器的配置 spring-mvc.xml

<mvc:interceptors>
        <mvc:interceptor>
            <mvc:mapping path="/*"/>
            <mvc:exclude-mapping path="/login"/>
            <mvc:exclude-mapping path="/signIn"/>
            <mvc:exclude-mapping path="/register"/>
            <bean class="com.jykj.demo.filter.SecurityInterceptor">
            </bean>
        </mvc:interceptor>
    </mvc:interceptors>
    <!-- bean 处理未登录重定向到登录界面 -->
    <bean id="handlerExceptionResolver"
        class="org.springframework.web.servlet.handler.SimpleMappingExceptionResolver">
        <property name="exceptionMappings">
            <props>
                <prop key="com.jykj.demo.filter.AuthorizationException">redirect:login</prop>
            </props>
        </property>
    </bean>

异常类AuthorizationException

package com.jykj.demo.filter;

public class AuthorizationException extends Exception{

    private static final long serialVersionUID = 1L;

}