如何创建一个与Servlet-api完全解耦和的管理员后台操作日志监控

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在日常开发系统后台时，需要针对管理员操作进行监控，如果使用Spring这一套技术体系，使用AOP切面编程+自定义注解不妨是一个好办法，但是在使用这一套体系的同时也会出现一些坑。比如这一套体系是完全依赖于WEB环境，脱离WEB环境就会出现出现ServletRequestAttributes为null的情况。那么如何解决这个问题。

首先快速搭建一个Spring 的运行环境具体jar参照下图：

<dependency> <groupId>javax.servlet</groupId> <artifactId>servlet-api</artifactId> <version>2.5</version> <scope>provided</scope> </dependency> <!--jstl--> <dependency> <groupId>javax.servlet</groupId> <artifactId>jstl</artifactId> <version>1.2</version> </dependency> <!--spring--> <!--spring相关依赖--> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-core</artifactId> <version>4.3.2.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> <version>4.3.2.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context-support</artifactId> <version>4.3.2.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-beans</artifactId> <version>4.3.2.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-aop</artifactId> <version>4.3.2.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-expression</artifactId> <version>4.3.2.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-aspects</artifactId> <version>4.3.2.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-tx</artifactId> <version>4.3.2.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-web</artifactId> <version>4.3.2.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-jdbc</artifactId> <version>4.3.2.RELEASE</version> </dependency> <!--springmvc--> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-webmvc</artifactId> <version>4.3.2.RELEASE</version> </dependency> <!--mybatis--> <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis</artifactId> <version>3.2.5</version> </dependency> <!--mybatis-spring--> <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis-spring</artifactId> <version>1.3.2</version> </dependency> <!--mysql--> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.38</version> </dependency> <!--druid--> <dependency> <groupId>com.alibaba</groupId> <artifactId>druid</artifactId> <version>1.1.10</version> </dependency> <dependency> <groupId>com.alibaba</groupId> <artifactId>fastjson</artifactId> <version>1.2.47</version> </dependency> <!--commons-fileupload--> <dependency> <groupId>commons-fileupload</groupId> <artifactId>commons-fileupload</artifactId> <version>1.3</version> </dependency> <!--jackson--> <dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-databind</artifactId> <version>2.9.5</version> </dependency> <!--log4j--> <dependency> <groupId>log4j</groupId> <artifactId>log4j</artifactId> <version>1.2.16</version> </dependency> <!--junit测试--> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.12</version> <scope>test</scope> </dependency>

首先对前面的开发步骤做一个简单的讲解，首先开发一个自定义注解：

import java.lang.annotation.ElementType; import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; import java.lang.annotation.Target; //在方法上使用 @Target({ElementType.METHOD}) //类一旦运行 起作用 @Retention(RetentionPolicy.RUNTIME) public @interface LogAnnotation { public String value(); }

开发环绕通知（常规做法，下面做修改）

import org.aopalliance.intercept.MethodInterceptor; import org.aopalliance.intercept.MethodInvocation; import org.springframework.web.context.request.RequestContextHolder; import org.springframework.web.context.request.ServletRequestAttributes; import javax.servlet.http.HttpSession; import java.lang.reflect.Method; import java.util.Date; /* * * 这是一个环绕通知 * 需要实现 * */ public class Around implements MethodInterceptor { @Override public Object invoke(MethodInvocation mi) throws Throwable { /* * 1.什么人-------- * 2.什么时间 new Date() * 3.什么事情----方法名 * 4.是否成功-----能 * */ ServletRequestAttributes s = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes(); //获取HttpRequst对象，于Servlet强耦合 HttpSession session = s.getRequest().getSession(); //拿到存放在Session的数据 String adminName = (String)session.getAttribute("admin"); //时间 Date date = new Date(); //什么事情 Method method = mi.getMethod(); //拿到类对象 反射 LogAnnotation annotation = method.getAnnotation(LogAnnotation.class); //通过反射拿到的实例 调用方法 String name = annotation.value(); //是否成功 boolean flag = false; Object proceed = null; try { proceed = mi.proceed(); flag=true; }catch (Exception a){ a.printStackTrace(); } //这里不做插入数据库的操作 System.out.println(adminName+"管理员在"+date+"执行了"+name+"成功了么？"+flag); return proceed; } }

上述实现的修改（于Servlet弱耦合），利用Spring的DI特性，实现对操作对象的自动注入。 import org.aopalliance.intercept.MethodInterceptor; import org.aopalliance.intercept.MethodInvocation; import java.lang.reflect.Method; import java.util.Date; /* * 这是一个环绕通知 * 需要实现 * */ public class Around implements MethodInterceptor { //将操作对象声明为成员变量 private String adminName; //设置公开访问方法，实现未来的数据注入 public void setAdminName(String adminName) { this.adminName = adminName; } @Override public Object invoke(MethodInvocation mi) throws Throwable { Date date = new Date(); //什么事情 Method method = mi.getMethod(); //拿到类对象 反射 LogAnnotation annotation = method.getAnnotation(LogAnnotation.class); //通过反射拿到的实例 调用方法 String name = annotation.value(); //是否成功 boolean flag = false; Object proceed = null; try { proceed = mi.proceed(); flag=true; }catch (Exception a){ a.printStackTrace(); } System.out.println(adminName+"管理员在"+date+"执行了"+name+"成功了么？"+flag); return proceed; } }

以上将操作数据设定为成员变量，未来我可以在controller层和业务层增加一个过滤器，实现对操作数据的注入。

3. 对通知类使用Spring进行管理

<!--配置组装切面--> <aop:config proxy-target-class="true"> <!--配置切入点--> <aop:pointcut id="pc" expression="@annotation(com.baizhi.aop.LogAnnotation)"/> <!--组装切面--> <aop:advisor advice-ref="around" pointcut-ref="pc"/> </aop:config>

过滤器的开发

import com.baizhi.aop.Around; import org.springframework.web.context.WebApplicationContext; import org.springframework.web.context.support.WebApplicationContextUtils; import javax.servlet.*; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpSession; import java.io.IOException; public class LogFilter implements Filter { @Override public void init(FilterConfig filterConfig) throws ServletException { } @Override public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException { filterChain.doFilter(servletRequest, servletResponse); HttpServletRequest res = (HttpServletRequest)servletRequest; HttpSession session = res.getSession(); String admin = (String) session.getAttribute("admin"); ServletContext servletContext = session.getServletContext(); //使用这个web工具类拿到WebApplicationContext对象 WebApplicationContext webApplicationContext = WebApplicationContextUtils.getWebApplicationContext(servletContext); //能通过WebApplicationContext类拿到已经初始化的Bean Around around = (Around) webApplicationContext.getBean("around"); //通过set方法注入数据 around.setAdminName(admin); } @Override public void destroy() { } }

5.最后在web.xml中进行配置

<!--配置过滤器位置--> <filter> <filter-name>log</filter-name> <filter-class>com.baizhi.filter.LogFilter</filter-class> </filter> <!--过滤器拦截位置--> <filter-mapping> <filter-name>log</filter-name> <url-pattern>/*</url-pattern> </filter-mapping>

搞定测试，这样做的好处是可以在测试某个模块时，只关注于String类型的name就行了，不必去考虑web的session的获取问题和null值问题