0070 过滤器调用Spring的bean操作数据库

假设有这样的需求：将用户每次请求的ip、时间、请求、user-agent存入数据库，很明显可以用过滤器实现，在过滤器中获取到这些数据调用mybatis的mapper存入数据库，但问题来了：mybatis的映射接口规则自动生成的Dao实现类存在于Spring容器中，在filter中如何才能注入或者调用呢？

首先是web.xml配置

	<filter>
		<!-- 注意下面这个过滤器名称要跟下面的spring-context.xml的相同 -->
        <filter-name>myRequestLogFilter</filter-name> 
        <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
        <init-param>
            <param-name>targetFilterLifecycle</param-name>
            <param-value>true</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>myRequestLogFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

写filter

package net.sonngdemo.wms.util;


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

import javax.servlet.*;
import java.io.IOException;

/**
 * Created by Administrator on 2017/7/3.
 */

public class ReqeustFilter implements Filter {

    @Autowired
    private RequestFilterInSpring requestFilterInSpring; /*注入下面的Spring容器中的bean，实现了具体的过滤器方法*/

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        requestFilterInSpring.filter(request,response);  //具体的过滤规则写在下面一个类中
        chain.doFilter(request,response);
    }

    @Override
    public void destroy() {

    }
}

配置Spring-context.xml

<bean name="myRequestLogFilter" class="net.sonngdemo.wms.util.ReqeustFilter" ></bean> 
<!-- 注意这个bean的name要跟上面的web.xml中的名称相同 -->

写一个Spring Bean，具体实现过滤器方法

package net.sonngdemo.wms.util;

import net.sonngdemo.wms.dao.RequestLogMapper;
import net.sonngdemo.wms.domain.RequestLog;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import java.util.Date;

/**
 * Created by Administrator on 2017/7/3.
 */
@Component("requestFilterInSpring")  /*注意名称跟上面过滤器中注入的名称相同*/
public class RequestFilterInSpring {
    @Autowired
    private RequestLogMapper requestLogMapper; /*注入mapper实现类*/

    public void filter(ServletRequest request,ServletResponse response){ /*具体实现过滤器方法*/
        HttpServletRequest httpRequest=(HttpServletRequest)request;
        String uri=httpRequest.getRequestURI();
        String regex = "/wms/(css|errorPage|fonts|js|media)/.*";
        if (!uri.matches(regex)) {
            RequestLog requestLog=new RequestLog();
            requestLog.setIp(request.getRemoteHost());
            requestLog.setDate(new Date());
            requestLog.setRequest(uri);
            requestLog.setUserAgent(httpRequest.getHeader("user-agent"));
            requestLogMapper.insertLog(requestLog);
        }
    }
}

其他mapper略

总结：

1. web.xml中配置一个过滤器代理
2. 写一个过滤器实现Filter接口，通过调用Spring容器中的bean来实现过滤方法
3. 在Spring配置文件中，创建该过滤器的bean对象，注意该该bean的名称要跟web.xml中的名称相同
4. 写一个bean，具体实现过滤方法，用@component注解