spring boot 配置Filter过滤器的方法

filter 过滤器是web开发中很重要的一个组件，下面以一个session登陆的例子介绍下spring boot中如何使用filter

首先要准备一个实现了filter的接口的类 sessionfilter：

import org.slf4j.loggerfactory;

import javax.servlet.*;
import javax.servlet.http.httpservletrequest;
import javax.servlet.http.httpservletresponse;
import javax.servlet.http.httpsession;
import java.io.ioexception;
import java.util.arraylist;
import java.util.list;
import java.util.regex.matcher;
import java.util.regex.pattern;

/**
 * created by mazhenhua on 2016/12/27.
 *
 * 过滤器
 */
public class sessionfilter implements filter {
  private static final org.slf4j.logger logger = loggerfactory.getlogger(sessionfilter.class);


  /**
   * 封装，不需要过滤的list列表
   */
  protected static list<pattern> patterns = new arraylist<pattern>();

  @override
  public void init(filterconfig filterconfig) throws servletexception {

  }

  @override
  public void dofilter(servletrequest servletrequest, servletresponse servletresponse, filterchain chain) throws ioexception, servletexception {
    httpservletrequest httprequest = (httpservletrequest) servletrequest;
    httpservletresponse httpresponse = (httpservletresponse) servletresponse;
    logger.info("aaaaaaaaaa");
    string url = httprequest.getrequesturi().substring(httprequest.getcontextpath().length());
    if (url.startswith("/") && url.length() > 1) {
      url = url.substring(1);
    }

    if (isinclude(url)){
      chain.dofilter(httprequest, httpresponse);
      return;
    } else {
      httpsession session = httprequest.getsession();
      if (session.getattribute("") != null){
        // session存在
        chain.dofilter(httprequest, httpresponse);
        return;
      } else {
        // session不存在 准备跳转失败
        /* requestdispatcher dispatcher = request.getrequestdispatcher(path);
          dispatcher.forward(request, response);*/
        chain.dofilter(httprequest, httpresponse);
        return;
      }
    }


  }

  @override
  public void destroy() {

  }


  /**
   * 是否需要过滤
   * @param url
   * @return
   */
  private boolean isinclude(string url) {
    for (pattern pattern : patterns) {
      matcher matcher = pattern.matcher(url);
      if (matcher.matches()) {
        return true;
      }
    }
    return false;
  }

}

实际开发中往往有很多请求要直接请求进来，不需要鉴权登陆的，所以代码中过滤掉这种请求的代码，装进list就好了。

  /**
   * 配置过滤器
   * @return
   */
  @bean
  public filterregistrationbean somefilterregistration() {
    filterregistrationbean registration = new filterregistrationbean();
    registration.setfilter(sessionfilter());
    registration.addurlpatterns("/*");
    registration.addinitparameter("paramname", "paramvalue");
    registration.setname("sessionfilter");
    return registration;
  }

  /**
   * 创建一个bean
   * @return
   */
  @bean(name = "sessionfilter")
  public filter sessionfilter() {
    return new sessionfilter();
  }

经过上面这俩步的配置，过滤器基本上就可以了。

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。