Spring MVC过滤器-登录过滤的代码实现

一个非常简单的登录权限拦截器，具体代码如下：

以下代码是继承onceperrequestfilter实现登录过滤的代码：

/** 
 * 
 * @author geloin 
 * @date 2012-4-10 下午2:37:38 
 */ 
package com.test.spring.filter; 
 
import java.io.ioexception; 
import java.io.printwriter; 
 
import javax.servlet.filterchain; 
import javax.servlet.servletexception; 
import javax.servlet.http.httpservletrequest; 
import javax.servlet.http.httpservletresponse; 
 
import org.springframework.web.filter.onceperrequestfilter; 
 
/** 
 * 登录过滤 
 * 
 * @author geloin 
 * @date 2012-4-10 下午2:37:38 
 */ 
public class sessionfilter extends onceperrequestfilter { 
 
  /* 
   * (non-javadoc) 
   * 
   * @see 
   * org.springframework.web.filter.onceperrequestfilter#dofilterinternal( 
   * javax.servlet.http.httpservletrequest, 
   * javax.servlet.http.httpservletresponse, javax.servlet.filterchain) 
   */ 
  @override 
  protected void dofilterinternal(httpservletrequest request, 
      httpservletresponse response, filterchain filterchain) 
      throws servletexception, ioexception { 
 
    // 不过滤的uri 
    string[] notfilter = new string[] { "login.html", "index.html" }; 
 
    // 请求的uri 
    string uri = request.getrequesturi(); 
 
    // uri中包含background时才进行过滤 
    if (uri.indexof("background") != -1) { 
      // 是否过滤 
      boolean dofilter = true; 
      for (string s : notfilter) { 
        if (uri.indexof(s) != -1) { 
          // 如果uri中包含不过滤的uri，则不进行过滤 
          dofilter = false; 
          break; 
        } 
      } 
      if (dofilter) { 
        // 执行过滤 
        // 从session中获取登录者实体 
        object obj = request.getsession().getattribute("logineduser"); 
        if (null == obj) { 
          // 如果session中不存在登录者实体，则弹出框提示重新登录 
          // 设置request和response的字符集，防止乱码 
          request.setcharacterencoding("utf-8"); 
          response.setcharacterencoding("utf-8"); 
          printwriter out = response.getwriter(); 
          string loginpage = "...."; 
          stringbuilder builder = new stringbuilder(); 
          builder.append("<script type=\"text/javascript\">"); 
          builder.append("alert('网页过期，请重新登录！');"); 
          builder.append("window.top.location.href='"); 
          builder.append(loginpage); 
          builder.append("';"); 
          builder.append("</script>"); 
          out.print(builder.tostring()); 
        } else { 
          // 如果session中存在登录者实体，则继续 
          filterchain.dofilter(request, response); 
        } 
      } else { 
        // 如果不执行过滤，则继续 
        filterchain.dofilter(request, response); 
      } 
    } else { 
      // 如果uri中不包含background，则继续 
      filterchain.dofilter(request, response); 
    } 
  } 
 
} 

写完过滤器后，需要在web.xml中进行配置：

<filter> 
  <filter-name>sessionfilter</filter-name> 
  <filter-class>com.test.spring.filter.sessionfilter</filter-class> 
</filter> 
<filter-mapping> 
  <filter-name>sessionfilter</filter-name> 
  <url-pattern>/*</url-pattern> 
</filter-mapping> 

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。