详解Spring MVC拦截器实现session控制

未登录，不允许访问background文件夹内的页面，那如何判断是否登录呢？background是关键目录，每个操作该目录的人都需要写在日志表中，如何实现呢？拦截器是实现方案之一。

(1) 在com.geloin.spring.interceptor包中添加SystemInterceptor，并使其继承HandlerInterceptor

/**
 *
 * @author geloin
 */
package com.geloin.spring.interceptor; 

import java.io.PrintWriter;
import java.util.Iterator;
import java.util.Map; 

import javax.annotation.Resource;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse; 

import org.springframework.stereotype.Repository;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter; 

import com.embest.ruisystem.form.SystemLoggerForm;
import com.embest.ruisystem.form.SystemUserForm;
import com.embest.ruisystem.service.SystemLoggerService;
import com.embest.ruisystem.util.Constants;
import com.embest.ruisystem.util.DataUtil; 

/**
 *
 * @author geloin
 */
@Repository
public class SystemInterceptor extends HandlerInterceptorAdapter { 

  @Resource(name = "systemLoggerService")
  private SystemLoggerService systemLoggerService; 

  /*
   * (non-Javadoc)
   *
   * @see
   * org.springframework.web.servlet.handler.HandlerInterceptorAdapter#preHandle
   * (javax.servlet.http.HttpServletRequest,
   * javax.servlet.http.HttpServletResponse, java.lang.Object)
   */
  @SuppressWarnings({ "rawtypes", "unchecked" })
  @Override
  public boolean preHandle(HttpServletRequest request,
      HttpServletResponse response, Object handler) throws Exception { 

    request.setCharacterEncoding("UTF-8");
    response.setCharacterEncoding("UTF-8");
    response.setContentType("text/html;charset=UTF-8"); 

    // 后台session控制
    String[] noFilters = new String[] { "login.html", "veriCode.html",
        "index.html", "logout.html" };
    String uri = request.getRequestURI(); 

    if (uri.indexOf("background") != -1) {
      boolean beFilter = true;
      for (String s : noFilters) {
        if (uri.indexOf(s) != -1) {
          beFilter = false;
          break;
        }
      }
      if (beFilter) {
        Object obj = request.getSession().getAttribute(
            Constants.LOGINED);
        if (null == obj) { 

          // 未登录
          PrintWriter out = response.getWriter();
          StringBuilder builder = new StringBuilder();
          builder.append("<script type=\"text/javascript\" charset=\"UTF-8\">");
          builder.append("alert(\"页面过期，请重新登录\");");
          builder.append("window.top.location.href=\"");
          builder.append(Constants.basePath);
          builder.append("/background/index.html\";</script>");
          out.print(builder.toString());
          out.close();
          return false;
        } else {
          // 添加日志
          String operateContent = Constants.operateContent(uri);
          if (null != operateContent) {
            String url = uri.substring(uri.indexOf("background"));
            String ip = request.getRemoteAddr();
            Integer userId = ((SystemUserForm) obj).getId();
            SystemLoggerForm form = new SystemLoggerForm();
            form.setUserId(userId);
            form.setIp(ip);
            form.setOperateContent(operateContent);
            form.setUrl(url);
            this.systemLoggerService.edit(form);
          }
        }
      }
    } 

    Map paramsMap = request.getParameterMap(); 

    for (Iterator<Map.Entry> it = paramsMap.entrySet().iterator(); it
        .hasNext();) {
      Map.Entry entry = it.next();
      Object[] values = (Object[]) entry.getValue();
      for (Object obj : values) {
        if (!DataUtil.isValueSuccessed(obj)) {
          throw new RuntimeException("有非法字符：" + obj);
        }
      }
    } 

    return super.preHandle(request, response, handler);
  } 

}

(2) 修改context-dispatcher.xml，让spring管理拦截器

<mvc:interceptors>
  <bean class="com.geloin.spring.interceptor.SystemInterceptor" />
</mvc:interceptors> 

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