前台提交表单，后台接收问题。且前后台是两个分开的项目。。它们之间是怎么传递参数的啊。。。求高手解答

具体是一个JSP页面把表单内容提交给了一个Servlet类来处理，处理完之后再转向一个Servlet做处理，第二个Servlet，dopost方法里面有如下代码：
DepartmentInfoService orgServices = new DepartmentInfoServiceImpl().getDepartmentinfo();
if(request.getParameter("dname")!=null){
if(request.getParameter("dname").length()==0){
DepartmentInfos dif = orgServices.getAllDepartmentInfo();
request.setAttribute("oas", dif.getDepartmentinfos());
}else{
if(request.getParameter("query")!=null){
if(request.getParameter("query").equals("single")){
DepartmentInfo oas = orgServices.getDepartmentInfoByName(request.getParameter("dname"));
//未查询出结果返回NULL的话会报错，这里new出一个空的对象，判断id是否为空
if(oas.getId()!=null){
List l = new ArrayList();
l.add(oas);
request.setAttribute("oas", l);
}
}else if(request.getParameter("query").equals("mult")){
String[] dname=request.getParameter("dname").split(",");
DepartmentInfos departmentInfos = new DepartmentInfos();
departmentInfos.setDnames(dname);
DepartmentInfos dif  = orgServices.getDepartmentInfoByNames(departmentInfos);
request.setAttribute("oas", dif.getDepartmentinfos());
}

}else{
DepartmentInfo oas = orgServices.getDepartmentInfoByName(request.getParameter("dname"));
if(oas.getId()!=null){
List l = new ArrayList();
l.add(oas);
request.setAttribute("oas", l);
}
}

request.setAttribute("dname", request.getParameter("dname"));
request.setAttribute("query", request.getParameter("query"));
}
}else{
DepartmentInfos dif = orgServices.getAllDepartmentInfo();
request.setAttribute("oas", dif.getDepartmentinfos());
}

RequestDispatcher dis= request.getRequestDispatcher("/pages/index.jsp");
dis.forward(request, response);
}
这个有点不懂了。。本人菜鸟刚学，求指点