select框如何回显数据

前端jsp代码

<form action="ListPlatformServlet" method="post" id="searchForm">
		平台类型：<select name="platformType">
								<option value="">--请选择--</option>
								<c:forEach var="p" items="${platforms }"> 
									<option value="${p.platformType }" 
										<c:if test="${p.platformType  eq platformType}">selected</c:if>>${p.platformType }
									</option>
								</c:forEach>
					</select>
		&emsp;&emsp;&emsp;&emsp;
		<input type="submit" value="查询" />&emsp;&emsp;
</form>

<c:if test="${p.platformType eq platformType}">selected</c:if>
判断如果回显值等于遍历集合中的值时，test=true，那么就执行<c:if></c:if>中的语句，那么就实现了选择框的回显。

后台servlet

@WebServlet("/ListPlatformServlet")
public class ListPlatformServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;

	protected void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		String platformName = request.getParameter("platformName");
		//获取前台的值
		String platformType = request.getParameter("platformType");
		String pageIndex = request.getParameter("pageIndex");
		Page page = new Page();
		PlatformService ps = new PlatformService();
		List<Platform> platforms = ps.listPlatform(page, pageIndex, platformName, platformType);
		request.setAttribute("platformName", platformName);
		//条件查询的回显值
		request.setAttribute("platformType", platformType);
		request.setAttribute("page", page);
		request.setAttribute("platforms", platforms);
		request.getRequestDispatcher("listPlatform.jsp").forward(request, response);
	}
	protected void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		doGet(request, response);
	}
}