package testGridTree.action;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import testGridTree.GridTreeDao;
import testGridTree.GridTreeUtil;
/**
* 演示懒加载表格树:第一次显示执行的action,也就是initLazy.
* 用途是:只查询出来应该显示的第一层的节点.
* connect me:419723443@qq.com
*/
public class InitTableTreeLazyAction extends Action {
// 每页行数
private static int DEFAULT_PAGE_SIZE = 10;
/**
* 获取类型的下拉菜单数据
* @param mapping
* @param form
* @param request
* @param response
* @return
*/
public ActionForward execute(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response) {
GridTreeDao dao = new GridTreeDao();
List list = new ArrayList();
// 结果行数
int totalNum = 0;
int[] rowStartEnd;
int len = 0;
try {
totalNum = dao.getFirstLevelCount();
/** 下面的三步都是使用的自己的类,用来设置一些在json要使用一些分页信息 */
// 调用工具类的方法计算起始行和终止行（为前开和后开的）。
rowStartEnd = GridTreeUtil.getStartAndEndInfo(request, totalNum,
DEFAULT_PAGE_SIZE);
list = dao.getList(rowStartEnd[0], rowStartEnd[1]);
// 调用工具类的方法得到json字符串。
String jsonStr = GridTreeUtil.getJsonStr(list, request);
response.setContentType("text/html; charset=UTF-8");
System.out.println("json串:" + jsonStr);
PrintWriter out = response.getWriter();
out.println(jsonStr);
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
}