tree.java

JSP javaBean 数据库无限级动态树状菜单

package com.netmarch.folder;

import java.sql.ResultSet;
import java.sql.SQLException;

public class Tree {

	Cn conn = new Cn();

	//注意这里的文件中心对应的ID号为491，如果您对应的不是这个ID，请您自己修改一下ID号
	public void init(javax.servlet.jsp.JspWriter out,
			javax.servlet.http.HttpServletRequest request) throws Exception {
		out.println("<title>文件中心</title>");
		dowith(request);
		buildTree(out, 491, 0, "0");// 初始调用
	}

	//下面代码为测试类。
	private void dowith(javax.servlet.http.HttpServletRequest request)
			throws SQLException {
		if (request.getParameter("parentid") == null
				|| request.getParameter("parentid").equals(""))
			return;
		String action = request.getParameter("action");
		if (action.equals("add"))
			conn.executeUpdate("insert into item(parentid,name) values('"
					+ request.getParameter("parentid") + "','"
					+ request.getParameter("name") + "')");
		else if (action.equals("delete"))
			conn.executeUpdate("delete from item where id="
					+ request.getParameter("parentid") + " or parentid="
					+ request.getParameter("parentid"));
	}

	public void buildTree(javax.servlet.jsp.JspWriter out, int parentid,
			int level, String pids) throws Exception {
		level++;
		ResultSet rs = conn
				.executeQuery("select * from item where sn like '491,%' and webid=97 and isAuditing=1  and parentid="
						+ parentid + "  order by id");
		String pic="";
		///ResultSet rs = conn.executeQuery("select a.id,a.parentid,b.id,b.parentid,a.name,b.name from item a ,item b where ( a.id =b.parentid ) and a.id =491 ");
		while (rs.next()) {
			out.println("<div>");
			for (int i = 0; i < level - 1; i++)
				out.print("<img src=\"img/T.gif\"> ");

			//if (has_child(rs.getInt("id"))) {
			if(level==1){
				pic="plus.gif";
			}else{
				
				pic="arrow.gif";
			}
				out
						.print("<img alt=\"展开\" style=\"cursor:hand;\" onclick=\"myClick('"
								+ rs.getInt("id")
								+ "');\" id=\"img"
								+ rs.getInt("id")
								+ "\" src=\"img/"+pic+"\">");
				out.print("<span onclick=\"myClick1('" + rs.getInt("id")
						+ "');\" style=\"cursor:default;\" id=\"span"
						+ rs.getInt("id") + "\">" + rs.getString("name")
						+ "</span>");
				out.println("<div style=\"display:none;\" id=\"div"
						+ rs.getInt("id") + "\" pa='" + pids + ","
						+ rs.getInt("id") + "'>");
				buildTree(out, rs.getInt("id"), level, pids + ","
						+ rs.getInt("id"));//递归调用
				out.println("</div>");
			//} else
//				out
//						.print("<img src=\"img/minus.gif\">  <span onclick=\"myClick1('"
//								+ rs.getInt("id")
//								+ "');\" style=\"cursor:default;\" id=\"span"
//								+ rs.getInt("id")
//								+ "\">"
//								+ rs.getString("name")
//							 + "</span>");
			out.println("</div>");
		}
		rs.close();
		rs = null;
	}

	private boolean has_child(int parentid) throws Exception {
		ResultSet rs = conn
				.executeQuery("select * from item where sn like '491,%' and webid=97 and isAuditing=1  and parentid="
						+ parentid + "  order by id");
		return rs.next();
	}
	//注意。这里的like '491,%'是妈出最大的级数，呵呵，并且你要在你的表里面建一个SN，例子如下：491，表示为第一级以此类推

	//下面这个是测试用
	public String getOption() throws Exception {
		String option = "";
		ResultSet rs = conn.executeQuery("select id from item order by id");
		while (rs.next())
			option += "<option value=\"" + rs.getInt("id") + "\">"
					+ rs.getInt("id") + "</option>\n";
		return option;
	}

}