无限级树（Java递归） 2007-02-08 10:26 这几天，用java写了一个无限极的树，递

文件名称: 无限级树（Java递归）

所属分类: Java

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文件大小: 7kb

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上传时间: 2008-11-12

提供者: taij****

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详细说明：无限级树（Java递归） 2007-02-08 10:26 这几天，用java写了一个无限极的树，递归写的，可能代码不够简洁，性能不够好，不过也算是练习，这几天再不断改进。前面几个小图标的判断，搞死我了。 package com.nickol.servlet; import java.io.IOException; import java.io.PrintWriter; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.util.ArrayList; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import com.nickol.utility.DB; public class category extends HttpServlet { /** * The doGet method of the servlet.
* * This method is called when a form has its tag value method equals to get. * * @param request the request send by the client to the server * @param response the response send by the server to the client * @throws ServletException if an error occurred * @throws IOException if an error occurred */ public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setCharacterEncoding("utf-8"); response.setContentType("text/html"); PrintWriter out = response.getWriter(); out .println(""); out.println(""); out.println(" Category" + "" + "" + ""); out.println(" "); out.println(showCategory(0,0,new ArrayList(),"0")); out.println(" "); out.println(""); out.flush(); out.close(); } public String showCategory(int i,int n,ArrayList frontIcon,String countCurrent){ int countChild = 0; n++; String webContent = new String(); ArrayList temp = new ArrayList(); try{ Connection conn = DB.GetConn(); PreparedStatement ps = DB.GetPs("select * from category where pid = ?", conn); ps.setInt(1, i); ResultSet rs = DB.GetRs(ps); if(n==1){ if(rs.next()){ webContent += "";//插入结尾的减号 temp.add(new Integer(0)); } webContent += " ";//插入站点图标 webContent += rs.getString("cname"); webContent += "
\n"; webContent += showCategory(Integer.parseInt(rs.getString("cid")),n,temp,"0"); } if(n==2){ webContent += "

\n"; }else{ webContent += "
\n"; } while(rs.next()){ for(int k=0;k";//插入结尾的减号 temp = (ArrayList)frontIcon.clone(); temp.add(new Integer(0)); }else{ webContent += "";//插入结尾的直角 } }else{ if(checkChild(Integer.parseInt(rs.getString("cid")))){ webContent += "";//插入未结尾的减号 temp = (ArrayList)frontIcon.clone(); temp.add(new Integer(1)); }else{ webContent += "";//插入三叉线 } } if(checkChild(Integer.parseInt(rs.getString("cid")))){ webContent += " ";//插入文件夹图标 }else{ webContent += " ";//插入文件图标 } webContent += rs.getString("cname"); webContent += "
\n"; webContent += showCategory(Integer.parseInt(rs.getString("cid")),n,temp,countCurrent+countChild); countChild++; } webContent += "
\n"; DB.CloseRs(rs); DB.ClosePs(ps); DB.CloseConn(conn); }catch(Exception e){ e.printStackTrace(); } return webContent; } public boolean checkChild(int i){ boolean child = false; try{ Connection conn = DB.GetConn(); PreparedStatement ps = DB.GetPs("select * from category where pid = ?", conn); ps.setInt(1, i); ResultSet rs = DB.GetRs(ps); if(rs.next()){ child = true; } DB.CloseRs(rs); DB.ClosePs(ps); DB.CloseConn(conn); }catch(Exception e){ e.printStackTrace(); } return child; } } --------------------------------------------------------------------- tree.js文件 function changeState(countCurrent,countChild){ var object = document.getElementById("level" + countCurrent + countChild); if(object.style.display=='none'){ object.style.display='block'; }else{ object.style.display='none'; } var cursor = document.getElementById("cursor" + countCurrent + countChild); if(cursor.src.indexOf("images/tree_minus.gif")>=0) {cursor.src="images/tree_plus.gif";} else if(cursor.src.indexOf("images/tree_minusbottom.gif")>=0) {cursor.src="images/tree_plusbottom.gif";} else if(cursor.src.indexOf("images/tree_plus.gif")>=0) {cursor.src="images/tree_minus.gif";} else {cursor.src="images/tree_minusbottom.gif";} var folder = document.getElementById("folder" + countCurrent + countChild); if(folder.src.indexOf("images/icon_folder_channel_normal.gif")>=0){ folder.src = "images/icon_folder_channel_open.gif"; }else{ folder.src = "images/icon_folder_channel_normal.gif"; } ...展开收缩