DTree生成漂亮的动态树型菜单

DTree生成漂亮的动态树型菜单
dtree是一个免费的javascript脚本，只需定义有限的几个参数，就可以做出漂亮的树型菜单。
以下是dtree的用法示例：
1）初始化菜单

 

<script type="text/javascript">
   <!--
   var Tree = new Array;
   // nodeId | parentNodeId | nodeName | nodeUrl
   Tree[0]   = "1|0|Page 1|#";
   Tree[1]   = "2|1|Page 1.1|#";
   Tree[2]   = "3|1|Page 1.2|#";
   Tree[3]   = "4|3|Page 1.2.1|#";
   Tree[4]   = "5|1|Page 1.3|#";
   Tree[5]   = "6|2|Page 1.1.1|#";
   Tree[6]   = "7|6|Page 1.1.1.1|#";
   Tree[7]   = "8|6|Page 1.1.1.2|#";
   Tree[8]   = "9|1|Page 1.4|#";
   Tree[9]   = "10|9|Page 1.4.1|#";
   Tree[10] = "11|0|Page 2|#";
   //-->
</script>

 

2）调用函数

<div class="tree">
   <script type="text/javascript">
   <!--
    createTree(Tree,1,7);   // starts the tree at the top and open it at node nr. 7
   //-->
   </script>
</div>

2.jsp动态实现
    分以下步骤实现动态的树型菜单：
    1）在数据库建tree_info表，有nodeId，parentNodeId，nodeName，nodeUrl四个字段，来存储节点信息。
    2）编写java类，用于从数据库找出节点信息，并且生成javascript脚本。
    3）编写tag类。用于封装逻辑，简化jsp的开发。
    4）建一个web程序进行测试。
3.详细过程
    1）在数据库建表，脚本如下：

    CREATE TABLE `test`.`tree_info` (
    `node_id` INTEGER UNSIGNED NOT NULL DEFAULT -1,
    `parent_id` INTEGER UNSIGNED NOT NULL DEFAULT -1,
    `node_name` VARCHAR(45) NOT NULL,
    `ref_url` VARCHAR(45) NOT NULL,
    PRIMARY KEY(`node_id`)
)

我使用mysql数据库，如果脚本细节有出入，请自行修改
     按照上面的dTree示例插入数据
    2）编写TreeInfo.java，这个类用于封装节点信息
 

  package com.diegoyun.web.tree;
/**
 * @author Diegoyun
 * @version 1.0
 */
public class TreeInfo {
 private int nodeId = -1;//node id
 private int parentId = -1;//parentId
 private String nodeName = null;//node name
 private String url = null;//url references
 public int getNodeId() {
  return nodeId;
 }
 public void setNodeId(int nodeId) {
  this.nodeId = nodeId;
 }
 public int getParentId() {
  return parentId;
 }
 public void setParentId(int parentId) {
  this.parentId = parentId;
 }
 public String getNodeName() {
  return nodeName;
 }
 public void setNodeName(String nodeName) {
  this.nodeName = nodeName;
 }
 public String getUrl() {
  return url;
 }
 public void setUrl(String url) {
  this.url = url;
 }
}

    编写TreeUtil.java，用于从数据库得到节点信息，封装到TreeInfo对象，并生成javascript脚本
   

TreeUtil.java
    package com.diegoyun.web.tree;
   import java.util.Collection;
   import java.util.ArrayList;
   import java.util.Iterator;
   import java.util.List;
   import java.sql.PreparedStatement;
   import java.sql.ResultSet;
   import java.sql.Connection;
   import java.sql.DriverManager;
   /**
    * @author Diegoyun
    * @version 1.0
    */
   public class TreeUtil {
    public static List retrieveNodeInfos(){
     List coll = new ArrayList();
     String driverName = "com.mysql.jdbc.Driver";
     String host = "localhost";
     String port = ":3306";
     String serverID = "test";
     String userName = "root";
     String userPwd = "root";
     String url = "jdbc:mysql://" + host + port + "/" + serverID ;
     Connection conn = null ;
     PreparedStatement ps = null;
     ResultSet rs = null;
     try{
      Class.forName(driverName).newInstance();
      conn = DriverManager.getConnection(url , userName , userPwd);
      String sql = "select * from tree_info";
      ps = conn.prepareStatement(sql);
      rs = ps.executeQuery();
      TreeInfo info = null;
      while(rs!=null && rs.next()){
       info = new TreeInfo();
       info.setNodeId(rs.getInt(1));
       info.setParentId(rs.getInt(2));
       info.setNodeName(rs.getString(3));
       info.setUrl(rs.getString(4));
       coll.add(info);
      }
   //             if(rs!=null){
   //                 rs.close();
   //                 rs=null;
   //             }
   //             if(ps!=null){
   //                 ps.close();
   //                 ps=null;
   //             }
     }catch(Exception e){
      System.out.println(e);
     }

     return coll;
    }
    public static String createTreeInfo(List alist){
     StringBuffer contents = new StringBuffer();
     contents.append("<!--/n");
     contents.append("var Tree = new Array;");//create a array in javascript
     TreeInfo info =null;
     for(int max = alist.size(),i=0;i<max;i++){
      info = (TreeInfo)alist.get(i);
      //define elements of array
      contents.append("Tree[");
      contents.append(i);
      contents.append("]=/"");
      contents.append(info.getNodeId());
      contents.append("|");
      contents.append(info.getParentId());
      contents.append("|");
      contents.append(info.getNodeName());
      contents.append("|");
      contents.append(info.getUrl());
      contents.append("/";");
     }
     contents.append("//-->");
     return contents.toString();
    }
    public static void main(String[]args){
     List alist = TreeUtil.retrieveNodeInfos();
   //         TreeInfo info = null;
   //         for(Iterator i = c.iterator();i.hasNext();){
   //             info = (TreeInfo)i.next();
   //             System.out.println("*****" + info.getNodeName());
   //         }
     System.out.println(TreeUtil.createTreeInfo(alist));
    }
   }

3)编写标签类

InitTreeTag.java
package com.diegoyun.web.taglibs;
import com.diegoyun.web.tree.TreeUtil;
import javax.servlet.jsp.tagext.TagSupport;
import javax.servlet.jsp.JspException;
import java.io.IOException;
/**
   * @author Diegoyun
   * @version 1.0
   */
public class InitTreeTag extends TagSupport{
   public int doEndTag() throws JspException {
    StringBuffer tree = new StringBuffer();
    tree.append("<script type=/"text/javascript/">/n");
    tree.append(TreeUtil.createTreeInfo(TreeUtil.retrieveNodeInfos()));
    tree.append("</script>/n");
    try{
     pageContext.getOut().println(tree.toString());
    }catch(IOException ioe){
     ioe.printStackTrace();
    }
    return super.doEndTag();
   }
}
ShowTreeTag.java :
package com.diegoyun.web.taglibs;
import javax.servlet.jsp.tagext.TagSupport;
import javax.servlet.jsp.JspException;
import java.io.IOException;
/**
   * @author Diegoyun
   * @version 1.0
   */
public class ShowTreeTag extends TagSupport{
   public int doEndTag() throws JspException {
    StringBuffer buffer = showTree();
    try {
     pageContext.getOut().println(buffer.toString());
    }
    catch (IOException ioe) {
     ioe.printStackTrace();
    }
    return super.doEndTag();
   }
   private StringBuffer showTree(){
    StringBuffer sb = new StringBuffer();
    sb.append("<div class=/"tree/">/n");
    sb.append("<script type=/"text/javascript/">/n");
    sb.append("<!--/n");
    sb.append("createTree(Tree，1，7);/n");
    sb.append("//-->/n");
    sb.append("</script>/n");
    sb.append("</div>/n");
    return sb;
   }
}

标签的tld如下：

<?xml version="1.0" encoding="ISO-8859-1" ?>
<!DOCTYPE taglib
    PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN"
    "http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd">
<taglib>
   <tlib-version>1.0</tlib-version>
   <jsp-version>1.2</jsp-version>
   <short-name>tree</short-name>
   <!--initTreeTag-->
   <tag>
    <name>init</name>
    <tag-class>com.diegoyun.web.taglibs.InitTreeTag</tag-class>
    <body-content>empty</body-content>
   </tag>
   <!--ShowTreeTag-->
   <tag>
    <name>show</name>
    <tag-class>com.diegoyun.web.taglibs.ShowTreeTag</tag-class>
    <body-content>empty</body-content>
   </tag>
</taglib>

4）建立web过程，编写jsp进行测试。
index.jsp如下：

<%@ page language="java"%>
<%@ taglib uri="/WEB-INF/tlds/tree.tld" prefix="tree"%>

<html>
<head>
   <title>Tree example</title>
   <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
   <link rel="StyleSheet" href="tree.css" type="text/css">
   <script type="text/javascript" src="tree.js"></script>
   <tree:init/>
</head>
<body>

<b>Tree example :</b><br /><br />
<tree:show/>
<br /><br />
</body>
</html>