树形菜单的实现.doc

JSP树形菜单的实现(转载)(2009-04-20 15:21:03) 转载标签： 杂谈分类： 技术讲解 1。原理简介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。下载目录：/javascripts/tree/以下是dtree的用法示例：1）初始化菜单!-var Tree = new Array;Tree0 = 1|0|Page 1|#;Tree1 = 2|1|Page 1.1|#;Tree2 = 3|1|Page 1.2|#;Tree3 = 4|3|Page 1.2.1|#;2）调用函数显然，如果用动态的脚本来初始化菜单数组（asp,jsp均可），那就可以很方便的实现动态的树型菜单了。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;public class TreeInfo private int nodeId = -1;/node idprivate int parentId = -1;/parentIdprivate String nodeName = null;/node nameprivate String url = null;/url referencespublic 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;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;tryClass.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 javascriptTreeInfo info =null;for(int max = alist.size(),i=0;i);return contents.toString();public static void main(Stringargs)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.javapackage 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;public class InitTreeTag extends TagSupportpublic int doEndTag() throws JspException StringBuffer tree = new StringBuffer();tree.append(n);tree.append(TreeUtil.createTreeInfo(TreeUtil.retrieveNodeInfos();tree.append(n);trypageContext.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;public class ShowTreeTag extends TagSupportpublic 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(n);sb.append(n);sb.ap