使用dtree构建动态树型菜单

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("");

    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("</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>
  
  <tag>
   <name>init</name>
   <tag-class>com.diegoyun.web.taglibs.InitTreeTag</tag-class>
   <body-content>empty</body-content>
  </tag>
  
  <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>

秒客网

使用dtree构建动态树型菜单

相关文章