JSP树形菜单的实现(转载)
(2009-04-20 15:21:03)
转载
标签:
分类:技术讲解
杂谈
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:https://www.doczj.com/doc/786042711.html,/javascripts/tree/
以下是dtree的用法示例:
1)初始化菜单
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 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;
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;
public class InitTreeTag extends TagSupport{
public int doEndTag() throws JspException {
StringBuffer tree = new StringBuffer();
tree.append("\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;
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("
sb.append("\n");
sb.append("
return sb;
}
}
标签的tld如下:
PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN" "https://www.doczj.com/doc/786042711.html,/dtd/web-jsptaglibrary_1_2.dtd">
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"%>
Tree example :
https://www.doczj.com/doc/786042711.html, TreeView树型菜单操作实例(代码调试通过) 本实例完成TreeView树型菜单添加,修改,删除,绑定DropDownList功能,移动功能读者可以自行书写.aspx代码