jsp+ajax实现动态树结构

package org.itfuture.www.ajax; import java.sql.ResultSet; import java.sql.SQLException; import java.util.Vector; public class Category implements TreeviewElement { protected int ID;//代表数据库中category_id列; protected int parentID;//代表数据库中parent_category_id列; protected String categoryName;//代表数据库中category_name列; protected String activeStatus="Y";//代表数据库中active_status列; //无参的构造方法 public Category() { this.ID = -1; } public Category(int id) {//有参的构造方法，参数为portlet_id this.ID = id; if (!FromDb())//如果没有找到该id的porlet this.ID = -1; } public boolean FromDb() {//从数据库中读出，并更新bean int row = -1; //读记录的sql语句 String sql = "select * from product_category where category_id=" + this.ID + " and active_status='Y'"; ResultSet rs = DbManager.getResultSet(sql);//执行sql语句并返回ResultSet try { rs.last();//移动到最后一行 row = rs.getRow();//得到总记录数 if (row == 1) {//如果只查询到一条记录，则代表该记录存在并更新该对象的属性 this.parentID = rs.getInt("PARENT_CATEGORY_ID"); this.categoryName = rs.getString("CATEGORY_NAME"); this.activeStatus = rs.getString("ACTIVE_STATUS"); return true; } else return false; } catch (SQLException e) { e.printStackTrace(); return false; } finally { try {//最后关闭ResutltSet,Statement.并释放连接 if (rs != null) rs.close(); if (rs.getStatement() != null) rs.getStatement().close(); DbManager.releaseConnection(); } catch (SQLException e) { e.printStackTrace(); } } } public String getActiveStatus() { return activeStatus; } public void setActiveStatus(String activeStatus) { this.activeStatus = activeStatus; } public String getCategoryName() { return categoryName; } public void setCategoryName(String categoryName) { this.categoryName = categoryName; } public int getID() { return ID; } public void setID(int id) { ID = id; } public int getParentID() { return parentID; } public void setParentID(int parentID) { this.parentID = parentID; } public String getNodeName() { return getCategoryName(); } public boolean canExpand() { String sql ="select category_id from product_category where parent_category_id="+getID(); ResultSet rs = DbManager.getResultSet(sql);//执行sql语句并返回ResultSet try { rs.last();//移动到最后一行 int row = rs.getRow();//得到总记录数 if (row <= 0) return false; else return true; } catch (SQLException e) { e.printStackTrace(); return false; } finally { try {//最后关闭ResutltSet,Statement.并释放连接 if (rs != null) rs.close(); if (rs.getStatement() != null) rs.getStatement().close(); DbManager.releaseConnection(); } catch (SQLException e) { e.printStackTrace(); } } } public TreeviewElement[] getChildren() { String sql ="select category_id from product_category where parent_category_id="+getID(); ResultSet rs = DbManager.getResultSet(sql);//执行sql语句并返回ResultSet try { rs.last();//移动到最后一行 int row = rs.getRow();//得到总记录数 if (row <= 0) {//如果没有子结点 return null;//返回null } else{//如果有子结点 Vector vData = new Vector(); rs.beforeFirst(); while (rs.next()) vData.add(""+rs.getInt("CATEGORY_ID")); TreeviewElement[] children = new TreeviewElement[vData.size()]; for (int i=0;i<vData.size();i++) { int id = Integer.parseInt((String)vData.get(i)); children[i] = new Category(id); } return children;//返回该记录的所有子结点 } } catch (SQLException e) { e.printStackTrace(); return null; } finally { try {//最后关闭ResutltSet,Statement.并释放连接 if (rs != null) rs.close(); if (rs.getStatement() != null) rs.getStatement().close(); DbManager.releaseConnection(); } catch (SQLException e) { e.printStackTrace(); } } } }