java实现无限级分类树形，连接mysql数据库

package book.treeview; import java.sql.ResultSet; import java.sql.SQLException; import java.util.Vector; public class treeviewRender { static public String renderStatic(TreeviewElement treeElmt, boolean bHidden) { StringBuffer content = new StringBuffer(); content.append("<li id=" + treeElmt.getID() + ">");//显示li元素 if (bHidden && treeElmt.canExpand())//如果可以展开并且初始化为隐藏,则显示展开图片，并添加showHide事件 content.append("<img src=images/plus.gif onClick=\"showHide('" + treeElmt.getID() + "')\">"); else if (treeElmt.canExpand())//如果可以展开,则显示折叠图片，并添加showHide事件 content.append("<img src=images/minus.gif onClick=\"showHide('" + treeElmt.getID() + "')\">"); else//否则显示空白图片 content.append("<img src=images/blank.gif>"); content.append("<img src=images/folder.gif><a href=\"#\"");//添加文件夹图片 if (treeElmt.canExpand())//如果可以展开，为节点添加showHide事件 content.append("onClick=\"showHide('" + treeElmt.getID() + "')\""); content.append(">" + treeElmt.getNodeName() + "</a>"); if (treeElmt.canExpand()) {//如果可以展开，则用UL标记显示子结点 content.append("<ul"); if (bHidden) content.append(" style=\"display:none;\" "); content.append(">"); TreeviewElement[] elmts = treeElmt.getChildren();//获得此结点的子节点 for (int i = 0; i < elmts.length; i++) content.append(renderStatic(elmts[i], bHidden));//递归调用显示子节点 content.append("</ul>"); } content.append("</li>");//结束显示<li>元素 return content.toString(); } static public TreeviewElement[] getTopCategory() {//得到父类id为0的子类集合 String sql = "select category_id from product_category where parent_category_id=0"; 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 null; } else { 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; } } 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(); } } } static public String renderSimple(TreeviewElement treeElmt) {//循环显示父类下的所有子类集合 StringBuffer content = new StringBuffer(); content.append("<li id=" + treeElmt.getID() + "><a href=\"#\">"); content.append( treeElmt.getNodeName() + "</a>"); if (treeElmt.canExpand()) { content.append("<ul>"); TreeviewElement[] elmts = treeElmt.getChildren(); for (int i = 0; i < elmts.length; i++) content.append(renderSimple(elmts[i])); content.append("</ul>"); } content.append("</li>"); return content.toString(); } static public String renderTreeViewAjax(TreeviewElement treeElmt,boolean bRenderChildren) { StringBuffer content = new StringBuffer(); content.append("<li id="+treeElmt.getID()+">"); if (treeElmt.canExpand()) content.append("<img src=images/plus.gif onClick=\"getSubTree('"+treeElmt.getID()+"')\">"); else content.append("<img src=images/blank.gif>"); content.append("<img src=images/folder.gif><a href=\"#\""); if (treeElmt.canExpand()) content.append(" onClick=\"getSubTree('"+treeElmt.getID()+"')\""); content.append(">"+treeElmt.getNodeName()+"</a>"); if ( bRenderChildren&&treeElmt.canExpand( )) { content.append("<ul>"); TreeviewElement[] elmts = treeElmt.getChildren(); for (int i=0;i<elmts.length;i++) content.append(renderTreeViewAjax(elmts[i],false)); content.append("</ul>"); } content.append("</li>"); return content.toString(); } }