實現論壇樹型結構的演算法很多，具體你可以去www.chinaasp.com的全文檢索搜尋中查詢。我現在的JSP論壇採用的也是當中的一種：不用遞迴實現樹型結構的演算法，現在我將論壇樹型結構的具體演算法和大家介紹一下，和大家一起交流。
1、示範表的結構：
表名：mybbslist
欄位 資料類型 說明
BBSID 自動編號
RootID Int 根帖ID，本身為根帖則RootID = ID
FID Int 父帖ID，上一層文章的ID，如是根帖則FID = 0
DEPTH Int 根帖Level=0，其他依據回複的深度遞增
BBSSubject Char 主題
2。建立表：
create table mybbslist (
forumID int(20) not null,
bbsID int auto_increment primary key,
rootid int(20) not null,
fid int(20) not null,
depth int(20) not null,
userID int(20) not null,
bbsUser varchar(24) not null,
bbsSubject varchar(100) not null,
bbsContent text,
bbsTime varchar(30),
bbsRead int(20),
bbsReply int(20),
INDEX forumID (forumID)) |
3、串連MYSQL資料庫的BEAN
package netzero;
import java.sql.*;
public class mydb
{
String driverName = "org.gjt.mm.mysql.Driver";
Connection conn = null;
Statement stmt = null;
ResultSet rs = null;
String connURL= "jdbc:mysql://localhost/mybbs?user=root&password=how&useUnicode=true&characterEncode=8859_1";
//String connURL= "jdbc:mysql://localhost/netzerobbs?user=root&password=how";
public mydb()
{
try
{
Class.forName(driverName);
}
catch (java.lang.ClassNotFoundException e)
{
System.err.println("netzero(String): " + e.getMessage());
}
} public ResultSet executeQuery(String sql) throws SQLException
{
conn = DriverManager.getConnection(connURL);
stmt = conn.createStatement();
rs = stmt.executeQuery(sql);
return rs;
} public boolean closeConn()
{
try
{
if (rs!=null) rs.close();
if (stmt!=null) stmt.close();
if (conn!=null) conn.close();
return true;
}
catch ( SQLException ex )
{
System.err.println("closeConn: " + ex.getMessage());
return false;
}
} } |
4、顯示論壇的JSP程式
＜jsp:useBean id="mybbs" scope="session" class="netzero.mydb" /＞
＜%@ page contentType="text/html;charset=gb2312" %＞
＜%@ page import="java.io.*" %＞
＜%@ page import="java.sql.*" %＞
＜%
int intRowCount;
out.print("顯示論壇樹形結構");
out.print("＜br＞＜br＞");
try {
String sql="select * from mybbslist order by rootid desc,depth,fid,bbsid";
ResultSet rs = mybbs.executeQuery(sql);
if (rs.next())
{
rs.last();
intRowCount=rs.getRow();
out.print("論壇樹中有");
out.print(intRowCount);
out.print("個葉子節點");
rs.first();
int j=0;
int Depth = 0;
out.print("＜ul＞");
while(j＜intRowCount)
{
int rsDepth=rs.getInt("Depth");
if (rsDepth＜Depth)
{
for(int i=1;i＜Depth+1;i=i+1)
{
out.print("＜/ul＞");
}
}
rsDepth=rs.getInt("Depth");
if (rsDepth＞Depth)
{
out.print("＜ul＞");
}
out.print("＜li＞"); String bbssubject=rs.getString("bbssubject");
out.print(bbssubject);
out.print("＜/li＞");
Depth = rs.getInt("Depth");
j=j+1;
rs.next();
}
out.print("＜/ul＞");
}
else
{
out.print("資料庫中無記錄");
}
}catch (SQLException E) {
out.println("SQLException: " + E.getMessage());
out.println("SQLState: " + E.getSQLState());
out.println("VendorError: " + E.getErrorCode());
}
%＞
＜% //關閉mysql串連
try {
if(!mybbs.closeConn());
} catch (Exception ex) {
System.err.println("closeConn: " + ex.getMessage());
}
%＞ |
