菜菜问题:帮忙解释一下这段代码每行的意思 Vector listnews = new Vector(); 这句都不懂的话,还是不要做JSP了,先补补JAVA基础好点其他的估计都是自定义的BEAN,具体的方法要看文档了 解决方案 » 免费领取超大流量手机卡,每月29元包185G流量+100分钟通话, 中国电信官方发货 dispnews.javapackage news.news;import news.database.DBConnect;import news.news.IClass;import java.sql.*;import java.util.*;public class DispClass extends IClass{public ResultSet rs;public DispClass(){};/** 得到所有栏目*/public Vector allClass() { DBConnect dbc = null; Vector allClassVector = new Vector(); try{ dbc = new DBConnect(); dbc.prepareStatement("SELECT * FROM class order by id"); rs = dbc.executeQuery(); while(rs.next()){ IClass iclass = new IClass(); iclass.setID(rs.getInt("id")); iclass.setName(rs.getString("name")); iclass.setMaster(rs.getString("master")); allClassVector.add(iclass); } }catch(Exception e){ System.err.println(e); }finally{ try{ dbc.close(); }catch(Exception e){ e.printStackTrace(); } } return allClassVector;}/** 根据ID得到栏目*/public IClass idToClass() { DBConnect dbc = null; IClass iclass = new IClass(); try{ dbc = new DBConnect(); dbc.prepareStatement("SELECT * FROM class WHERE id = ?"); dbc.setInt(1,ID); rs = dbc.executeQuery(); if(rs.next()){ iclass.setID(rs.getInt("id")); iclass.setName(rs.getString("name")); iclass.setMaster(rs.getString("master")); } }catch(Exception e){ System.err.println(e); }finally{ try{ dbc.close(); }catch(Exception e){ e.printStackTrace(); } } return iclass;}/** 计算栏目的总数*/public int classNum() { DBConnect dbc = null; int classCount = 0; try{ dbc = new DBConnect(); dbc.prepareStatement("SELECT count(*) FROM class"); rs = dbc.executeQuery(); if(rs.next()) classCount = rs.getInt(1); }catch(Exception e){ System.err.println(e); }finally{ try{ dbc.close(); }catch(Exception e){ e.printStackTrace(); } } return classCount;}} dispclass.javapackage news.news;import news.database.DBConnect;import news.news.IClass;import java.sql.*;import java.util.*;public class DispClass extends IClass{public ResultSet rs;public DispClass(){};/** 得到所有栏目*/public Vector allClass() { DBConnect dbc = null; Vector allClassVector = new Vector(); try{ dbc = new DBConnect(); dbc.prepareStatement("SELECT * FROM class order by id"); rs = dbc.executeQuery(); while(rs.next()){ IClass iclass = new IClass(); iclass.setID(rs.getInt("id")); iclass.setName(rs.getString("name")); iclass.setMaster(rs.getString("master")); allClassVector.add(iclass); } }catch(Exception e){ System.err.println(e); }finally{ try{ dbc.close(); }catch(Exception e){ e.printStackTrace(); } } return allClassVector;}/** 根据ID得到栏目*/public IClass idToClass() { DBConnect dbc = null; IClass iclass = new IClass(); try{ dbc = new DBConnect(); dbc.prepareStatement("SELECT * FROM class WHERE id = ?"); dbc.setInt(1,ID); rs = dbc.executeQuery(); if(rs.next()){ iclass.setID(rs.getInt("id")); iclass.setName(rs.getString("name")); iclass.setMaster(rs.getString("master")); } }catch(Exception e){ System.err.println(e); }finally{ try{ dbc.close(); }catch(Exception e){ e.printStackTrace(); } } return iclass;}/** 计算栏目的总数*/public int classNum() { DBConnect dbc = null; int classCount = 0; try{ dbc = new DBConnect(); dbc.prepareStatement("SELECT count(*) FROM class"); rs = dbc.executeQuery(); if(rs.next()) classCount = rs.getInt(1); }catch(Exception e){ System.err.println(e); }finally{ try{ dbc.close(); }catch(Exception e){ e.printStackTrace(); } } return classCount;}} Vector listnews = new Vector(); 是什么意思? 首页显示新闻的vector那段不知道是做什么用的? Vector listnews = new Vector(); vector 简单的说就是个容器,对象的容器 首页代码 <% listclass = dispclass.allClass(); for(int i=0;i<listclass.size();i++) { IClass classinfo = (IClass)listclass.elementAt(i); %> ·<FONT color=#990000>【<A href="list.jsp?id=<%=classinfo.getID()%>"><%=classinfo.getName()%></A>】</FONT><BR> <% Vector listnews = new Vector(); DispNews dispnews = new DispNews(); dispnews.setRootID(classinfo.getID()); listnews = dispnews.rootidToNews(); dispnews.setRootID(classinfo.getID()); int newsnum=dispnews.newsNum(); //System.out.println("newsnum:"+newsnum);%> <% for(int j=0;j<listnews.size();j++) { News newsinfo = (News)listnews.elementAt(j); if(j>9){continue;}%> <A href="news.jsp?id=<%=newsinfo.getID()%>" target=_blank title=<%=newsinfo.getTopic()%>> <% if(newsinfo.getTopic().length()>30) out.println(newsinfo.getTopic().substring(0,30)+"..."); else out.println(newsinfo.getTopic());%></A><font color=#999999><%=newsinfo.getAdddate()%></font><BR> <%}%><TABLE align=right><TR><TD><A HREF="list.jsp?id=<%=classinfo.getID()%>">more...</A></TD></TR></TABLE><BR><%}%> </TD> 我对Java也不是很熟。Vector的意思是‘向量,矢量,无线电导引’。Vector listnews = new Vector();是实例化一个类吧。 头晕Vector是一个向量,在java中是用来存放对象的集合的 服务器运行过长,jsp不响应 我访问我的一个jsp页面的时候为什么总是 变成了Debug JSP设计的在线考试系统--填空题 出一个计算题 mysql4.1.18在linux系统下为什么不支持java的预编译sql语法? 为什么没有生成log4j的文件日志?? 关于servlet的filter映射问题 又是java的中文问题! innerHTML的使用问题,急,在线等答案。 tomcat5.0如何正确配置? 请问怎么配置tomcat5.0连接到sql server2000数据库 新手上路:环境配置问题
import news.news.IClass;
import java.sql.*;
import java.util.*;public class DispClass extends IClass{public ResultSet rs;public DispClass(){};/*
* 得到所有栏目
*/
public Vector allClass() {
DBConnect dbc = null;
Vector allClassVector = new Vector();
try{
dbc = new DBConnect();
dbc.prepareStatement("SELECT * FROM class order by id");
rs = dbc.executeQuery();
while(rs.next()){
IClass iclass = new IClass();
iclass.setID(rs.getInt("id"));
iclass.setName(rs.getString("name"));
iclass.setMaster(rs.getString("master"));
allClassVector.add(iclass);
}
}catch(Exception e){
System.err.println(e);
}finally{
try{
dbc.close();
}catch(Exception e){
e.printStackTrace();
}
}
return allClassVector;
}/*
* 根据ID得到栏目
*/
public IClass idToClass() {
DBConnect dbc = null;
IClass iclass = new IClass();
try{
dbc = new DBConnect();
dbc.prepareStatement("SELECT * FROM class WHERE id = ?");
dbc.setInt(1,ID);
rs = dbc.executeQuery();
if(rs.next()){
iclass.setID(rs.getInt("id"));
iclass.setName(rs.getString("name"));
iclass.setMaster(rs.getString("master"));
}
}catch(Exception e){
System.err.println(e);
}finally{
try{
dbc.close();
}catch(Exception e){
e.printStackTrace();
}
}
return iclass;
}/*
* 计算栏目的总数
*/
public int classNum() {
DBConnect dbc = null;
int classCount = 0;
try{
dbc = new DBConnect();
dbc.prepareStatement("SELECT count(*) FROM class");
rs = dbc.executeQuery();
if(rs.next()) classCount = rs.getInt(1);
}catch(Exception e){
System.err.println(e);
}finally{
try{
dbc.close();
}catch(Exception e){
e.printStackTrace();
}
}
return classCount;
}}
import news.news.IClass;
import java.sql.*;
import java.util.*;public class DispClass extends IClass{public ResultSet rs;public DispClass(){};/*
* 得到所有栏目
*/
public Vector allClass() {
DBConnect dbc = null;
Vector allClassVector = new Vector();
try{
dbc = new DBConnect();
dbc.prepareStatement("SELECT * FROM class order by id");
rs = dbc.executeQuery();
while(rs.next()){
IClass iclass = new IClass();
iclass.setID(rs.getInt("id"));
iclass.setName(rs.getString("name"));
iclass.setMaster(rs.getString("master"));
allClassVector.add(iclass);
}
}catch(Exception e){
System.err.println(e);
}finally{
try{
dbc.close();
}catch(Exception e){
e.printStackTrace();
}
}
return allClassVector;
}/*
* 根据ID得到栏目
*/
public IClass idToClass() {
DBConnect dbc = null;
IClass iclass = new IClass();
try{
dbc = new DBConnect();
dbc.prepareStatement("SELECT * FROM class WHERE id = ?");
dbc.setInt(1,ID);
rs = dbc.executeQuery();
if(rs.next()){
iclass.setID(rs.getInt("id"));
iclass.setName(rs.getString("name"));
iclass.setMaster(rs.getString("master"));
}
}catch(Exception e){
System.err.println(e);
}finally{
try{
dbc.close();
}catch(Exception e){
e.printStackTrace();
}
}
return iclass;
}/*
* 计算栏目的总数
*/
public int classNum() {
DBConnect dbc = null;
int classCount = 0;
try{
dbc = new DBConnect();
dbc.prepareStatement("SELECT count(*) FROM class");
rs = dbc.executeQuery();
if(rs.next()) classCount = rs.getInt(1);
}catch(Exception e){
System.err.println(e);
}finally{
try{
dbc.close();
}catch(Exception e){
e.printStackTrace();
}
}
return classCount;
}}
vector 简单的说就是个容器,对象的容器
for(int i=0;i<listclass.size();i++) {
IClass classinfo = (IClass)listclass.elementAt(i); %>
·<FONT color=#990000>【<A href="list.jsp?id=<%=classinfo.getID()%>"><%=classinfo.getName()%></A>】</FONT><BR>
<% Vector listnews = new Vector();
DispNews dispnews = new DispNews();
dispnews.setRootID(classinfo.getID());
listnews = dispnews.rootidToNews();
dispnews.setRootID(classinfo.getID());
int newsnum=dispnews.newsNum();
//System.out.println("newsnum:"+newsnum);%> <% for(int j=0;j<listnews.size();j++) {
News newsinfo = (News)listnews.elementAt(j);
if(j>9){continue;}%>
<A href="news.jsp?id=<%=newsinfo.getID()%>" target=_blank
title=<%=newsinfo.getTopic()%>>
<% if(newsinfo.getTopic().length()>30)
out.println(newsinfo.getTopic().substring(0,30)+"...");
else
out.println(newsinfo.getTopic());%></A><font
color=#999999><%=newsinfo.getAdddate()%></font><BR>
<%}%><TABLE align=right><TR><TD><A HREF="list.jsp?id=<%=classinfo.getID()%>">more...</A></TD></TR></TABLE><BR><%}%>
</TD>
Vector listnews = new Vector();是实例化一个类吧。
Vector是一个向量,在java中是用来存放对象的集合的