public class OS {
public static final String CLASS_PATH;
public static final boolean isLinux;
static {
URL resource = OS.class.getResource("OS.class");
String classPath = resource.getPath();
String className = OS.class.getName().replace('.', '/') + ".class";
String classesPath = classPath.substring(0, classPath.indexOf(className));
if (System.getProperty("os.name").toUpperCase().indexOf("WINDOWS") != -1&& classesPath.startsWith("/")) {
classesPath = classesPath.substring(1);
isLinux = false;
} else {
isLinux = true;
}
CLASS_PATH = classesPath;
}
public static void main(String arg[]){
System.out.println(OS.isLinux);
}
}
]]>
import="java.util.*" pageEncoding="GBK"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=GBK">
<title>Insert title here</title>
</head>
<body>
<%
out.print("<br>"+"session is new:"+session.isNew());
Date created = new Date(session.getCreationTime());
//得到session对象创徏的时?br />Date accessed = new Date(session.getLastAccessedTime());
//得到最后访问该session对象的时?br />out.println("<br>"+"ID " + session.getId()+" ");
//得到该session的idQƈ打印
out.println("<br>"+"Created: " + created+" ");
//打印session创徏旉
out.println("<br>"+"Last Accessed: " + accessed+" ");
//打印最后访问时?/p>
session.setAttribute("Name","Tom");
//在session中添加变量Name=Tom
session.setAttribute("UID","12345678");
//在session中添加变量UID=12345678
Enumeration e = session.getAttributeNames();
//得到session中变量名的枚丑֯?br />while (e.hasMoreElements()) { //遍历每一个变?br />String name = (String)e.nextElement(); //首先得到名字
String value = session.getAttribute(name).toString();
//由名字从session中得到?br />out.println("<br>"+name + " = " + value+" "); //打印
}
%>
</body>
</html>
]]>
- <%@ page
- import = "java.awt.*,java.awt.image.*,java.util.*,javax.imageio.*" %>
- <%@ page import = "java.io.OutputStream" %>
- <%@ page pageEncoding= "UTF-8" %>
- <%!Color getRandColor( int fc, int bc) {
- Random random = new Random();
- if (fc > 255 )
- fc = 255 ;
- if (bc > 255 )
- bc = 255 ;
- int r = fc + random.nextInt(bc - fc);
- int g = fc + random.nextInt(bc - fc);
- int b = fc + random.nextInt(bc - fc);
- return new Color(r, g, b);
- }%>
- <%
- try {
- response.setHeader( "Pragma" , "No-cache" );
- response.setHeader( "Cache-Control" , "no-cache" );
- response.setDateHeader( "Expires" , 0 );
- int width = 60 , height = 20 ;
- BufferedImage image = new BufferedImage(width, height,
- BufferedImage.TYPE_INT_RGB);
- OutputStream os = response.getOutputStream();
- Graphics g = image.getGraphics();
- Random random = new Random();
- g.setColor(getRandColor( 200 , 250 ));
- g.fillRect( 0 , 0 , width, height);
- g.setFont( new Font( "Times New Roman" , Font.PLAIN, 18 ));
- g.setColor(getRandColor( 160 , 200 ));
- for ( int i = 0 ; i < 155 ; i++) {
- int x = random.nextInt(width);
- int y = random.nextInt(height);
- int xl = random.nextInt( 12 );
- int yl = random.nextInt( 12 );
- g.drawLine(x, y, x + xl, y + yl);
- }
- String sRand = "" ;
- for ( int i = 0 ; i < 4 ; i++) {
- String rand = String.valueOf(random.nextInt( 10 ));
- sRand += rand;
- g.setColor( new Color( 20 + random.nextInt( 110 ), 20 + random
- .nextInt( 110 ), 20 + random.nextInt( 110 )));
- g.drawString(rand, 13 * i + 6 , 16 );
- }
- session.setAttribute( "rand" , sRand);
- g.dispose();
- ImageIO.write(image, "JPEG" , os);
- os.flush();
- os.close();
- os = null ;
- response.flushBuffer();
- out.clear();
- out = pageContext.pushBody();
- } catch (IllegalStateException e) {
- System.out.println(e.getMessage());
- e.printStackTrace();
- }
- %>
]]>
]]>
目l构图：
index.jsp:
<html>
<head>
<title>My JSP 'index.jsp' starting page</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<SCRIPT type="text/javascript">
var req;
window.onload=function(){
}
function Change_Select()
{
var zhi=document.getElementById('hero').value;
var url="select?id="+escape(zhi);
if(window.XMLHttpRequest)
{
req=new XMLHttpRequest();
}else if(window.ActiveXObject)
{
req=new ActiveXObject("Microsoft.XMLHTTP");
}
if(req)
{
req.open("GET",url,true);
req.onreadystatechange=callback;
req.send(null);
}
}
function callback()
{
if(req.readyState == 4)
{
if(req.status == 200)
{
parseMessage();
}else{
alert("Not able to retrieve description"+req.statusText);
}
}
}
function parseMessage()
{
var xmlDoc=req.responseXML.documentElement;
var xSel=xmlDoc.getElementsByTagName('select');
var select_root=document.getElementById('skill');
select_root.options.length=0;
for(var i=0;i<xSel.length;i++)
{
var xValue=xSel[i].childNodes[0].firstChild.nodeValue;
var xText=xSel[i].childNodes[1].firstChild.nodeValue;
var option=new Option(xText,xValue);
try{
select_root.add(option);
}catch(e){
}
}
}
</SCRIPT>
</head>
<body>
<div align="center">
<form name="form1" method="post" action="">
<TABLE width="70%" boder="0" cellspacing="0">
<TR>
<TD align="center">Double Select Box</TD>
</TR>
<TR>
<TD>
<SELECT name="hero" id="hero" onChange="Change_Select()">
<OPTION value="0">Unbounded</OPTION>
<OPTION value="1">D.K.</OPTION>
<OPTION value="2">NEC.</OPTION>
<OPTION value="3">BOSS</OPTION>
</SELECT>
<SELECT name="skill" id="skill">
<OPTION value="0">Unbounded</OPTION>
</SELECT>
</TD>
</TR>
<TR><td> </td></TR>
</TABLE>
</form>
</div>
</body>
</html>
SelectServlet.java:
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class SelectServlet extends HttpServlet {
/**
* Constructor of the object.
*/
public SelectServlet() {
super();
}
/**
* Destruction of the servlet. <br>
*/
public void destroy() {
super.destroy(); // Just puts "destroy" string in log
// Put your code here
}
/**
* The doGet method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to get.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/xml");
response.setHeader("Cache-Control","no-cache");
String targetId=request.getParameter("id").toString();
String xml_start="<selects>";
String xml_end="</selects>";
String xml="";
if(targetId.equalsIgnoreCase("0")){
xml="<select><value>0</value><text>Unbounded</text></select>";
}else if(targetId.equalsIgnoreCase("1")){
xml="<select><value>1</value><text>Mana Burn</text></select>";
xml +="<select><value>2</value><text>Death Coil</text></select>";
xml +="<select><value>3</value><text>Unholy Aura</text></select>";
xml +="<select><value>4</value><text>Unholy Fire</text></select>";
}else if(targetId.equalsIgnoreCase("2")){
xml="<select><value>1</value><text>Corprxplode</text></select>";
xml +="<select><value>2</value><text>Raise Dead</text></select>";
xml +="<select><value>3</value><text>Brilliance Aura</text></select>";
xml +="<select><value>4</value><text>Aim Aura</text></select>";
}else{
xml="<select><value>1</value><text>Rain of Chaos</text></select>";
xml +="<select><value>2</value><text>Finger of Death</text></select>";
xml +="<select><value>3</value><text>Bash</text></select>";
xml +="<select><value>4</value><text>Summon Doom</text></select>";
}
String last_xml=xml_start+xml+xml_end;
response.getWriter().write(last_xml);
}
/**
* The doPost method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to post.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request,response);
}
/**
* Initialization of the servlet. <br>
*
* @throws ServletException if an error occure
*/
public void init() throws ServletException {
// Put your code here
}
}
web.xml:
<web-app version="2.4"
xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<servlet>
<servlet-name>SelectServlet</servlet-name>
<servlet-class>com.SelectServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>SelectServlet</servlet-name>
<url-pattern>/select</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
q行l果图：
]]>
d所有的文g数据
<%@ page contentType="text/html;charset=gb2312"%>
<%@ page import="java.io.*,java.lang.*"%>
<html>
<head>
<title>d所有的文g数据</title>
</head>
<body>
<%
String path=request.getRealPath(".");
FileReader fr=new FileReader(path + "file://ReadData.txt/");
//关键在于dq程中，要判断所d的字W是否已l到了文件的末尾Qƈ且这个字W是不是文g中的断行W，卛_断该字符值是否ؓ13?br />int c=fr.read();//从文件中d一个字W?br />//判断是否已读到文件结?br />while(c!=-1){
out.print((char)c);//输出d的数?br /> c=fr.read();//从文件中l箋d数据
if(c==13){//判断是否为断行字W?br /> out.print("<br>");//输出分行标签
fr.skip(1);//略过一个字W?br /> //c=fr.read();//d一个字W?br /> }
}
fr.close();
%>
</body>
</html>
一行一行读取数?br /><%@ page contentType="text/html;charset=gb2312"%>
<%@ page import="java.io.*"%>
<html>
<head>
<title>文gd</title>
</head>
<body>
<%
String path=request.getRealPath("");//取得当前目录的\?br /> FileReader fr=new FileReader(path + "file://file//inc//t.txt%22);//建立FileReader对象Qƈ实例化ؓfr
BufferedReader br=new BufferedReader(fr);//建立BufferedReader对象Qƈ实例化ؓbr
String Line=br.readLine();//从文件读取一行字W串
//判断d到的字符串是否不为空
while(Line!=null){
out.println(Line + "<br>");//输出从文件中d的数?br /> Line=br.readLine();//从文件中l箋d一行数?br /> }
br.close();//关闭BufferedReader对象
fr.close();//关闭文g
%>
</body>
</html>
略过文g中的字符不读?br /><%@ page contentType="text/html;charset=gb2312"%>
<%@ page import="java.io.*"%>
<html>
<head>
<title>略过字节不读?lt;/title>
</head>
<body>
<%
String path=request.getRealPath(".");
FileReader fr=new FileReader(path + "file://ReadData.txt/");
fr.skip(2);//跌2个字?br />int c=fr.read();//d一个字?br />while(c!=-1){
out.print((char)c);
c=fr.read();
}
fr.close();
%>
</body>
</html>
数据写入文?br /><%@ page contentType="text/html;charset=gb2312"%>
<%@ page import="java.io.*"%>
<html>
<head>
<title>数据写入文?lt;/title>
</head>
<body>
<%
String path=request.getRealPath(".");
FileWriter fw=new FileWriter(path + "file://WriteData.txt%22);//建立FileWriter对象Qƈ实例化fw
//字W串写入文g
fw.write("大家好！");
fw.write("本书是《JSP~程技巧?);
fw.write("请多多指教！");
fw.write("email:stride@sina.com");
fw.close();
FileReader fr=new FileReader(path + "file://WriteData.txt/");
BufferedReader br=new BufferedReader(fr);//建立BufferedReader对象Qƈ实例化ؓbr
String Line=br.readLine();
//d一行数?br />out.println(Line + "<br>");
br.close();//关闭BufferedReader对象
fr.close();
%>
</body>
</html>
写入文件的数据分行
<%@ page contentType="text/html;charset=gb2312"%>
<%@ page import="java.io.*"%>
<html>
<head>
<title>写入文件的数据分行</title>
</head>
<body>
<%
String path=request.getRealPath(".");
FileWriter fw=new FileWriter(path + "file://WriteData.txt/");
BufferedWriter bw=new BufferedWriter(fw);
bw.write("大家好！");
bw.write("本书是《JSP~程技巧》?);
bw.newLine();//断行
bw.write("请多多指教！");
bw.newLine();//断行
bw.write("email: stride@sina.com");
bw.flush();//数据更新至文g
fw.close();//关闭文g?br />out.println("写入文g内容为：<br>");
FileReader fr=new FileReader(path + "file://WriteData.txt/");
BufferedReader br=new BufferedReader(fr);
String Line=br.readLine();//d一行数?br />while(Line!=null){
out.println(Line + "<br>");
Line=br.readLine();
}
fr.close();
%>
</body>
</html>
如何数据追加写入到文g
<%@ page contentType="text/html;charset=gb2312"%>
<%@ page import="java.io.*"%>
<html>
<head>
<title>写入文件的数据分行</title>
</head>
<body>
<%
String path=request.getRealPath(".");
RandomAccessFile rf=new RandomAccessFile(path + "file://WriteData.txt%22,%22rw%22);//定义一个类RandomAccessFile的对象，q实例化
rf.seek(rf.length());//指针移动到文g末尾
rf.writeBytes("\nAppend a line to the file!");
rf.close();//关闭文g?br />out.println("写入文g内容为：<br>");
FileReader fr=new FileReader(path + "file://WriteData.txt/");
BufferedReader br=new BufferedReader(fr);//d文g的BufferedRead对象
String Line=br.readLine();
while(Line!=null){
out.println(Line + "<br>");
Line=br.readLine();
}
fr.close();//关闭文g
%>
</body>
</html>
import java.util.*;
import java.io.*;
public class ReadIni
{
public static void main(String[] args)
throws Exception
{
Properties proDB = new Properties();
FileInputStream in = new FileInputStream("DBConfig.ini");
proDB.load(in);
String jdbc = proDB.getProperty("jdbc");
String dburl = proDB.getProperty("dburl");
String userid = proDB.getProperty("userid");
String password = proDB.getProperty("password");
System.out.println(jdbc);
System.out.println(dburl);
System.out.println(userid);
System.out.println(password);
}
}
DBConfig.ini:
dburl=jdbcracle:thin:@202.16.147.104:1521ub
userid=user
password=password
jdbc=oracle.jdbc.driver.OracleDriver
]]>
<%
//分页昄
int num = 0;
int countall = infolist.size();//L
int pageSize = 28;//每页数量
int pageCount;//d|
int pageNo = 1;//当前号
int mixNum; //当前|据开始号
int maxNum;
String pNO = request.getParameter("pageNo");
if((pNO != null) && (!pNO.equals(""))){
pageNo=Integer.parseInt(pNO);
}
if (countall > pageSize) {
if ((countall / pageSize) * pageSize < countall) {
pageCount = (countall / pageSize) + 1;
}
else{
pageCount = (countall / pageSize);
}
}
else if (countall / pageSize == 1) {
pageCount = 1;
}
else {
pageCount = 1;
}
if (pageNo >= pageCount) {
pageNo = pageCount;
}
else if (pageNo < 1) {
pageNo = 1;
}
mixNum = (pageNo-1) * pageSize;
maxNum = pageNo*pageSize;
if((mixNum + pageSize) > countall){
maxNum = countall;
}
else{
maxNum = mixNum+pageSize;
}
%>
---------------------------------------------------------------------------------------------
<html>
<head>
<script language="JavaScript" type="text/JavaScript">
function check(){
if(Jtrim(document.forms.meslistForm.textfield.value)==""){
alert("误入页?);
}
else if(checkNum(document.forms.meslistForm.textfield.value)){
window.location.href="?pageNo="+document.forms.meslistForm.textfield.value;
}else{
alert("误入数字?);
}
document.forms.meslistForm.textfield.value = "";
document.forms.meslistForm.textfield.select();
}
function checkNum(str){
return str.match(/\D/)==null;
}
function Jtrim(str)
{
var i = 0;
var len = str.length;
if ( str == "" ) return( str );
j = len -1;
flagbegin = true;
flagend = true;
while ( flagbegin == true && i< len)
{
if ( str.charAt(i) == " " )
{
i=i+1;
flagbegin=true;
}
else
{
flagbegin=false;
}
}
while (flagend== true && j>=0)
{
if (str.charAt(j)==" ")
{
j=j-1;
flagend=true;
}
else
{
flagend=false;
}
}
if ( i > j ) return ("")
trimstr = str.substring(i,j+1);
return trimstr;
}</script>
</head>
<body>
<%
for(int i=mixNum;i<maxNum;i++){
//此处用list循环下标用i
}
%>
<table align="center" width="100%" border="0" cellspacing="0" cellpadding="0">
<tr>
<td width="4%" height="27" align="center" valign="middle"
class="word"> </td>
<td width="56%" align="center" valign="middle" class="word"><img
src="<%=path%>/images/pagination/list_home.gif" width="13"
height="13"> <%
if (pageNo > 1) {
%> <a href="?pageNo=1"> 首页</a>
<%
}else{
%> 首页 <%
}
%> <img src="<%=path%>/images/pagination/list_pre.gif"
width="13" height="13"> <%
if (pageNo > 1) {
%> <a href="?pageNo=<%=(pageNo-1)%>"> 前一?lt;/a>
<%
}else{
%> 前一?amp;nbsp; <%
}
%> <img
src="<%=path%>/images/pagination/list_next.gif" width="13"
height="13"> <%
if (pageCount>pageNo) {
%> <a href="?pageNo=<%=(pageNo+1)%>"> 后一?lt;/a>
<%
}else{
%> 后一?amp;nbsp; <%
}
%> <img src="<%=path%>/images/pagination/list_end.gif"
width="13" height="13"> <%
if (pageCount>pageNo) {
%> <a href="?pageNo=<%=(pageCount)%>"> N</a> <%
}else{
%> N <%
}
%>
<td width="26%" align="center" valign="middle" class="word">?lt;%=pageCount%>?amp;nbsp;W?lt;%=pageNo%>?amp;nbsp;
跌{</td>
<td width="4%" align="center" valign="middle" class="word"><input
name="textfield" type="text" class="input" size="1"></td>
<td width="6%" align="center" valign="middle" class="word"><a
href="javascript:check()"><img
src="<%=path%>/images/pagination/go.gif" border="0" width="18"
height="18"></a></td>
<td width="4%" align="left" valign="middle" class="word"> </td>
</tr>
</table></body>
</html>
]]>
因此比较好的分页做法应该是每ơ翻늚时候只从数据库里检索页面大的块区的数据。这栯然每ơ翻都需要查询数据库Q但查询出的记录数很，|络传输数据量不大，如果使用q接池更可以略过最耗时的徏立数据库q接q程。而在数据库端有各U成熟的优化技术用于提高查询速度Q比在应用服务器层做~存有效多了?/p>
在oracle数据库中查询l果的行号用伪列ROWNUM表示Q从1开始）。例如select * from employee where rownum<10 q回?0条记录。但因ؓrownum是在查询之后排序之前赋值的Q所以查询employee按birthday排序的第100?20条记录应该这么写Q?br />[pre] select * from (
select my_table.*, rownum as my_rownum from (
select name, birthday from employee order by birthday
) my_table where rownum <120
) where my_rownum>=100
[/pre]
mySQL可以使用LIMIT子句Q?br /> select name, birthday from employee order by birthday LIMIT 99,20
DB2有rownumber()函数用于获取当前行数?br /> SQL Server没研I过Q可以参考这文章：http://www.csdn.net/develop/article/18/18627.shtm
在WebE序中分会被频J用，但分늚实现l节却是~程q程中比较麻烦的事情。大多分|C的查询操作都同旉要处理复杂的多重查询条gQsql语句需要动态拼接组成，再加上分需要的记录定位、总记录条数查询以及查询结果的遍历、封装和昄Q程序会变得很复杂ƈ且难以理解。因此需要一些工L化分代码，使程序员专注于业务逻辑部分。下面是我设计的两个工具c：
PagedStatement 装了数据库q接、总记录数查询、分|询、结果数据封装和关闭数据库连接等操作Qƈ使用了PreparedStatement支持动态设|参数?br /> RowSetPage 参考PetStore的page by page iterator模式Q?设计RowSetPage用于装查询l果Q用OracleCachedRowSet~存查询出的一|据，关于使用CachedRowSet装数据库查询结果请参考JSP面查询昄常用模式Q以及当前页码、总记录条数、当前记录数{信息， q且可以生成单的HTML分页代码?br /> PagedStatement 查询的结果封装成RowsetPage?/p>
下面是简单的使用CZQ?/p>
//DAO查询数据部分代码Q?
?
public RowSetPage getEmployee(String gender, int pageNo) throws Exception{
String sql="select emp_id, emp_code, user_name, real_name from employee where gender =?";
//使用Oracle数据库的分页查询实现,每页昄5?
PagedStatement pst =new PagedStatementOracleImpl(sql, pageNo, 5);
pst.setString(1, gender);
return pst.executeQuery();
}
//Servlet处理查询h部分代码Q?
?
int pageNo;
try{
//可以通过参数pageno获得用户选择的页?
pageNo = Integer.parseInt(request.getParameter("pageno") );
}catch(Exception ex){
//默认为第一?
pageNo=1;
}
String gender = request.getParameter("gender" );
request.setAttribute("empPage", myBean.getEmployee(gender, pageNo) );
?
//JSP昄部分代码
<%@ page import = "page.RowSetPage"%>
?
<script language="javascript">
function doQuery(){
form1.actionType.value="doQuery";
form1.submit();
}
</script>
?
<form name=form1 method=get>
<input type=hidden name=actionType>
性别Q?
<input type=text name=gender size=1 value="<%=request.getParameter("gender")%>">
<input type=button value=" 查询 " onclick="doQuery()">
<%
RowSetPage empPage = (RowSetPage)request.getAttribute("empPage");
if (empPage == null ) empPage = RowSetPage.EMPTY_PAGE;
%>
?
<table cellspacing="0" width="90%">
<tr> <td>ID</td> <td>代码</td> <td>用户?lt;/td> <td>姓名</td> </tr>
<%
javax.sql.RowSet empRS = (javax.sql.RowSet) empPage.getRowSet();
if (empRS!=null) while (empRS.next() ) {
%>
<tr>
<td><%= empRS.getString("EMP_ID")%></td>
<td><%= empRS.getString("EMP_CODE")%></td>
<td><%= empRS.getString("USER_NAME")%></td>
<td><%= empRS.getString("REAL_NAME")%></td>
</tr>
<%
}// end while
%>
<tr>
<%
//昄总页数和当前|(pageno)以及分页代码?
//此处doQuery为页面上提交查询动作的javascript函数名， pageno为标识当前页码的参数?
%>
<td colspan=4><%= empPage .getHTML("doQuery", "pageno")%></td>
</tr>
</table>
</form>
效果如图Q?/p>
因ؓ分页昄一般都会伴有查询条件和查询动作Q页面应已经有校验查询条件和提交查询的javascriptҎQ如上面的doQueryQ，所以RowSetPage.getHTML()生成的分代码在用户选择新页码时直接回调前面的处理提交查询的javascriptҎ。注意在昄查询l果的时候上ơ的查询条g也需要保持，?lt;input type=text name=gender size=1 value="<%=request.getParameter("gender")%>">。同时由于页码的参数名可以指定，因此也支持在同一面中有多个分页区?br /> 另一U分代码实现是生成每一늚URLQ将查询参数和页码作为QueryString附在URL后面。这U方法的~陷是在查询条g比较复杂旉以处理，q且需要指定处理查询动作的servletQ可能不适合某些定制的查询操作?br /> 如果对RowSetPage.getHTML()生成的默认分代码不满意可以~写自己的分处理代码，RowSetPage提供了很多getterҎ用于获取相关信息Q如当前늠、总页数?总记录数和当前记录数{）?br /> 在实际应用中可以分|询和昄做成jsp taglibQ?q一步简化JSP代码Q屏蔽Java Code?/p>
附：分页工具cȝ源代码， 有注释，应该很容易理解?/p>
1.Page.java
2.RowSetPage.java(RowSetPagel承Page)
3.PagedStatement.java
4.PagedStatementOracleImpl.java(PagedStatementOracleImpll承PagedStatement)
您可以Q意用这些源代码Q但必须保留author evan_zhao@hotmail.com字样
///////////////////////////////////
//
// Page.java
// author: evan_zhao@hotmail.com
//
///////////////////////////////////
package page;
import java.util.List;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
/**
* Title: 分页对象<br>
* Description: 用于包含数据及分信息的对象<br>
* PagecdC用于昄分页信息的基本方法，但未指定所含数据的cdQ?
* 可根据需要实C特定方式l织数据的子c，<br>
* 如RowSetPage以RowSet装数据QListPage以List装数据<br>
* Copyright: Copyright (c) 2002 <br>
* @author evan_zhao@hotmail.com <br>
* @version 1.0
*/
public class Page implements java.io.Serializable {
public static final Page EMPTY_PAGE = new Page();
public static final int DEFAULT_PAGE_SIZE = 20;
public static final int MAX_PAGE_SIZE = 9999;
private int myPageSize = DEFAULT_PAGE_SIZE;
private int start;
private int avaCount,totalSize;
private Object data;
private int currentPageno;
private int totalPageCount;
/**
* 默认构造方法，只构造空?
*/
protected Page(){
this.init(0,0,0,DEFAULT_PAGE_SIZE,new Object());
}
/**
* 分页数据初始ҎQ由子类调用
* @param start 本页数据在数据库中的起始位置
* @param avaCount 本页包含的数据条?
* @param totalSize 数据库中总记录条?
* @param pageSize 本页定w
* @param data 本页包含的数?
*/
protected void init(int start, int avaCount, int totalSize, int pageSize, Object data){
this.avaCount =avaCount;
this.myPageSize = pageSize;
this.start = start;
this.totalSize = totalSize;
this.data=data;
//System.out.println("avaCount:"+avaCount);
//System.out.println("totalSize:"+totalSize);
if (avaCount>totalSize) {
//throw new RuntimeException("记录条数大于L敎ͼQ?);
}
this.currentPageno = (start -1)/pageSize +1;
this.totalPageCount = (totalSize + pageSize -1) / pageSize;
if (totalSize==0 && avaCount==0){
this.currentPageno = 1;
this.totalPageCount = 1;
}
//System.out.println("Start Index to Page No: " + start + "-" + currentPageno);
}
public Object getData(){
return this.data;
}
/**
* 取本|据容量（本页能包含的记录敎ͼ
* @return 本页能包含的记录?
*/
public int getPageSize(){
return this.myPageSize;
}
/**
* 是否有下一?
* @return 是否有下一?
*/
public boolean hasNextPage() {
/*
if (avaCount==0 && totalSize==0){
return false;
}
return (start + avaCount -1) < totalSize;
*/
return (this.getCurrentPageNo()<this.getTotalPageCount());
}
/**
* 是否有上一?
* @return 是否有上一?
*/
public boolean hasPreviousPage() {
/*
return start > 1;
*/
return (this.getCurrentPageNo()>1);
}
/**
* 获取当前늬一条数据在数据库中的位|?
* @return
*/
public int getStart(){
return start;
}
/**
* 获取当前|后一条数据在数据库中的位|?
* @return
*/
public int getEnd(){
int end = this.getStart() + this.getSize() -1;
if (end<0) {
end = 0;
}
return end;
}
/**
* 获取上一늬一条数据在数据库中的位|?
* @return 记录对应的rownum
*/
public int getStartOfPreviousPage() {
return Math.max(start-myPageSize, 1);
}
/**
* 获取下一늬一条数据在数据库中的位|?
* @return 记录对应的rownum
*/
public int getStartOfNextPage() {
return start + avaCount;
}
/**
* 获取M늬一条数据在数据库中的位|，每页条数使用默认?
* @param pageNo 号
* @return 记录对应的rownum
*/
public static int getStartOfAnyPage(int pageNo){
return getStartOfAnyPage(pageNo, DEFAULT_PAGE_SIZE);
}
/**
* 获取M늬一条数据在数据库中的位|?
* @param pageNo 号
* @param pageSize 每页包含的记录数
* @return 记录对应的rownum
*/
public static int getStartOfAnyPage(int pageNo, int pageSize){
int startIndex = (pageNo-1) * pageSize + 1;
if ( startIndex < 1) startIndex = 1;
//System.out.println("Page No to Start Index: " + pageNo + "-" + startIndex);
return startIndex;
}
/**
* 取本包含的记录?
* @return 本页包含的记录数
*/
public int getSize() {
return avaCount;
}
/**
* 取数据库中包含的总记录数
* @return 数据库中包含的总记录数
*/
public int getTotalSize() {
return this.totalSize;
}
/**
* 取当前页?
* @return 当前늠
*/
public int getCurrentPageNo(){
return this.currentPageno;
}
/**
* 取总页?
* @return 总页?
*/
public int getTotalPageCount(){
return this.totalPageCount;
}
/**
*
* @param queryJSFunctionName 实现分页的JS脚本名字Q页码变动时会自动回调该Ҏ
* @param pageNoParamName 늠参数名称
* @return
*/
public String getHTML(String queryJSFunctionName, String pageNoParamName){
if (getTotalPageCount()<1){
return "<input type='hidden' name='"+pageNoParamName+"' value='1' >";
}
if (queryJSFunctionName == null || queryJSFunctionName.trim().length()<1) {
queryJSFunctionName = "gotoPage";
}
if (pageNoParamName == null || pageNoParamName.trim().length()<1){
pageNoParamName = "pageno";
}
String gotoPage = "_"+queryJSFunctionName;
StringBuffer html = new StringBuffer("\n");
html.append("<script language=\"Javascript1.2\">\n")
.append("function ").append(gotoPage).append("(pageNo){ \n")
.append( " var curPage=1; \n")
.append( " try{ curPage = document.all[\"")
.append(pageNoParamName).append("\"].value; \n")
.append( " document.all[\"").append(pageNoParamName)
.append("\"].value = pageNo; \n")
.append( " ").append(queryJSFunctionName).append("(pageNo); \n")
.append( " return true; \n")
.append( " }catch(e){ \n")
// .append( " try{ \n")
// .append( " document.forms[0].submit(); \n")
// .append( " }catch(e){ \n")
.append( " alert('未定义查询ҎQfunction ")
.append(queryJSFunctionName).append("()'); \n")
.append( " document.all[\"").append(pageNoParamName)
.append("\"].value = curPage; \n")
.append( " return false; \n")
// .append( " } \n")
.append( " } \n")
.append( "}")
.append( "</script> \n")
.append( "");
html.append( "<table border=0 cellspacing=0 cellpadding=0 align=center width=80%> \n")
.append( " <tr> \n")
.append( " <td align=left><br> \n");
html.append( " ? ).append( getTotalPageCount() ).append( "?)
.append( " [") .append(getStart()).append("..").append(getEnd())
.append("/").append(this.getTotalSize()).append("] \n")
.append( " </td> \n")
.append( " <td align=right> \n");
if (hasPreviousPage()){
html.append( "[<a href='javascript:").append(gotoPage)
.append("(") .append(getCurrentPageNo()-1)
.append( ")'>上一?lt;/a>] \n");
}
html.append( " W?)
.append( " <select name='")
.append(pageNoParamName).append("' onChange='javascript:")
.append(gotoPage).append("(this.value)'>\n");
String selected = "selected";
for(int i=1;i<=getTotalPageCount();i++){
if( i == getCurrentPageNo() )
selected = "selected";
else selected = "";
html.append( " <option value='").append(i).append("' ")
.append(selected).append(">").append(i).append("</option> \n");
}
if (getCurrentPageNo()>getTotalPageCount()){
html.append( " <option value='").append(getCurrentPageNo())
.append("' selected>").append(getCurrentPageNo())
.append("</option> \n");
}
html.append( " </select>?\n");
if (hasNextPage()){
html.append( " [<a href='javascript:").append(gotoPage)
.append("(").append((getCurrentPageNo()+1))
.append( ")'>下一?lt;/a>] \n");
}
html.append( "</td></tr></table> \n");
return html.toString();
}
}
///////////////////////////////////
//
// RowSetPage.java
// author: evan_zhao@hotmail.com
//
///////////////////////////////////
package page;
import javax.sql.RowSet;
/**
* <p>Title: RowSetPage</p>
* <p>Description: 使用RowSet装数据的分对?lt;/p>
* <p>Copyright: Copyright (c) 2003</p>
* @author evan_zhao@hotmail.com
* @version 1.0
*/
public class RowSetPage extends Page {
private javax.sql.RowSet rs;
/**
*I页
*/
public static final RowSetPage EMPTY_PAGE = new RowSetPage();
/**
*默认构造方法，创徏I页
*/
public RowSetPage(){
this(null, 0,0);
}
/**
*构造分对?
*@param crs 包含一|据的OracleCachedRowSet
*@param start 该页数据在数据库中的起始位置
*@param totalSize 数据库中包含的记录L
*/
public RowSetPage(RowSet crs, int start, int totalSize) {
this(crs,start,totalSize,Page.DEFAULT_PAGE_SIZE);
}
/**
*构造分对?
*@param crs 包含一|据的OracleCachedRowSet
*@param start 该页数据在数据库中的起始位置
*@param totalSize 数据库中包含的记录L
*@pageSize 本页能容U的记录?
*/
public RowSetPage(RowSet crs, int start, int totalSize, int pageSize) {
try{
int avaCount=0;
if (crs!=null) {
crs.beforeFirst();
if (crs.next()){
crs.last();
avaCount = crs.getRow();
}
crs.beforeFirst();
}
rs = crs;
super.init(start,avaCount,totalSize,pageSize,rs);
}catch(java.sql.SQLException sqle){
throw new RuntimeException(sqle.toString());
}
}
/**
*取分对象中的记录数?
*/
public javax.sql.RowSet getRowSet(){
return rs;
}
}
///////////////////////////////////
//
// PagedStatement.java
// author: evan_zhao@hotmail.com
//
///////////////////////////////////
package page;
import foo.DBUtil;
import java.math.BigDecimal;
import java.util.List;
import java.util.Iterator;
import java.util.Collections;
import java.sql.Connection;
import java.sql.SQLException;
import java.sql.ResultSet;
import java.sql.Statement;
import java.sql.PreparedStatement;
import java.sql.Timestamp;
import javax.sql.RowSet;
/**
* <p>Title: 分页查询</p>
* <p>Description: Ҏ查询语句和页码查询出当页数据</p>
* <p>Copyright: Copyright (c) 2002</p>
* @author evan_zhao@hotmail.com
* @version 1.0
*/
public abstract class PagedStatement {
public final static int MAX_PAGE_SIZE = Page.MAX_PAGE_SIZE;
protected String countSQL, querySQL;
protected int pageNo,pageSize,startIndex,totalCount;
protected javax.sql.RowSet rowSet;
protected RowSetPage rowSetPage;
private List boundParams;
/**
* 构造一查询出所有数据的PageStatement
* @param sql query sql
*/
public PagedStatement(String sql){
this(sql,1,MAX_PAGE_SIZE);
}
/**
* 构造一查询出当|据的PageStatement
* @param sql query sql
* @param pageNo 늠
*/
public PagedStatement(String sql, int pageNo){
this(sql, pageNo, Page.DEFAULT_PAGE_SIZE);
}
/**
* 构造一查询出当|据的PageStatementQƈ指定每页昄记录条数
* @param sql query sql
* @param pageNo 늠
* @param pageSize 每页定w
*/
public PagedStatement(String sql, int pageNo, int pageSize){
this.pageNo = pageNo;
this.pageSize = pageSize;
this.startIndex = Page.getStartOfAnyPage(pageNo, pageSize);
this.boundParams = Collections.synchronizedList(new java.util.LinkedList());
this.countSQL = "select count(*) from ( " + sql +") ";
this.querySQL = intiQuerySQL(sql, this.startIndex, pageSize);
}
/**
*生成查询一|据的sql语句
*@param sql 原查询语?
*@startIndex 开始记录位|?
*@size 需要获取的记录?
*/
protected abstract String intiQuerySQL(String sql, int startIndex, int size);
/**
*使用l出的对象设|指定参数的?
*@param index W一个参Cؓ1Q第二个?Q。。?
*@param obj 包含参数值的对象
*/
public void setObject(int index, Object obj) throws SQLException{
BoundParam bp = new BoundParam(index, obj);
boundParams.remove(bp);
boundParams.add( bp);
}
/**
*使用l出的对象设|指定参数的?
*@param index W一个参Cؓ1Q第二个?Q。。?
*@param obj 包含参数值的对象
*@param targetSqlType 参数的数据库cd
*/
public void setObject(int index, Object obj, int targetSqlType) throws SQLException{
BoundParam bp = new BoundParam(index, obj, targetSqlType);
boundParams.remove(bp);
boundParams.add(bp );
}
/**
*使用l出的对象设|指定参数的?
*@param index W一个参Cؓ1Q第二个?Q。。?
*@param obj 包含参数值的对象
*@param targetSqlType 参数的数据库cd(帔R定义在java.sql.Types?
*@param scale _ֺQ小数点后的位数
* Q只对targetSqlType是Types.NUMBER或Types.DECIMAL有效Q其它类型则忽略Q?
*/
public void setObject(int index, Object obj, int targetSqlType, int scale) throws SQLException{
BoundParam bp = new BoundParam(index, obj, targetSqlType, scale) ;
boundParams.remove(bp);
boundParams.add(bp);
}
/**
*使用l出的字W串讄指定参数的?
*@param index W一个参Cؓ1Q第二个?Q。。?
*@param str 包含参数值的字符?
*/
public void setString(int index, String str)throws SQLException{
BoundParam bp = new BoundParam(index, str) ;
boundParams.remove(bp);
boundParams.add(bp);
}
/**
*使用l出的字W串讄指定参数的?
*@param index W一个参Cؓ1Q第二个?Q。。?
*@param timestamp 包含参数值的旉?
*/
public void setTimestamp(int index, Timestamp timestamp)throws SQLException{
BoundParam bp = new BoundParam(index, timestamp) ;
boundParams.remove(bp);
boundParams.add( bp );
}
/**
*使用l出的整数设|指定参数的?
*@param index W一个参Cؓ1Q第二个?Q。。?
*@param value 包含参数值的整数
*/
public void setInt(int index, int value)throws SQLException{
BoundParam bp = new BoundParam(index, new Integer(value)) ;
boundParams.remove(bp);
boundParams.add( bp );
}
/**
*使用l出的长整数讄指定参数的?
*@param index W一个参Cؓ1Q第二个?Q。。?
*@param value 包含参数值的长整?
*/
public void setLong(int index, long value)throws SQLException{
BoundParam bp = new BoundParam(index, new Long(value)) ;
boundParams.remove(bp);
boundParams.add( bp );
}
/**
*使用l出的双_ֺ点数设|指定参数的?
*@param index W一个参Cؓ1Q第二个?Q。。?
*@param value 包含参数值的双精度QҎ
*/
public void setDouble(int index, double value)throws SQLException{
BoundParam bp = new BoundParam(index, new Double(value)) ;
boundParams.remove(bp);
boundParams.add( bp);
}
/**
*使用l出的BigDecimal讄指定参数的?
*@param index W一个参Cؓ1Q第二个?Q。。?
*@param bd 包含参数值的BigDecimal
*/
public void setBigDecimal(int index, BigDecimal bd)throws SQLException{
BoundParam bp = new BoundParam(index, bd ) ;
boundParams.remove(bp);
boundParams.add( bp);
}
private void setParams(PreparedStatement pst) throws SQLException{
if (pst==null || this.boundParams==null || this.boundParams.size()==0 ) return ;
BoundParam param;
for (Iterator itr = this.boundParams.iterator();itr.hasNext();){
param = (BoundParam) itr.next();
if (param==null) continue;
if (param.sqlType == java.sql.Types.OTHER){
pst.setObject(param.index, param.value);
}else{
pst.setObject(param.index, param.value, param.sqlType, param.scale);
}
}
}
/**
* 执行查询取得一|据，执行l束后关闭数据库q接
* @return RowSetPage
* @throws SQLException
*/
public RowSetPage executeQuery() throws SQLException{
System.out.println("executeQueryUsingPreparedStatement");
Connection conn = DBUtil.getConnection();
PreparedStatement pst = null;
ResultSet rs = null;
try{
pst = conn.prepareStatement(this.countSQL);
setParams(pst);
rs =pst.executeQuery();
if (rs.next()){
totalCount = rs.getInt(1);
} else {
totalCount = 0;
}
rs.close();
pst.close();
if (totalCount < 1 ) return RowSetPage.EMPTY_PAGE;
pst = conn.prepareStatement(this.querySQL);
System.out.println(querySQL);
pst.setFetchSize(this.pageSize);
setParams(pst);
rs =pst.executeQuery();
//rs.setFetchSize(pageSize);
this.rowSet = populate(rs);
rs.close();
rs = null;
pst.close();
pst = null;
this.rowSetPage = new RowSetPage(this.rowSet,startIndex,totalCount,pageSize);
return this.rowSetPage;
}catch(SQLException sqle){
//System.out.println("executeQuery SQLException");
sqle.printStackTrace();
throw sqle;
}catch(Exception e){
e.printStackTrace();
throw new RuntimeException(e.toString());
}finally{
//System.out.println("executeQuery finally");
DBUtil.close(rs, pst, conn);
}
}
/**
*ResultSet数据填充qCachedRowSet
*/
protected abstract RowSet populate(ResultSet rs) throws SQLException;
/**
*取封装成RowSet查询l果
*@return RowSet
*/
public javax.sql.RowSet getRowSet(){
return this.rowSet;
}
/**
*取封装成RowSetPage的查询结?
*@return RowSetPage
*/
public RowSetPage getRowSetPage() {
return this.rowSetPage;
}
/**
*关闭数据库连?
*/
public void close(){
//因ؓ数据库连接在查询l束或发生异常时卛_闭，此处不做M事情
//留待扩充?
}
private class BoundParam {
int index;
Object value;
int sqlType;
int scale;
public BoundParam(int index, Object value) {
this(index, value, java.sql.Types.OTHER);
}
public BoundParam(int index, Object value, int sqlType) {
this(index, value, sqlType, 0);
}
public BoundParam(int index, Object value, int sqlType, int scale) {
this.index = index;
this.value = value;
this.sqlType = sqlType;
this.scale = scale;
}
public boolean equals(Object obj){
if (obj!=null && this.getClass().isInstance(obj)){
BoundParam bp = (BoundParam)obj;
if (this.index==bp.index) return true;
}
return false;
}
}
}
///////////////////////////////////
//
// PagedStatementOracleImpl.java
// author: evan_zhao@hotmail.com
//
///////////////////////////////////
package page;
import java.sql.ResultSet;
import java.sql.SQLException;
import javax.sql.RowSet;
import oracle.jdbc.rowset.OracleCachedRowSet;
/**
* <p>Title: 分页查询Oracle数据库实?lt;/p>
* <p>Copyright: Copyright (c) 2002</p>
* @author evan_zhao@hotmail.com
* @version 1.0
*/
public class PagedStatementOracleImpl extends PagedStatement {
/**
* 构造一查询出所有数据的PageStatement
* @param sql query sql
*/
public PagedStatementOracleImpl(String sql){
super(sql);
}
/**
* 构造一查询出当|据的PageStatement
* @param sql query sql
* @param pageNo 늠
*/
public PagedStatementOracleImpl(String sql, int pageNo){
super(sql, pageNo);
}
/**
* 构造一查询出当|据的PageStatementQƈ指定每页昄记录条数
* @param sql query sql
* @param pageNo 늠
* @param pageSize 每页定w
*/
public PagedStatementOracleImpl(String sql, int pageNo, int pageSize){
super(sql, pageNo, pageSize);
}
/**
*生成查询一|据的sql语句
*@param sql 原查询语?
*@startIndex 开始记录位|?
*@size 需要获取的记录?
*/
protected String intiQuerySQL(String sql, int startIndex, int size){
StringBuffer querySQL = new StringBuffer();
if (size != super.MAX_PAGE_SIZE) {
querySQL.append("select * from (select my_table.*,rownum as my_rownum from(")
.append( sql)
.append(") my_table where rownum<").append(startIndex + size)
.append(") where my_rownum>=").append(startIndex);
} else {
querySQL.append("select * from (select my_table.*,rownum as my_rownum from(")
.append(sql)
.append(") my_table ")
.append(") where my_rownum>=").append(startIndex);
}
return querySQL.toString();
}
/**
*ResultSet数据填充qCachedRowSet
*/
protected RowSet populate(ResultSet rs) throws SQLException{
OracleCachedRowSet ocrs = new OracleCachedRowSet();
ocrs.populate(rs);
return ocrs;
}
}
]]>