JSP自定义分页标签TAG全过程

package com.lss.common.tag; 

import java.io.ioexception; 

import javax.servlet.jsp.jspexception; 
import javax.servlet.jsp.jspwriter; 
import javax.servlet.jsp.tagext.tagsupport; 

import com.lss.common.page.htmlpage; 
import com.lss.common.page.page; 
import com.lss.common.page.variablepage; 

/** 
* 分页处理标签 
* 
* @description 
* @date 2012-3-11下午09:08:46 
*/ 
public class pagetag extends tagsupport { 
private int pageno; 
private int pagesize = 10; 
private int totalsum; 
private int showpage = 10; 
private string url; 

public int getpageno() { 
return pageno; 
} 

public void setpageno(int pageno) { 
this.pageno = pageno; 
} 

public int getpagesize() { 
return pagesize; 
} 

public void setpagesize(int pagesize) { 
this.pagesize = pagesize; 
} 

public int gettotalsum() { 
return totalsum; 
} 

public void settotalsum(int totalsum) { 
this.totalsum = totalsum; 
} 

public int getshowpage() { 
return showpage; 
} 

public void setshowpage(int showpage) { 
this.showpage = showpage; 
} 

public string geturl() { 
return url; 
} 

public void seturl(string url) { 
this.url = url; 
} 

@override 
public int doendtag() throws jspexception { 
if (pagesize == 0) { 
return tagsupport.skip_page;// 不显示分页 
} else if (pagesize > totalsum) { 
return tagsupport.skip_body;// 不显示分页 
} 
jspwriter out = pagecontext.getout(); 
try { 
if (url.indexof(";jsessionid=") == -1) { 
if (url.indexof("?") == -1) { 
url += ";jsessionid=" + pagecontext.getsession().getid() + "?pageno="; 
} else { 
url = url.replacefirst("\\?", ";jsessionid=" + pagecontext.getsession().getid() + "?"); 
if (url.indexof("pageno=") == -1) { 
url += "&pageno="; 
} 
} 
} 
url = pagecontext.getservletcontext().getcontextpath() + url; 
variablepage variablepage = new variablepage(pageno, totalsum, pagesize, url); 
variablepage.setshowpagenum(showpage); 
page page = new htmlpage(variablepage); 
out.print(page.getfirstno() + " " + page.getbackpagenum() + " " + page.pagination() + " " + page.getnextpagenum() + " " + page.getlastno()); 
} catch (ioexception ex) { 
ex.printstacktrace(); 
} 
return super.doendtag(); 
} 

@override 
public void release() { 
url = null; 
pageno = 0; 
totalsum = 0; 
pagesize = 10; 
super.release(); 
} 

private static final long serialversionuid = -2642907859641024483l; 
}

/** 
* html 分页类 
* 
* @description 
* @date 2012-3-11下午10:33:14 
*/ 
public class htmlpage extends page { 
public htmlpage(variablepage variablepage) { 
super(variablepage); 
} 

public string pagination() { 
string printno = ""; 
// 如果已分页；并且页数小于等于要显示的页数 
if (variablepage.totalpage > 1 && variablepage.totalpage <= variablepage.showpagenum) { 
return displayall(); 
// 如果分页数：大于显示的页码数 
} else if (variablepage.totalpage > 1 && variablepage.totalpage > variablepage.showpagenum) { 
if (variablepage.pageno == 1) {// 当前页等于第一页 
return fromfirstpageprint(); 
} else if (variablepage.pageno == variablepage.totalpage) {// 当前页等于最后一页 
return fromlastpageprint(); 
} else {// 如果当前页：即不是首页也不是尾页 
if (variablepage.showpagenum % 2 == 0) {// 可以平分页码 
int print$no = variablepage.showpagenum / 2; 
if (variablepage.pageno >= print$no) { 
int index$no = variablepage.pageno - print$no; 
if (variablepage.pageno + print$no >= variablepage.totalpage) { 
return fromlastpageprint(); 
} else { 
if (index$no == 0) 
index$no = 1; 
for (int i = index$no; i < (variablepage.showpagenum + index$no); i++) { 
if (i == variablepage.pageno) {// 如果是当前页:不添加连接url 
printno += (i + variablepage.split); 
} else { 
printno += (builda(variablepage, i) + variablepage.split); 
} 
} 
} 
} else { 
return fromfirstpageprint(); 
} 
} else {// 打印页数不是偶数时： 
int print$no = variablepage.showpagenum / 2 + 1; 
if (variablepage.pageno >= print$no && variablepage.pageno + print$no < variablepage.totalpage) { 
int index$no = variablepage.pageno - print$no + 1; 
for (int i = index$no; i < variablepage.showpagenum + index$no; i++) { 
if (i == variablepage.pageno) {// 如果是当前页:不添加连接url 
printno += (i + variablepage.split); 
} else { 
printno += (builda(variablepage, i) + variablepage.split); 
} 
} 
} else if (variablepage.pageno <= print$no) {// 从第一页开始 
return fromfirstpageprint(); 
} else { 
return fromlastpageprint(); 
} 
} 
} 
return (printno); 
} else { 
return "1"; 
} 
} 

public string getbackpagenum() { 
if (variablepage.pageno <= 1) { 
return buildspan("上一页", variablepage); 
} else { 
return builda("上一页", (variablepage.url + (variablepage.pageno - 1))); 
} 
} 

public string getnextpagenum() { 
if (variablepage.pageno >= variablepage.totalpage) { 
return buildspan("下一页", variablepage); 
} else { 
return builda("下一页", variablepage.url + (variablepage.pageno + 1)); 
} 
} 

public string buildspan(string text, variablepage variablepage) { 
return "<span style=\"color:gray;\">" + text + "</span>"; 
} 

public string builda(string text, string url) { 
return "<a href=\"" + url + "\">" + text + "</a>"; 
} 

public string builda(variablepage variablepage, int num) { 
return ("<a href=\"" + variablepage.url + num + "\">" + num + "</a>"); 
} 
}

public abstract class page { 
protected variablepage variablepage; 

public page(variablepage variablepage) { 
this.variablepage = variablepage; 
calculatetotalpage(); 
} 

public int getstartindex() { 
return (getvalidpagenum() - 1) * variablepage.pagesize; 
} 

public string getbackpagenum() { 
if (variablepage.pageno <= 1) { 
return buildspan("上一页", variablepage); 
} else { 
return builda("上一页", variablepage.geturl() + (variablepage.pageno - 1)); 
} 
} 

public string getnextpagenum() { 
if (variablepage.pageno >= variablepage.totalpage) { 
return buildspan("下一页", variablepage); 
} else { 
return builda("下一页", variablepage.geturl() + (variablepage.pageno + 1)); 
} 
} 

/** 
* 计算总页数 
*/ 
private void calculatetotalpage() { 
if (variablepage.totalsum % variablepage.pagesize == 0) { 
variablepage.totalpage = variablepage.totalsum / variablepage.pagesize; 
} else { 
variablepage.totalpage = variablepage.totalsum / variablepage.pagesize + 1; 
} 
if (variablepage.totalpage < variablepage.pageno) { 
variablepage.pageno = variablepage.totalpage; 
} else if (variablepage.pageno < 1) { 
variablepage.pageno = 1; 
} 
} 

protected string displayall() { 
stringbuilder sbuilder = new stringbuilder(10); 
sbuilder.append(variablepage.split); 
for (int i = 1; i <= variablepage.totalpage; i++) { 
if (i == variablepage.pageno) { 
sbuilder.append(i + variablepage.split); 
} else { 
sbuilder.append(builda(variablepage, i) + variablepage.split); 
} 
} 
return sbuilder.tostring(); 
} 

/** 
* 抽象出分页方法 
* 
* @return 
*/ 
public abstract string pagination(); 

/** 
* 实现从第一页开始打印 
* 
* @return 
*/ 
protected final string fromfirstpageprint() { 
stringbuffer buffer = new stringbuffer(100); 
for (int i = 1; i <= variablepage.showpagenum; i++) { 
if (i == variablepage.pageno) {// 如果是当前页:不添加连接url 
buffer.append(i + variablepage.split); 
} else { 
buffer.append(builda(variablepage, i) + variablepage.split); 
} 
} 
return buffer.tostring(); 
} 

/** 
* 实现从最后一页开始打印 
* 
* @return 
*/ 
protected final string fromlastpageprint() { 
stringbuffer buffer = new stringbuffer(100); 
int startpage = variablepage.totalpage - (variablepage.showpagenum - 1); 
for (int i = startpage; i <= variablepage.totalpage; i++) { 
if (i == variablepage.pageno) {// 如果是当前页:不添加连接url 
buffer.append(i + variablepage.split); 
} else { 
buffer.append(builda(variablepage, i) + variablepage.split); 
} 
} 
return buffer.tostring(); 
} 

public string getfirstno() { 
if (isexistspagination()) { 
return builda("首页", variablepage.url + 1); 
} else { 
return buildspan("首页", variablepage); 
} 
} 

/** 
* 判断是否存在分页 
* 
* @return 
*/ 
private boolean isexistspagination() { 
if (variablepage.totalsum > 1 && variablepage.totalpage > 1) { 
return true; 
} 
return false; 
} 

public string getlastno() { 
if (isexistspagination()) { 
return builda("尾页", variablepage.url + variablepage.totalpage); 
} else { 
return buildspan("尾页", variablepage); 
} 
} 

protected int getvalidpagenum() { 
if (variablepage.totalpage < variablepage.pageno) { 
return variablepage.pageno = variablepage.totalpage; 
} else if (variablepage.pageno < 1) { 
return variablepage.pageno = 1; 
} else { 
return variablepage.pageno; 
} 
} 

public variablepage getpagecontant() { 
return this.variablepage; 
} 

public abstract string buildspan(string text, variablepage variablepage); 

public abstract string builda(string text, string url); 

public abstract string builda(variablepage variablepage, int num); 

public string printmodifypagesize(int pagesize){ 
stringbuilder builder=new stringbuilder(100); 
builder.append("每页<input type='text' id='pagesize' style='width:20px' maxlength='2' name='pagesize'"); 
if(pagesize>0){ 
builder.append(" value='"+pagesize+"' "); 
} 
builder.append("/>条"); 
return builder.tostring(); 
} 
}

/** 
* 分页基础变量 
* 
* @description 
* @date 2012-3-11下午10:34:00 
*/ 
public class simplevariable { 
/** 
* 显示页码 
*/ 
protected int showpagenum = 10; 
/** 
* 连接url 
*/ 
protected string url = null; 
/** 
* 当前页码 
*/ 
protected int pageno = 1; 
/** 
* 总页码 
*/ 
protected int totalpage = 1; 
/** 
* 总条数 
*/ 
protected int totalsum = 0; 
/** 
* 每页显示条数 
*/ 
protected int pagesize = 10; 

public string geturl() { 
return url; 
} 

public void seturl(string url) { 
this.url = url; 
} 

public int gettotalpage() { 
return totalpage; 
} 

public void settotalpage(int totalpage) { 
this.totalpage = totalpage; 
} 

public int gettotalsum() { 
return totalsum; 
} 

public void settotalsum(int totalsum) { 
this.totalsum = totalsum; 
} 

public int getpagesize() { 
return pagesize; 
} 

public void setpagesize(int pagesize) { 
this.pagesize = pagesize; 
} 

public int getshowpagenum() { 
return showpagenum; 
} 

public void setshowpagenum(int showpagenum) { 
this.showpagenum = showpagenum; 
} 

public int getpageno() { 
return pageno; 
} 

public void setpageno(int pageno) { 
this.pageno = pageno; 
} 
} 

/** 
* 分页变量 
* 
* @description 
* @date 2012-3-11下午10:34:08 
*/ 
public class variablepage extends simplevariable { 
protected string split = " "; 
protected string style = "class='page'"; 

public variablepage(int pageno, int totalsum, int pagesize, string url) { 
pageno = pageno < 1 ? 1 : pageno; 
super.pageno = pageno; 
this.totalsum = totalsum; 
this.url = url; 
this.pagesize = pagesize; 
} 

public variablepage(int pagenum, int totalsum, string url) { 
pagenum = pagenum < 1 ? 1 : pagenum; 
super.pageno = pagenum; 
this.totalsum = totalsum; 
this.url = url; 
} 

public string getsplit() { 
return split; 
} 

public void setsplit(string split) { 
this.split = split; 
} 

}

<%@taglib uri="http://www.kevin.com/taglibs/page" prefix="page" %>

<page:htmlpage pageno="${pageno}" url="your_url" totalsum="${totalsum}" showpage="10" pagesize="12"/>