就如平时我们很在分页中看到的，分页的时候返回的不仅包括查询的结果集(list)，而且还包括总的页数(pagenum)、当前第几页(pageno)等等信息，所以我们封装一个查询结果pagemodel类，代码如下：
package com.bjpowernode.test;
import java.util.list;
public class pagemodel<e> {
private list<e> list;
private int pageno;
private int pagesize;
private int totalnum;
private int totalpage;
public list<e> getlist() {
return list;
}
public void setlist(list<e> list) {
this.list = list;
}
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 gettotalnum() {
return totalnum;
}
public void settotalnum(int totalnum) {
this.totalnum = totalnum;
settotalpage((gettotalnum() % pagesize) == 0 ? (gettotalnum() / pagesize)
: (gettotalnum() / pagesize + 1));
}
public int gettotalpage() {
return totalpage;
}
public void settotalpage(int totalpage) {
this.totalpage = totalpage;
}
// 获取第一页
public int getfirstpage() {
return 1;
}
// 获取最后页
public int getlastpage() {
return totalpage;
}
// 获取前页
public int getprepage() {
if (pageno > 1)
return pageno - 1;
return 1;
}
// 获取后页
public int getbackpage() {
if (pageno < totalpage)
return pageno + 1;
return totalpage;
}
// 判断'首页'及‘前页'是否可用
public string ispreable() {
if (pageno == 1)
return "disabled";
return "";
}
// 判断'尾页'及‘下页'是否可用
public string isbackable() {
if (pageno == totalpage)
return "disabled";
return "";
}
}
其中使用泛型是为了能使的该分页类能进行重用，比如在查询用户时可以封装user对象、在查询财务中的流向单时可以封装流向单flowcard类。
我们以查询用户为例，用户选择查询条件，首先调用servlet获取查询参数，然后请求业务逻辑层取得分页封装结果类。业务逻辑调用dao层取得结果集、取得中记录数封装成分页类。最后servlet将结果设置到jsp页面显示。
首先来讲解servlet，代码如下：
package com.bjpowernode.test;
import java.io.*;
import java.util.*;
import javax.servlet.servletconfig;
import javax.servlet.servletexception;
import javax.servlet.http.httpservlet;
import javax.servlet.http.httpservletrequest;
import javax.servlet.http.httpservletresponse;
import kane.userinfo;
import kane.userinfomanage;
import kane.pagemodel;
public class userbasicsearchservlet extends httpservlet {
private static final long serialversionuid = 1l;
private int pagesize = 0;
@override
public void init(servletconfig config) throws servletexception {
pagesize = integer.parseint(config.getinitparameter("pagesize"));
}
@override
protected void doget(httpservletrequest req, httpservletresponse resp)
throws servletexception, ioexception {
dopost(req, resp);
}
@override
protected void dopost(httpservletrequest req, httpservletresponse resp)
throws servletexception, ioexception {
// 1.取得页面参数并构造参数对象
int pageno = integer.parseint(req.getparameter("pageno"));
string sex = req.getparameter("gender");
string home = req.getparameter("newlocation");
string colleage = req.getparameter("colleage");
string comingyear = req.getparameter("comingyear");
userinfo u = new userinfo();
u.setsex(sex);
u.sethome(home);
u.setcolleage(colleage);
u.setcy(comingyear);
// 2.调用业务逻辑取得结果集
userinfomanage userinfomanage = new userinfomanage();
pagemodel<userinfo> pagination = userinfomanage.userbasicsearch(u,
pageno, pagesize);
list<userinfo> userlist = pagination.getlist();
// 3.封装返回结果
stringbuffer resultxml = new stringbuffer();
try {
resultxml.append("<?xml version='1.0' encoding='gb18030'?>/n");
resultxml.append("<root>/n");
for (iterator<userinfo> iterator = userlist.iterator(); iterator
.hasnext();) {
userinfo userinfo = iterator.next();
resultxml.append("<data>/n");
resultxml.append("/t<id>" + userinfo.getid() + "</id>/n");
resultxml.append("/t<truename>" + userinfo.gettruename()
+ "</ truename >/n");
resultxml.append("/t<sex>" + userinfo.getsex() + "</sex>/n");
resultxml.append("/t<home>" + userinfo.gethome() + "</home>/n");
resultxml.append("</data>/n");
}
resultxml.append("<pagination>/n");
resultxml.append("/t<total>" + pagination.gettotalpage()
+ "</total>/n");
resultxml.append("/t<start>" + pagination.getfirstpage()
+ "</start>/n");
resultxml.append("/t<end>" + pagination.getlastpage() + "</end>/n");
resultxml.append("/t<pageno>" + pagination.getpageno()
+ "</pageno>/n");
resultxml.append("</pagination>/n");
resultxml.append("</root>/n");
} catch (exception e) {
e.printstacktrace();
}
writeresponse(req, resp, resultxml.tostring());
}
public void writeresponse(httpservletrequest request,
httpservletresponse response, string result) throws ioexception {
response.setcontenttype("text/xml");
response.setheader("cache-control", "no-cache");
response.setheader("content-type", "text/xml; charset=gb18030");
printwriter pw = response.getwriter();
pw.write(result);
pw.close();
}
}
其中user对象代码如下：
package com.bjpowernode.test;
import java.util.date;
public class userinfo {
private int id;
private string username;
private string password;
private string truename;
private string sex;
private date birthday;
private string home;
private string colleage;
private string comingyear;
public int getid() {
return id;
}
public void setid(int id) {
this.id = id;
}
public string getusername() {
return username;
}
public void setusername(string username) {
this.username = username;
}
public string getpassword() {
return password;
}
public void setpassword(string password) {
this.password = password;
}
public string gettruename() {
return truename;
}
public void settruename(string truename) {
this.truename = truename;
}
public string getsex() {
return sex;
}
public void setsex(string sex) {
this.sex = sex;
}
public date getbirthday() {
return birthday;
}
public void setbirthday(date birthday) {
this.birthday = birthday;
}
public string gethome() {
return home;
}
public void sethome(string home) {
this.home = home;
}
public string getcolleage() {
return colleage;
}
public void setcolleage(string colleage) {
this.colleage = colleage;
}
public string getcy() {
return comingyear;
}
public void setcy(string cy) {
this. comingyear= cy;
}
}
接着是业务逻辑层代码，代码如下：
package com.bjpowernode.test;
import java.sql.connection;
import kane.dbutility;
import kane.pagemodel;
public class userinfomanage {
private userinfodao userinfodao = null;
public userinfomanage () {
userinfodao = new userinfodao();
}
public pagemodel<userinfo> userbasicsearch(userinfo u, int pageno,
int pagesize) throws exception {
connection connection = null;
pagemodel<userinfo> pagination = new pagemodel<userinfo>();
try {
connection = dbutility.getconnection();
dbutility.setautocommit(connection, false);
pagination.setlist(userinfodao.getuserlist(u, pageno, pagesize));
pagination.setpageno(pageno);
pagination.setpagesize(pagesize);
pagination.settotalnum(userinfodao.gettotalnum(u));
dbutility.commit(connection);
} catch (exception e) {
dbutility.rollback(connection);
e.printstacktrace();
throw new exception();
} finally {
dbutility.closeconnection();
}
return pagination;
}
}
其中dbutility为数据库的连接封装类。
最后是dao层代码实现，代码如下：
package com.bjpowernode.test;
import java.sql.connection;
import java.sql.preparedstatement;
import java.sql.resultset;
import java.sql.sqlexception;
import java.util.arraylist;
import java.util.list;
import kane.userinfo;
import kane.dbutility;
public class userinfodao {
public list<userinfo> getuserlist(userinfo userinfo, int pageno,
int pagesize) throws exception {
preparedstatement pstmt = null;
resultset rs = null;
list<userinfo> userlist = null;
try {
string sql = "select * from(select rownum num,u.* from(select * from user_info where sex = ? and home like '"
+ userinfo.gethome()
+ "%"
+ "' and colleage like '"
+ userinfo.getcolleage()
+ "%"
+ "' and comingyear like '"
+ userinfo.getcy()
+ "%"
+ "' order by id) u where rownum<=?) where num>=?";
userlist = new arraylist<userinfo>();
connection conn = dbutility.getconnection();
pstmt = conn.preparestatement(sql);
pstmt.setstring(1, userinfo.getsex());
pstmt.setint(2, pageno * pagesize);
pstmt.setint(3, (pageno - 1) * pagesize + 1);
rs = pstmt.executequery();
while (rs.next()) {
userinfo user = new userinfo();
user.setid(rs.getint("id"));
user.settruename(rs.getstring("truename"));
user.setsex(rs.getstring("sex"));
user.sethome(rs.getstring("home"));
userlist.add(user);
}
} catch (sqlexception e) {
e.printstacktrace();
throw new exception(e);
} finally {
dbutility.closeresultset(rs);
dbutility.closepreparedstatement(pstmt);
}
return userlist;
}
public int gettotalnum(userinfo userinfo) throws exception {
preparedstatement pstmt = null;
resultset rs = null;
int count = 0;
try {
string sql = "select count(*) from user_info where sex=? and home like '"
+ userinfo.gethome()
+ "%"
+ "' and colleage like '"
+ userinfo.getcolleage()
+ "%"
+ "' and comingyear like '"
+ userinfo.getcy()+ "%" + "'";
connection conn = dbutility.getconnection();
pstmt = conn.preparestatement(sql);
pstmt.setstring(1, userinfo.getsex());
rs = pstmt.executequery();
if (rs.next()) {
count = rs.getint(1);
}
} catch (sqlexception e) {
e.printstacktrace();
throw new exception(e);
} finally {
dbutility.closeresultset(rs);
dbutility.closepreparedstatement(pstmt);
}
return count;
}
}
最后就是servlet将得到的结果返回给jsp页面显示出来。
注：其中dbutility代码是封装数据库连接操作的代码，如下：
1.package com.bjpowernode.test;
import java.sql.connection;
import java.sql.drivermanager;
import java.sql.preparedstatement;
import java.sql.resultset;
import java.sql.sqlexception;
public class dbutility {
private static threadlocal<connection> threadlocal = new threadlocal<connection>();
public static connection getconnection() {
connection conn = null;
conn = threadlocal.get();
if (conn == null) {
try {
class.forname("oracle.jdbc.driver.oracledriver");
conn = drivermanager.getconnection(
"jdbc:oracle:thin:@localhost:1521:oracle", "admin",
"admin");
threadlocal.set(conn);
} catch (classnotfoundexception e) {
e.printstacktrace();
} catch (sqlexception e) {
e.printstacktrace();
}
}
return conn;
}
// 封装设置connection自动提交
public static void setautocommit(connection conn, boolean flag) {
try {
conn.setautocommit(flag);
} catch (sqlexception e) {
e.printstacktrace();
}
}
// 设置事务提交
public static void commit(connection conn) {
try {
conn.commit();
} catch (sqlexception e) {
e.printstacktrace();
}
}
// 封装设置connection回滚
public static void rollback(connection conn) {
try {
conn.rollback();
} catch (sqlexception e) {
e.printstacktrace();
}
}
// 封装关闭connection、preparedstatement、resultset的函数
public static void closeconnection() {
connection conn = threadlocal.get();
try {
if (conn != null) {
conn.close();
conn = null;
threadlocal.remove();
}
} catch (sqlexception e) {
e.printstacktrace();
}
}
public static void closepreparedstatement(preparedstatement pstmt) {
try {
if (pstmt != null) {
pstmt.close();
pstmt = null;
}
} catch (sqlexception e) {
e.printstacktrace();
}
}
public static void closeresultset(resultset rs) {
try {
if (rs != null) {
rs.close();
rs = null;
}
} catch (sqlexception e) {
e.printstacktrace();
}
}
}
使用threadlocal是为了保证事务的一致，使得同一个线程的所有数据库操作使用同一个connection。
到此一个简单的代码实现就完成了。
总结
以上所述是www.887551.com给大家介绍的oracle下的java分页功能，希望对大家有所帮助