小编给大家分享一下Oracle中Java分页功能有哪些，相信大部分人都还不怎么了解，因此分享这篇文章给大家参考一下，希望大家阅读完这篇文章后大有收获，下面让我们一起去了解一下吧！
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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{ private List list; private int pageNo; private int pageSize; private int totalNum; private int totalPage; public List getList() { return list; } public void setList(List 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 pagination = userInfoManage.userBasicSearch(u,
pageNo, pageSize);
List userList = pagination.getList();
// 3.封装返回结果
StringBuffer resultXML = new StringBuffer();
try {
resultXML.append("/n");
resultXML.append("/n");
for (Iterator iterator = userList.iterator(); iterator
.hasNext();) {
UserInfo userInfo = iterator.next();
resultXML.append("/n");
resultXML.append("/t" + userInfo.getId() + " /n");
resultXML.append("/t" + userInfo.getTruename()
+ "/n");
resultXML.append("/t" + userInfo.getSex() + " /n");
resultXML.append("/t" + userInfo.getHome() + " /n");
resultXML.append(" /n");
}
resultXML.append("/n");
resultXML.append("/t" + pagination.getTotalPage()
+ " /n");
resultXML.append("/t" + pagination.getFirstPage()
+ " /n");
resultXML.append("/t" + pagination.getLastPage() + " /n");
resultXML.append("/t" + pagination.getPageNo()
+ " /n");
resultXML.append(" /n");
resultXML.append(" /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 userBasicSearch(UserInfo u, int pageNo,
int pageSize) throws Exception {
Connection connection = null;
PageModel pagination = new PageModel();
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 getUserList(UserInfo userInfo, int pageNo,
int pageSize) throws Exception {
PreparedStatement pstmt = null;
ResultSet rs = null;
List 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();
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 threadLocal = new ThreadLocal();
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。
以上是“Oracle中Java分页功能有哪些”这篇文章的所有内容，感谢各位的阅读！相信大家都有了一定的了解，希望分享的内容对大家有所帮助，如果还想学习更多知识，欢迎关注创新互联行业资讯频道！
