s,ervlet分页代码示例

2019-11-02 14:52:49

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本文介绍了servlet分页代码实现，采用Oracle数据库，获取SCOTT用户EMP表中的数据，分页实现步骤看下面代码

1.首先创建一个对象 UserData，用以保存从数据库中获取的数据。代码如下:package com.tool; import java.math.BigDecimal;import java.util.Date; /** * Created by lx_sunwei on 14-1-6. */public class UserData { /** * EMP表中的数据属性 */ private String ename; private String job; private BigDecimal empno; private BigDecimal mgr; private Date hireDate; private BigDecimal sal; private BigDecimal comm; private BigDecimal deptno; public BigDecimal getEmpno() { return empno; } public void setEmpno(BigDecimal empno) { this.empno = empno; } public BigDecimal getMgr() { return mgr; } public void setMgr(BigDecimal mgr) { this.mgr = mgr; } public Date getHireDate() { return hireDate; } public void setHireDate(Date hireDate) { this.hireDate = hireDate; } public BigDecimal getSal() { return sal; } public void setSal(BigDecimal sal) { this.sal = sal; } public BigDecimal getComm() { return comm; } public void setComm(BigDecimal comm) { this.comm = comm; } public BigDecimal getDeptno() { return deptno; } public void setDeptno(BigDecimal deptno) { this.deptno = deptno; } public String getEname() { return ename; } public void setEname(String ename) { this.ename = ename; } public String getJob() { return job; } public void setJob(String job) { this.job = job; }} 2.创建一个 DBHelper 对象用以与数据库进行交互代码如下:package com.dao; import com.tool.UserData; import java.math.BigDecimal;import java.sql.*;import java.util.*;import java.util.Date; /** * Created by lx_sunwei on 14-1-6. */public class DBHelper { Connection conn; //数据库连接对象 PreparedStatement pt; //SQL语句预处理对象 ResultSet rs; //结果集对象 public DBHelper(){ try { Class.forName("oracle.jdbc.driver.OracleDriver"); //装载驱动 } catch (ClassNotFoundException e) { e.printStackTrace(); } } /** * 获取当前页的数据 * @param curPage * @param rowsPerPage * @return */ public List<UserData> getData(int curPage, int rowsPerPage) { List<UserData> dataList = new ArrayList<>(); String url = "jdbc:oracle:thin:@localhost:1521:orcl"; try { conn = DriverManager.getConnection(url,"scott","tiger"); String sql = "select * from emp where rownum <= ((? - 1) * "+rowsPerPage+" + "+rowsPerPage+") minus " + " select * from emp where rownum <= (? - 1) * "+rowsPerPage+" "; pt = conn.prepareStatement(sql); pt.setInt(1,curPage); pt.setInt(2,curPage); rs = pt.executeQuery(); while (rs.next()){ /** * 从结果集中取得数据 */ UserData userData = new UserData(); BigDecimal empno = rs.getBigDecimal("empno"); String ename = rs.getString("ename"); String job = rs.getString("job"); BigDecimal mgr = rs.getBigDecimal("mgr"); Date hireDate = rs.getDate("hiredate"); BigDecimal sal = rs.getBigDecimal("sal"); BigDecimal comm = rs.getBigDecimal("comm"); BigDecimal deptno = rs.getBigDecimal("deptno"); /** * 设置对象属性 */ userData.setEmpno(empno); userData.setEname(ename); userData.setJob(job); userData.setMgr(mgr); userData.setHireDate(hireDate); userData.setSal(sal); userData.setComm(comm); userData.setDeptno(deptno); dataList.add(userData); //把对象添加集合中 } rs.close(); pt.close(); conn.close(); } catch (SQLException e) { e.printStackTrace(); } return dataList; } /** * 返回总页数 * @return */ public int getMaxPage(int rowsPerPage) { int maxPage; int maxRowCount = 0; String url = "jdbc:oracle:thin:@localhost:1521:orcl"; try { conn = DriverManager.getConnection(url,"scott","tiger"); //创建数据库连接 String sql = "select count(*) from emp"; pt = conn.prepareStatement(sql); rs = pt.executeQuery(); if (rs.next()){ maxRowCount = rs.getInt(1); //总行数 } } catch (SQLException e) { e.printStackTrace(); } maxPage = (maxRowCount + rowsPerPage - 1) / rowsPerPage; //总页数 return maxPage; }} 3.创建 Servlet 对显示页面进行控制代码如下:package com.servlet; import com.dao.DBHelper;import com.tool.UserData; import javax.servlet.RequestDispatcher;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import java.io.IOException;import java.util.*; /** * Created by lx_sunwei on 14-1-6. */public class Servlet extends HttpServlet { public int rowsPerPage; //每页显示的行数 public int curPage; //当前页页码 public int maxPage; //总共页数 DBHelper db = new DBHelper(); public Servlet(){ rowsPerPage = 5; } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String curPage1 = request.getParameter("page"); //获取当前页页码 if (curPage1 == null){ curPage = 1; request.setAttribute("curPage",curPage); //设置curPage对象 }else { curPa

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