使用Oracle中的rownum实现分页

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Scanner;

import jdbc.util.JDBCUtil;

public class Page {
private int start = 1;//页面的起始位置
private int size = 5;//每页显示的记录数
private int end = 5;//页面的终止位置
private int count = 0;//数据库中的记录数
private Connection con = null;
private PreparedStatement ps = null;
private ResultSet rs = null;
private JDBCUtil jd;//数据库连接的工具包

public Page(){
jd = new JDBCUtil();
con = jd.getCon();
}

public void getCount(){
String sqlCount = "select count(*) from student";
String sql = "select id,name,rnum from(select id,name,rownum rnum from student)" +
"where rnum between ? and ?";//为了第一次显示页面
try {
ps = con.prepareStatement(sqlCount);
rs = ps.executeQuery();
while(rs.next()){
count = rs.getInt(1);
}
ps = con.prepareStatement(sql);
ps.setInt(1,start);
ps.setInt(2,end);
rs = ps.executeQuery();
jd.printResultSet(rs);
} catch (SQLException e) {
e.printStackTrace();
}
}
public void showPage(String command) throws SQLException{
String sql = "select id,name,rnum from(select id,name,rownum rnum from student)" +
"where rnum between ? and ?";
ps = con.prepareStatement(sql);
if(command.equals("up")){
if(start - size <= 1){
System.out.println("已经是第一页了");
start = 1;
end = 5;
ps.setInt(1,start);
ps.setInt(2,end);
rs = ps.executeQuery();
jd.printResultSet(rs);
}else{
start = start - size;
end = start +  size - 1;
ps.setInt(1,start);
ps.setInt(2, end);
rs = ps.executeQuery();
jd.printResultSet(rs);
}

}else if(command.equals("next")){
if(count - start <= size ){
System.out.println("已经是最后一页");
end = count;
start = end - count%size + 1;
ps.setInt(1,start);
ps.setInt(2,end);
rs = ps.executeQuery();
jd.printResultSet(rs);
}else{
start = start + size;
end = end + size;
ps.setInt(1, start);
ps.setInt(2,end);
rs = ps.executeQuery();
jd.printResultSet(rs);
}
}else if(command.equals("exit")){
System.exit(-1);
}
}
public void insertData() throws SQLException{
int j = 0;
for (int i = 1; i < 27; i++) {
String sql = "insert into student values("+i+","+"'zhangsan"+i+"')";
ps = con.prepareStatement(sql);
j += ps.executeUpdate();
}
System.out.println(j+"条记录被执行");
}
public static void main(String[] args) throws SQLException {
Page page = new Page();
page.getCount();
//        page.insertData();
Scanner scan = new Scanner(System.in);
while(true){
System.out.println("输入next up exit指令");
String command = scan.next();
page.showPage(command.trim());
}
}
}

　　上面是控制显示页面的，下面提供JDBCUtil的工具包

package jdbc.util;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;

public class JDBCUtil {

static{
String driverName = "oracle.jdbc.driver.OracleDriver";
try {
Class.forName(driverName);
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}
public Connection getCon(){
Connection con = null;
String url = "jdbc:oracle:thin:@localhost:1521:xe";
String user = "hr";
String password = "admin";
try {
con = DriverManager.getConnection(url, user, password);
} catch (SQLException e) {
e.printStackTrace();
}
return con;
}
public void printResultSet(ResultSet rs){
ResultSetMetaData rsmd = null;
if(rs != null){
try {
rsmd = rs.getMetaData();
System.out.println("rsmd ====== >"+rsmd.getColumnCount());
} catch (SQLException e) {
e.printStackTrace();
}
try {
while(rs.next()){
for(int i=1;i <= rsmd.getColumnCount();i++){
System.out.print(rsmd.getColumnName(i)+"=");
System.out.print(rs.getString(i)+"\t");
}
System.out.println();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
}
public void release(ResultSet rs,Statement smt,Connection con){
if(rs != null)
try {
rs.close();
} catch (SQLException e) {
e.printStackTrace();
}
if(smt != null)
try {
smt.close();
} catch (SQLException e) {
e.printStackTrace();
}
if(con != null)
try {
con.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
public void release(Object...obj){
for (Object object : obj) {
if(object instanceof ResultSet)
try {
((ResultSet)object).close();
} catch (SQLException e) {
e.printStackTrace();
}
if(object instanceof Statement)
try {
((Statement)object).close();
} catch (SQLException e) {
e.printStackTrace();
}
if(object instanceof Connection)
try {
((Connection)object).close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}

　　对于释放资源使用了两种方法，release(ResultSet rs,Statement smt,Connection con)和release(Object...obj)，随便使用。