Java实现分页代码

在项目中，分页是一个项目中必不可少的，它可以防止我们从数据库中进行大量数据查询时速度变慢，提高我们的查询效率。

1、定义分页模型：PageModel

 package com.common.page; 

 import java.util.List; 

 /**
 * 封装分页信息
 * @author Administrator
 *
 */
 public class PageModel<E> { 

 //结果集
 private List<E> list; 

 //查询记录数
 private int totalRecords; 

 //每页多少条数据
 private int pageSize; 

 //第几页
 private int pageNo; 

 /**
  * 总页数
  * @return
  */
 public int getTotalPages() {
  return (totalRecords + pageSize - 1) / pageSize;
 } 

 /**
  * 取得首页
  * @return
  */
 public int getTopPageNo() {
  return 1;
 } 

 /**
  * 上一页
  * @return
  */
 public int getPreviousPageNo() {
  if (pageNo <= 1) {
  return 1;
  }
  return pageNo - 1;
 } 

 /**
  * 下一页
  * @return
  */
 public int getNextPageNo() {
  if (pageNo >= getBottomPageNo()) {
  return getBottomPageNo();
  }
  return pageNo + 1;
 } 

 /**
  * 取得尾页
  * @return
  */
 public int getBottomPageNo() {
  return getTotalPages();
 } 

 public List<E> getList() {
  return list;
 } 

 public void setList(List<E> list) {
  this.list = list;
 } 

 public int getTotalRecords() {
  return totalRecords;
 } 

 public void setTotalRecords(int totalRecords) {
  this.totalRecords = totalRecords;
 } 

 public int getPageSize() {
  return pageSize;
 } 

 public void setPageSize(int pageSize) {
  this.pageSize = pageSize;
 } 

 public int getPageNo() {
  return pageNo;
 } 

 public void setPageNo(int pageNo) {
  this.pageNo = pageNo;
 }
 } 

2、分页测试：在MySQL中建立admin表，里面有字段id、name、password

3、简历Admin的实体bean类：

 package com.common.page; 

 public class Admin {
 private int id;
 private String name;
 private String password;
 public int getId() {
  return id;
 }
 public void setId(int id) {
  this.id = id;
 }
 public String getName() {
  return name;
 }
 public void setName(String name) {
  this.name = name;
 }
 public String getPassword() {
  return password;
 }
 public void setPassword(String password) {
  this.password = password;
 } 

 }

4、测试调用：

 package com.common.page; 

 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 com.common.db.DbUtil; 

 public class Client {
 public static PageModel findAdmins(int pageNo,int pageSize){
  Connection conn=DbUtil.getConnection();
  String sql="select * from admin limit ?,?";
  PageModel pageModel=null;
  PreparedStatement pstm=null;
  ResultSet rs=null;
  Admin admin=null;
  List<Admin> list=new ArrayList<Admin>();
  try {
  pstm=conn.prepareStatement(sql);
  pstm.setInt(1, (pageNo-1)*pageSize);
  pstm.setInt(2, pageNo*pageSize);
  rs=pstm.executeQuery();;
  while(rs.next()){
   admin=new Admin();
   admin.setId(rs.getInt("a_id"));
   admin.setName(rs.getString("a_name"));
   admin.setPassword(rs.getString("a_pwd"));
   list.add(admin);
  }
  ResultSet rs2=pstm.executeQuery("select count(*) from admin");
  int total=0;
  if(rs2.next()){
   total=rs2.getInt(1);
  }
  pageModel=new PageModel();
  pageModel.setPageNo(pageNo);
  pageModel.setPageSize(pageSize);
  pageModel.setTotalRecords(total);
  pageModel.setList(list);
  } catch (SQLException e) {
  e.printStackTrace();
  }finally{
  DbUtil.close(conn);
  DbUtil.close(pstm);
  DbUtil.close(rs);
  }
  return pageModel;
 } 

 public static void main(String[] args) {
  PageModel pageModel=Client.findAdmins(2,4);
  List<Admin> list=pageModel.getList();
  for(Admin a:list){
  System.out.print("ID:"+a.getId()+",用户名:"+a.getName()+",密码:"+a.getPassword());
  System.out.println();
  }
  System.out.print("当前页:"+pageModel.getPageNo()+" ");
  System.out.print("共"+pageModel.getTotalPages()+"页 ");
  System.out.print("首页:"+pageModel.getTopPageNo()+" ");
  System.out.print("上一页:"+pageModel.getPreviousPageNo()+" ");
  System.out.print("下一页:"+pageModel.getNextPageNo()+" ");
  System.out.print("尾页:"+pageModel.getBottomPageNo()+" ");
  System.out.print("共"+pageModel.getTotalRecords()+"条记录");
  System.out.println();
 } 

 } 

这样分页效果就实现了，我们要实现分页效果，只要传入相应的参数和相应的数据库执行语句即可实现，希望大家能灵活运用。

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