Java分页代码的实现

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。