第一個檔案PagedbClass.java
| 代碼如下 |
複製代碼 |
package com.kanba.tools;
import java.sql.*;
import com.kanba.connection.Conn;
public class PagedbClass {
Connection con = null;
Statement stmt = null;
ResultSet rs = null;
ResultSetMetaData resultsMeta =null;
int rows = 0;
public PagedbClass() {
con = new Conn().getConnection();
}
public ResultSet executeQuery(String sql) throws SQLException{
ResultSet rs = null;
try{
stmt = con.createStatement();
rs = stmt.executeQuery(sql);
while(rs.next())
this.rows ++;
rs = stmt.executeQuery(sql);
}
catch (SQLException e){
System.out.print("Query:"+e.getMessage());
}
this.rs = rs;
return rs;
}
public boolean executeUpdate(String sql){
try{
stmt = con.createStatement();
stmt.executeUpdate(sql);
return true;
}
catch(SQLException e){
System.out.print("Update:"+e.getMessage());
return false;
}
}
public int getColumns(){
int columns = 0;
try{
this.resultsMeta = this.rs.getMetaData();
columns = this.resultsMeta.getColumnCount();
}
catch (SQLException e) {}
return columns;
}
public int getRows(){
return this.rows;
}
public void closedb(){
try{
con.close();
}catch(SQLException e){
e.printStackTrace();
}
}
} |
第二個檔案分頁通用類 PageQuery.java
| 代碼如下 |
複製代碼 |
package com.kanba.tools;
import java.sql.*;
import javax.servlet.http.*;
public class PageQuery {
int Offset; // 記錄位移量
int Total; // 記錄總數
int MaxLine; // 記錄每頁顯示記錄數
ResultSet rs; // 讀出的結果
int TPages; // 總頁數
int CPages; // 當前頁數
String PageQuery; // 分頁顯示要傳遞的參數
String Query; // query 語句
String QueryPart; // " FROM " 以後的 query 部分
String FilePath;
PagedbClass db; // object of dbclass
//constructer do nothing
public PageQuery() {
// 每頁顯示十行
MaxLine = 30;
db = new PagedbClass();
}
//********讀取記錄***************
// 主要工作函數，根據所給的條件從表中讀取相應的記錄
public ResultSet myQuery(String query, HttpServletRequest req) throws SQLException {
String query_part, os;
int begin, offset;
// 截取 " FROM " 以後的 query 語句
begin = query.indexOf(" FROM ");
query_part = query.substring(begin, query.length()).trim();
// 計算位移量
os = req.getParameter("offset");
if (os == null) Offset = 0;
else Offset = Integer.parseInt(os);
// 擷取檔案名稱
FilePath = req.getRequestURI();
Query = query;
QueryPart = query_part;
// 計算總的記錄條數
String SQL = "SELECT Count(*) AS total " + this.QueryPart;
rs = db.executeQuery(SQL);
if (rs.next())
Total = rs.getInt(1);
// 設定當前頁數和總頁數
TPages = (int)Math.ceil((double)this.Total/this.MaxLine);
CPages = (int)Math.floor((double)Offset/this.MaxLine+1);
// 根據條件判斷，取出所需記錄
if (Total > 0) {
SQL = Query + " LIMIT " + Offset + " , " + MaxLine;
rs = db.executeQuery(SQL);
}
return rs;
}
public void close(){
db.closedb();
}
// 顯示總頁數
public int getTotalPages() {
return TPages;
}
//顯示當前所在頁數
public int getCurrenPages() {
return CPages;
}
//**********顯示翻頁提示欄*************
// 顯示首頁、下頁、上頁、尾頁
public String PageLegend() {
String str = "";
int first, next, prev, last;
first = 0;
next = Offset + MaxLine;
prev = Offset - MaxLine;
last = (this.TPages - 1) * MaxLine;
if(Offset >= MaxLine)
str += " <A href=" + FilePath + "?offset=" + first + ">首頁</A> ";
else str += " 首頁 ";
if(prev >= 0)
str += " <A href=" + FilePath + "?offset=" + prev + ">前頁</A> ";
else str += " 前頁 ";
if(next < Total)
str += " <A href=" + FilePath + "?offset=" + next + ">後頁</A> ";
else str += " 後頁 ";
if(TPages != 0 && CPages < TPages)
str += " <A href=" + FilePath + "?offset=" + last + ">尾頁</A>";
else str += " 尾頁 ";
str += " 頁次：" + getCurrenPages() + "/" + getTotalPages() + "頁 ";
str += MaxLine + "條/頁 " + "共" + Total + "條";
String pageNum;
return str;
}
}
|
資料庫連接檔案 Conn.java
| 代碼如下 |
複製代碼 |
package com.kanba.connection
import java.sql.*;
public class Conn {
public Conn(){}
//這個是串連資料庫的代碼，也可以通過串連池等技術實現。
String driverClass="org.gjt.mm.mysql.Driver";
String url = "jdbc:mysql://localhost/test?user=root&password=0&useUnicode=true&characterEncoding=gb2312";
String username="root";
String password="pwd";
Connection conn=null; //初始化
public Connection getConnection()
{
try {
Class.forName(driverClass); //載入驅動
// System.out.println("jiazaichenggong");
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
try {
conn=DriverManager.getConnection(url); //建立串連conn
} catch (SQLException e) {
e.printStackTrace();
}
return conn;
}
}
分頁測試檔案 page.jsp
<%@ page language="java" import="java.sql.*, com.kanba.tools.*" %>
<%@ page contentType="text/html; charset=gb2312" %>
<jsp:useBean id="pq" scope="page" class="com.kanba.tools.PageQuery" />
<html>
<body bgcolor="#8BA9C9">
<table bgcolor="#fecda9" cellspacing=0>
<%
String query = "SELECT * FROM users"; // 注意這個" FROM "一定要大寫，程式中需要靠這個FROM後的query語句判斷總行數。
ResultSet rs = pq.myQuery(query, request);
String bar = pq.PageLegend(); //讀取分頁提示欄
out.println("<tr><td colspan=2>"+bar+"</td></tr>");
out.println("<tr><td colspan=2><hr size=1 color=blue></td></tr>");
while (rs.next()) {
//說明：rs.getString(2)等是列名相對應的位置，不要用rs.getString("colmn_name")這種形式
%>
<tr><td><%=rs.getString(1)%></td><td><%=rs.getString(2)%></td></tr>
<% }
rs.close;pq.close();
%>
</table>
</body>
</html> |
