分页查询
1.创建web工程
2.连接数据库引入jar包 classes12.jar
ojdbc14.jar
放入lib中
3.指定一个jsp页面中的一个链接，跳转到一个Servlet上
4.创建一个Servlet，勾选上doget，dopost方法，Next后，Servlet/JSP Mapping URL:要从根目录跳转，删去前面一部分，留下/PageServlet
5.web.xml中配置会自动生成
6.因为要跳转到servlet上，所以index.jsp中a标签href路径是PageServlet
7.链接默认请求方式是get，只有表单请求方式是post，所以PageServlet在doget中写，dopost中流拼的网页都删了，请求方式改为this.doGet(request,response);
8.doget中调整字符集
request.setCharacterEncoding("utf-8");
response.setContentType("text/html;charset=utf-8");
9.引入DB类，负责连接关闭数据库（DB中用static修饰，背的类直接引用，不用实例化了）
10.doget中接着写调用JDBC连接数据库 ResultSet rs=DB.getCon().createStatement().executeQuery(sql); （执行完sql返回一个ResultSet值）
分页查询sql语句：
int cpage=1;
String sql="select * from " +
"(select t.*, rownum r from " +
"(select * from t_client order by client_no) t)" +
" where r between "+(cpage*3-2)+" and "+(cpage*3)+"";
11.循环rs，封装成对象，放入List集合中
创建实体类Client，提供set，get，构造方法
声明集合 List<Client> list=new ArrayList<Client>();
循环rs取值：
while(rs.next()){
String clientNo=rs.getString("client_no");
String clientName=rs.getString("client_name");
String sex=rs.getString("sex");
String birthday=rs.getString("birthday");
String certificateNO=rs.getString("CERTIFICATE_NO");
String telNO=rs.getString("tel_no");
String clientType=rs.getString("client_type");
String cardNo=rs.getString("card_no");
每一条记录封装成一个对象
Client client=new Client(clientNo, clientName, sex, birthday, certificateNO, telNO, clientType, cardNo);
循环出来的对象存入集合中
list.add(client);
12.list存入作用域中
request.setAttribute("list", list);
13.转发跳转页面
request.getRequestDispatcher("b.jsp").forward(request, response);
14.创建b.jsp显示页面，在这里取List
${requestScope.list }
循环取出
<c:forEach items="${requestScope.list }" var="client">
<tr>
<td>
<c:out value="${client.clientNo}"></c:out>
</td>
<td>
<c:out value="${client.clientName}"></c:out>
</td>
<td>
<c:out value="${client.sex}"></c:out>
</td>
</tr>
</c:forEach>
15.b.jsp上点下一页按钮再跳回PageServlet上
<a href="PageServlet?cpage=${requestScope.cpage+1 }">下一页</a>
16.PageServlet上接收，再跳到b.jsp上
if(request.getParameter("cpage")!=null){
cpage=Integer.parseInt(request.getParameter("cpage"));
} // 因为前面声明首页数 int cpage=1;所以进行判断,不然页码数永远是1
设置最新的cpage页码数: request.setAttribute("cpage", Integer.valueOf(cpage));
主页index.jsp
1 index.jsp主页 2 3 <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%> 4 <% 5 String path = request.getContextPath(); 6 String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; 7 %> 8 9 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> 10 <html> 11 <head> 12 <base href="<%=basePath%>"> 13 14 <title>My JSP ‘index.jsp‘ starting page</title> 15 <meta http-equiv="pragma" content="no-cache"> 16 <meta http-equiv="cache-control" content="no-cache"> 17 <meta http-equiv="expires" content="0"> 18 <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> 19 <meta http-equiv="description" content="This is my page"> 20 <!-- 21 <link rel="stylesheet" type="text/css" href="styles.css"> 22 --> 23 </head> 24 25 <body> 26 <a href="PageServlet">分页查询</a> 27 </body> 28 </html>
引入DB类连接关闭数据库
1 DB
2
3 package com.neusoft.db;
4
5 import java.sql.Connection;
6 import java.sql.DriverManager;
7 import java.sql.SQLException;
8
9 public class DB { //负责数据库的连接和关闭
10
11 static Connection con;
12 //连接
13
14 public static Connection getCon(){
15 try {
16 Class.forName("oracle.jdbc.driver.OracleDriver");
17 con = DriverManager.getConnection("jdbc:oracle:thin:@127.0.0.1:1521:XE","lihengyu","lihengyu");
18 System.out.println("数据库已连接");
19
20 } catch (ClassNotFoundException e) {
21 // TODO Auto-generated catch block
22 e.printStackTrace();
23 } catch (SQLException e) {
24 // TODO Auto-generated catch block
25 e.printStackTrace();
26 }finally{
27
28 return con;
29 }
30
31 }
32
33 //关闭
34 public static void conClose(){
35 try {
36 con.close();
37 } catch (SQLException e) {
38 // TODO Auto-generated catch block
39 e.printStackTrace();
40 }
41
42 }
43
44 }
实体类
1 实体类
2
3 package com.neusoft.pojo;
4
5 public class Client { //客户对象 ---对应客户表 对象的属性---表中的字段 一行记录---一个对象
6
7 String clientNo;
8 String clientName;
9 String sex;
10 String birthday;
11 String certificateNO;
12 String telNO;
13 String clientType;
14 String cardNo;
15
16 public String getClientNo() {
17 return clientNo;
18 }
19 public void setClientNo(String clientNo) {
20 this.clientNo = clientNo;
21 }
22 public String getClientName() {
23 return clientName;
24 }
25 public void setClientName(String clientName) {
26 this.clientName = clientName;
27 }
28 public String getSex() {
29 return sex;
30 }
31 public void setSex(String sex) {
32 this.sex = sex;
33 }
34 public String getBirthday() {
35 return birthday;
36 }
37 public void setBirthday(String birthday) {
38 this.birthday = birthday;
39 }
40 public String getCertificateNO() {
41 return certificateNO;
42 }
43 public void setCertificateNO(String certificateNO) {
44 this.certificateNO = certificateNO;
45 }
46 public String getTelNO() {
47 return telNO;
48 }
49 public void setTelNO(String telNO) {
50 this.telNO = telNO;
51 }
52 public String getClientType() {
53 return clientType;
54 }
55 public void setClientType(String clientType) {
56 this.clientType = clientType;
57 }
58 public String getCardNo() {
59 return cardNo;
60 }
61 public void setCardNo(String cardNo) {
62 this.cardNo = cardNo;
63 }
64 public Client() {
65
66 }
67 public Client(String clientNo, String clientName, String sex,
68 String birthday, String certificateNO, String telNO,
69 String clientType, String cardNo) {
70
71 this.clientNo = clientNo;
72 this.clientName = clientName;
73 this.sex = sex;
74 this.birthday = birthday;
75 this.certificateNO = certificateNO;
76 this.telNO = telNO;
77 this.clientType = clientType;
78 this.cardNo = cardNo;
79 }
80
81 }
servlet
1 servlet
2
3 package com.neusoft.servlet;
4
5 import java.io.IOException;
6 import java.io.PrintWriter;
7 import java.sql.ResultSet;
8 import java.sql.SQLException;
9 import java.util.ArrayList;
10 import java.util.List;
11
12 import javax.servlet.ServletException;
13 import javax.servlet.http.HttpServlet;
14 import javax.servlet.http.HttpServletRequest;
15 import javax.servlet.http.HttpServletResponse;
16
17 import com.neusoft.db.DB;
18 import com.neusoft.pojo.Client;
19
20 public class PageServlet extends HttpServlet {
21
22
23 public void doGet(HttpServletRequest request, HttpServletResponse response)
24 throws ServletException, IOException {
25 request.setCharacterEncoding("utf-8");
26 response.setContentType("text/html;charset=utf-8");
27
28 List<Client> list=new ArrayList<Client>();
29 //调用JDBC连接数据库
30 ResultSet rs;
31 int cpage=1;
32
33 if(request.getParameter("cpage")!=null){
34 cpage=Integer.parseInt(request.getParameter("cpage"));
35
36 }
37
38 String sql="select * from " +
39 "(select t.*, rownum r from " +
40 "(select * from t_client order by client_no) t)" +
41 " where r between "+(cpage*3-2)+" and "+(cpage*3)+"";
42
43
44 try {
45 rs=DB.getCon().createStatement().executeQuery(sql);
46 while(rs.next()){
47 String clientNo=rs.getString("client_no");
48 String clientName=rs.getString("client_name");
49 String sex=rs.getString("sex");
50 String birthday=rs.getString("birthday");
51 String certificateNO=rs.getString("CERTIFICATE_NO");
52 String telNO=rs.getString("tel_no");
53 String clientType=rs.getString("client_type");
54 String cardNo=rs.getString("card_no");
55
56 //封装客户对象
57 Client client=new Client(clientNo, clientName, sex, birthday, certificateNO, telNO, clientType, cardNo);
58
59 //将客户对象存入集合中
60 list.add(client);
61
62 }
63
64 request.setAttribute("list", list);
65 request.setAttribute("cpage", Integer.valueOf(cpage));
66 request.getRequestDispatcher("b.jsp").forward(request, response);
67
68 } catch (SQLException e) {
69 // TODO Auto-generated catch block
70 e.printStackTrace();
71 }
72
73 }
74
75
76 public void doPost(HttpServletRequest request, HttpServletResponse response)
77 throws ServletException, IOException {
78
79 this.doGet(request, response);
80 }
81
82 }
显示页面
1 b.jsp显示页面
2
3 <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
4 <%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
5 <%
6 String path = request.getContextPath();
7 String basePath = request.getScheme() + "://"
8 + request.getServerName() + ":" + request.getServerPort()
9 + path + "/";
10 %>
11
12 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
13 <html>
14 <head>
15 <base href="<%=basePath%>">
16
17 <title>My JSP ‘b.jsp‘ starting page</title>
18
19 <meta http-equiv="pragma" content="no-cache">
20 <meta http-equiv="cache-control" content="no-cache">
21 <meta http-equiv="expires" content="0">
22 <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
23 <meta http-equiv="description" content="This is my page">
24 <!--
25 <link rel="stylesheet" type="text/css" href="styles.css">
26 -->
27
28 </head>
29
30 <body>
31
32 <table border="1" width="800">
33 <tr>
34 <td>
35 客户编号
36 </td>
37 <td>
38 客户姓名
39 </td>
40 <td>
41 客户性别
42 </td>
43 <td>
44 生日
45 </td>
46 <td>
47 证书编号
48 </td>
49 <td>
50 电话号
51 </td>
52 <td>
53 类型
54 </td>
55 <td>
56 卡号
57 </td>
58 </tr>
59 <c:forEach items="${requestScope.list }" var="client">
60 <tr>
61 <td>
62 <c:out value="${client.clientNo}"></c:out>
63 </td>
64 <td>
65 <c:out value="${client.clientName}"></c:out>
66 </td>
67 <td>
68 <c:out value="${client.sex}"></c:out>
69 </td>
70 <td>
71 <c:out value="${client. birthday}"></c:out>
72 </td>
73 <td>
74 <c:out value="${client.certificateNO}"></c:out>
75 </td>
76 <td>
77 <c:out value="${client.telNO}"></c:out>
78 </td>
79 <td>
80 <c:out value="${client.clientType}"></c:out>
81 </td>
82 <td>
83 <c:out value="${client.cardNo}"></c:out>
84 </td>
85 </tr>
86 </c:forEach>
87
88 </table>
89
90 <a href="PageServlet?cpage=${requestScope.cpage+1 }">下一页</a>
91 </body>
92 </html>
执行结果
