标签：Java String -- request 改查 stu import public pstmt
硬件：微机 环境：idea+mysql
数据库建立：
思路：建立数据库->建立实体类->实现增删改查方法（普通Java方法+Servlet）->页面（主页面+次页面）。
连接数据库
1 package dao;
2
3 import java.sql.*;
4
5 public class DBUtil {
6 static String url="jdbc:mysql://localhost:3306/db1";
7 static String passwd="jia237106-";
8 static String user="root";
9
10 public static Connection getConnection(){
11 Connection conn=null;
12 try {
13 Class.forName("com.mysql.jdbc.Driver");
14 conn= DriverManager.getConnection(url,user,passwd);
15 System.out.println("连接成功");
16 } catch (Exception e) {
17 System.out.println("连接失败");
18 e.printStackTrace();
19 }
20 return conn;
21 }
22 public static void close(Statement stmt, Connection conn, PreparedStatement ps, ResultSet rs){
23 if(stmt!=null){
24 try {
25 stmt.close();
26 } catch (SQLException e) {
27 e.printStackTrace();
28 }
29 }
30 if(conn!=null){
31 try {
32 conn.close();
33 } catch (SQLException e) {
34 e.printStackTrace();
35 }
36 }
37 if(ps!=null){
38 try {
39 ps.close();
40 } catch (SQLException e) {
41 e.printStackTrace();
42 }
43 }
44
45 if(rs!=null){
46 try {
47 rs.close();
48 } catch (SQLException e) {
49 e.printStackTrace();
50 }
51 }
52 }
53 }
建立实体类，get和set方法
1 package entity;
2
3 public class Stud {
4 private String stuname;
5 private String id;
6 private String stuclass;
7 private String college;
8 private String phone;
9 private String health;
10 private String trip;
11 private String other0;
12
13 public String getStuname() {
14 return stuname;
15 }
16
17 public void setStuname(String stuname) {
18 this.stuname = stuname;
19 }
20
21 public String getId() {
22 return id;
23 }
24
25 public void setId(String id) {
26 this.id = id;
27 }
28
29 public String getStuclass() {
30 return stuclass;
31 }
32
33 public void setStuclass(String stuclass) {
34 this.stuclass = stuclass;
35 }
36
37 public String getCollege() {
38 return college;
39 }
40
41 public void setCollege(String college) {
42 this.college = college;
43 }
44
45 public String getPhone() {
46 return phone;
47 }
48
49 public void setPhone(String phone) {
50 this.phone = phone;
51 }
52
53 public String getHealth() {
54 return health;
55 }
56
57 public void setHealth(String health) {
58 this.health = health;
59 }
60
61 public String getTrip() {
62 return trip;
63 }
64
65 public void setTrip(String trip) {
66 this.trip = trip;
67 }
68
69 public String getOther0() {
70 return other0;
71 }
72
73 public void setOther0(String other0) {
74 this.other0 = other0;
75 }
76 }
实现增删改查方法和Servlet
1、增
1 package dao;
2
3 import entity.Stud;
4
5 import java.sql.Connection;
6 import java.sql.PreparedStatement;
7 import java.sql.ResultSet;
8 import java.sql.SQLException;
9
10 public class Add {
11 Connection conn=(Connection) DBUtil.getConnection();
12
13 public boolean add(Stud stu){
14 boolean flag=false;
15 ResultSet rs=null;
16 String sql="insert into stud values(?,?,?,?,?,?,?,?)";
17 try {
18 PreparedStatement pstmt= conn.prepareStatement(sql);
19 pstmt.setString(1,stu.getStuname());
20 pstmt.setString(2, stu.getId());
21 pstmt.setString(3,stu.getStuclass());
22 pstmt.setString(4, stu.getCollege());
23 pstmt.setString(5, stu.getPhone());
24 pstmt.setString(6,stu.getHealth());
25 pstmt.setString(7,stu.getTrip());
26 pstmt.setString(8,stu.getOther0());
27 int i= pstmt.executeUpdate();
28 pstmt.close();
29 conn.close();
30 if(i>0) flag=true;
31 } catch (SQLException e) {
32 e.printStackTrace();
33 }
34 return flag;
35 }
36 }
1 package Servlet;
2
3 import dao.Add;
4 import entity.Stud;
5
6 import javax.servlet.*;
7 import javax.servlet.http.*;
8 import javax.servlet.annotation.*;
9 import java.io.IOException;
10 import java.util.Arrays;
11
12 @WebServlet(name = "addServlet", value = "/addServlet")
13 public class addServlet extends HttpServlet {
14 @Override
15 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
16 request.setCharacterEncoding("UTF-8");
17 response.setContentType("text/html;charset=utf-8");
18
19 String stuname=request.getParameter("stuname");
20 String id=request.getParameter("id");
21 String stuclass=request.getParameter("stuclass");
22 String college=request.getParameter("college");
23 String phone=request.getParameter("phone");
24 String health=request.getParameter("health");
25 String [] h=request.getParameterValues("trip");
26 String trip=Arrays.toString(h);
27 trip=trip.substring(1,trip.length()-1);
28 String other0=request.getParameter("other0");
29
30
31 Stud stud=new Stud();
32 stud.setStuname(stuname);
33 stud.setId(id);
34 stud.setStuclass(stuclass);
35 stud.getStuclass();
36 stud.setCollege(college);
37 stud.setPhone(phone);
38 stud.setHealth(health);
39 stud.setTrip(trip);
40 stud.setOther0(other0);
41 Add s=new Add();
42 try{
43 s.add(stud);
44 response.sendRedirect(request.getContextPath()+"/success.jsp");
45 }catch(Exception e){
46 response.sendRedirect(request.getContextPath()+"/fail.jsp");
47 }
48 }
49 }
2、删
1 package dao;
2
3 import entity.Stud;
4
5 import java.sql.Connection;
6 import java.sql.PreparedStatement;
7 import java.sql.SQLException;
8
9 public class Delete {
10 Connection conn=DBUtil.getConnection();
11
12 public boolean delete(Stud stu){
13 boolean flag=false;
14 String sql="delete from stud where id=?";
15 try {
16 PreparedStatement pstmt= conn.prepareStatement(sql);
17 pstmt.setString(1,stu.getId());
18 int i=pstmt.executeUpdate();
19 pstmt.close();
20 conn.close();
21 if(i>0) flag=true;
22 } catch (SQLException e) {
23 e.printStackTrace();
24 }
25 return flag;
26 }
27 }
1 package deleteServlet;
2
3 import dao.Delete;
4 import entity.Stud;
5
6 import javax.servlet.*;
7 import javax.servlet.http.*;
8 import javax.servlet.annotation.*;
9 import java.io.IOException;
10
11 @WebServlet(name = "delete", value = "/delete")
12 public class delete extends HttpServlet {
13 private static final long serialVersionUID = 1L;
14 @Override
15 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
16 doPost(request,response);
17 }
18
19 @Override
20 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
21 request.setCharacterEncoding("UTF-8");
22 response.setContentType("text/html;charset=utf-8");
23
24 String id=request.getParameter("id");
25 Stud stu=new Stud();
26 stu.setId(id);
27 Delete d=new Delete();
28 try{
29 d.delete(stu);
30 response.sendRedirect(request.getContextPath()+"/main.jsp");
31 }catch (Exception e){
32 System.out.println("删除失败");
33 e.printStackTrace();
34 }
35 }
36 }
3、改
1 package dao;
2
3 import entity.Stud;
4
5 import java.sql.Connection;
6 import java.sql.PreparedStatement;
7 import java.sql.Statement;
8
9 //根据学号修改
10 public class update {
11 Connection conn=DBUtil.getConnection();
12 public boolean update(Stud stu){
13 boolean flag=false;
14 String sql="update stud set stuname=?,stuclass=?,college=?,phone=?,health=?,trip=?,other0=?where id=?";
15 Statement state=null;
16 try{
17 PreparedStatement pstmt= conn.prepareStatement(sql);
18 pstmt.setString(1,stu.getStuname());
19 pstmt.setString(2,stu.getStuclass());
20 pstmt.setString(3,stu.getCollege());
21 pstmt.setString(4,stu.getPhone());
22 pstmt.setString(5,stu.getHealth());
23 pstmt.setString(6,stu.getTrip());
24 pstmt.setString(7,stu.getOther0());
25 pstmt.setString(8,stu.getId());
26 int i=pstmt.executeUpdate();
27 if(i>0) flag=true;
28 pstmt.close();
29 conn.close();
30 }catch(Exception e){
31 e.printStackTrace();
32 }
33 return flag;
34 }
35 }
1 package UpdateServlet;
2
3 import dao.update;
4 import entity.Stud;
5
6 import javax.servlet.*;
7 import javax.servlet.http.*;
8 import javax.servlet.annotation.*;
9 import java.io.IOException;
10 import java.util.Arrays;
11
12 @WebServlet(name = "udate", value = "/udate")
13 public class udate extends HttpServlet {
14 @Override
15 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
16
17 }
18
19 @Override
20 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
21 request.setCharacterEncoding("UTF-8");
22 response.setContentType("text/html,charset=utf-8");
23 String stuname=request.getParameter("stuname");
24 String id=request.getParameter("id");
25 String stuclass=request.getParameter("stuclass");
26 String college=request.getParameter("college");
27 String phone=request.getParameter("phone");
28 String health=request.getParameter("health");
29 String [] h=request.getParameterValues("trip");
30 String trip= Arrays.toString(h);
31 trip=trip.substring(1,trip.length()-1);
32 String other0=request.getParameter("other0");
33
34 Stud stud=new Stud();
35 stud.setStuname(stuname);
36 stud.setId(id);
37 stud.setStuclass(stuclass);
38 stud.getStuclass();
39 stud.setCollege(college);
40 stud.setPhone(phone);
41 stud.setHealth(health);
42 stud.setTrip(trip);
43 stud.setOther0(other0);
44
45 update u=new update();
46 try{
47 u.update(stud);
48 response.sendRedirect(request.getContextPath()+"/main.jsp");
49 }catch(Exception e){
50 System.out.println("修改失败");
51 e.printStackTrace();
52 }
53 }
54 }
4、查，根据id查询
1 package dao;
2
3 import entity.Stud;
4
5 import java.sql.Connection;
6 import java.sql.PreparedStatement;
7 import java.sql.ResultSet;
8 import java.util.ArrayList;
9 import java.util.List;
10
11 public class Search {
12 static int i=1;
13 public int searchid(ArrayList<Stud> studs,String id){
14 Connection conn=DBUtil.getConnection();
15 // List<Stud> list=new ArrayList<Stud>();
16 try{
17 String sql="select * from stud where id=?";
18 PreparedStatement pstmt=conn.prepareStatement(sql);
19 pstmt.setString(1,id);
20 ResultSet rs= pstmt.executeQuery();
21 System.out.println(rs);
22 if(rs==null) i=0;
23 else {
24 while (rs.next()) {
25 Stud stu = new Stud();
26 stu.setStuname(rs.getNString("stuname"));
27 stu.setId(rs.getString("id"));
28 stu.setStuclass(rs.getString("stuclass"));
29 stu.setCollege(rs.getString("college"));
30 stu.setPhone(rs.getString("phone"));
31 stu.setHealth(rs.getString("health"));
32 stu.setTrip(rs.getString("trip"));
33 stu.setOther0(rs.getString("other0"));
34 studs.add(stu);
35 }
36 }
37 rs.close();
38 pstmt.close();
39 conn.close();
40 }catch(Exception e){
41 e.printStackTrace();
42 }
43 return i;
44 }
45 }
1 package searchServlet;
2
3 import dao.Search;
4 import entity.Stud;
5
6 import javax.servlet.*;
7 import javax.servlet.http.*;
8 import javax.servlet.annotation.*;
9 import java.io.IOException;
10 import java.io.PrintWriter;
11 import java.io.Writer;
12 import java.util.ArrayList;
13 import java.util.List;
14
15 @WebServlet("/search")
16 public class search extends HttpServlet {
17 private static final long serialVersionUID = 1L;
18 public search(){
19 super();
20 }
21 @Override
22 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
23 doPost(request,response);
24 }
25
26 @Override
27 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
28 request.setCharacterEncoding("utf-8");
29 response.setContentType("text/html;charset=utf-8");
30
31 int a=0;
32 String n=request.getParameter("id");
33 ArrayList<Stud> stu=new ArrayList<Stud>();
34 System.out.println(n);
35 Search search=new Search();
36 // if(n!=null){
37 try{
38 a=search.searchid(stu,n);
39 }catch(Exception e){
40 e.printStackTrace();
41 }
42 if(a==1) {
43 request.setAttribute("id", stu);
44 request.getRequestDispatcher("search.jsp").forward(request, response);
45 }
46 else{
47 response.getWriter().write("输入数据不存在");
48 }
49 }
50 }
各个.jsp
主页面
1 <%-- 2 Created by IntelliJ IDEA. 3 User: 贾梓钊 4 Date: 2021/11/11 5 Time: 17:02 6 To change this template use File | Settings | File Templates. 7 --%> 8 <%@ page contentType="text/html;charset=UTF-8" language="java" %> 9 <html> 10 <head> 11 <title>主界面</title> 12 </head> 13 <body> 14 <div id="addSubjectForm" align="center"> 15 <form action="addServlet" method="post"> 16 <tr> 17 <td>行程信息管理系统</td> 18 </tr> 19 <ul> 20 <li><a href="add.jsp">信息添加</a></li> 21 <li><a href="delete.jsp">信息删除</a></li> 22 <li><a href="update.jsp">信息修改</a></li> 23 <li><a href="search1.html">信息查询</a> </li> 24 </ul> 25 </form> 26 27 </div> 28 </body> 29 </html>
添加页面，有添加提示页面，这里就不展示了（特别简单）
1 <%-- 2 Created by IntelliJ IDEA. 3 User: 贾梓钊 4 Date: 2021/11/5 5 Time: 14:13 6 To change this template use File | Settings | File Templates. 7 --%> 8 <%@ page contentType="text/html;charset=UTF-8" language="java" %> 9 <html> 10 <head> 11 <meta charset="UTF-8"> 12 <title>行程统计</title> 13 </head> 14 <body bgcolor="aqua"> 15 <p align="center">行程信息统计系统</p> 16 <div id="addSubjectForm" align="center"> 17 <form action="addServlet" method="post"> 18 <tr> 19 <td>姓名:</td> 20 <td><input type="text" name="stuname" size="20"><br></td> 21 </tr> 22 <tr> 23 <td>学号:</td> 24 <td><input type="text" name="id" size="20"><br></td> 25 </tr> 26 <tr> 27 <td>学生类别:</td> 28 <td><input type="radio" name="stuclass" value="本科生">本科生 29 <input type="radio" name="stuclass" value="研究生">研究生 30 </td> 31 </tr> 32 <br> 33 <tr> 34 <td>电话：</td> 35 <td><input type="text" name="phone" size="20"> 36 </tr> 37 <br> 38 <tr> 39 <td>院系：</td> 40 <select name="college"> 41 <option value="土木学院">土木学院</option> 42 <option value="机械学院" >机械学院</option> 43 <option value="交通学院" >交通学院</option> 44 <option value="信息学院" >信息学院</option> 45 <option value="经管学院" >经管学院</option> 46 </select> 47 </tr> 48 <br> 49 <tr> 50 <td>健康码：</td> 51 <td><input type="checkbox" name="health" value="绿色">绿色 52 <input type="checkbox" name="health" value="黄色">黄色 53 <input type="checkbox" name="health" value="红色">红色</td> 54 </tr> 55 <br> 56 <tr> 57 <td>行程统计：</td> 58 <td> 59 <input type="checkbox" name="trip" value="10月30日去过人民医院">10月30日去过人民医院<br> 60 <input type="checkbox" name="trip" value="10月25日以来去过深泽县人民医院">10月25日以来去过深泽县人民医院<br> 61 <input type="checkbox" name="trip" value="10月16日以来去过深泽县庄泽村">10月16日以来去过深泽县庄泽村<br> 62 <input type="checkbox" name="trip" value="10月29日以来去过黑龙江哈尔滨市或者黑河市">10月29日以来去过黑龙江哈尔滨市或者黑河市<br> 63 <input type="checkbox" name="trip" value="10月18日以来途径贵州遵义市；北京丰台、昌平">10月18日以来途径贵州遵义市；北京丰台、昌平<br> 64 <input type="checkbox" name="trip" value="10月17日以来到过湖南长沙；青海海东市">10月17日以来到过湖南长沙；青海海东市<br> 65 </td> 66 </tr> 67 <br> 68 <tr> 69 <td>其他涉疫信息需要填报的:</td> 70 <td><input type="text" name="other0" size="50"><br></td> 71 </tr> 72 <tr> 73 <td colspan="2"><div align="center"><input type="submit" value="提交"> 74 </div> 75 </form> 76 </div> 77 </body> 78 </html>
删除页面
1 <%-- 2 Created by IntelliJ IDEA. 3 User: 贾梓钊 4 Date: 2021/11/11 5 Time: 16:56 6 To change this template use File | Settings | File Templates. 7 --%> 8 <%@ page contentType="text/html;charset=UTF-8" language="java" %> 9 <html> 10 <head> 11 <title>删除界面</title> 12 </head> 13 <body bgcolor="aqua"> 14 <p align="center">行程信息删除</p> 15 <div id="addSubjectForm" align="center"> 16 <form action="delete" method="post"> 17 <tr> 18 <td>请输入要删除信息的学号：</td> 19 <td><input type="text" name="id" size="20"></td><br> 20 </tr> 21 <tr> 22 <td colspan="2"> 23 <div align="center"> 24 <input type="submit" value="删除"> 25 </div> 26 27 </td> 28 </tr> 29 </form> 30 </div> 31 32 </body> 33 </html>
修改页面
1 <%-- 2 Created by IntelliJ IDEA. 3 User: 贾梓钊 4 Date: 2021/11/11 5 Time: 18:01 6 To change this template use File | Settings | File Templates. 7 --%> 8 <%@ page contentType="text/html;charset=UTF-8" language="java" %> 9 <html> 10 <head> 11 <title>修改界面</title> 12 <meta charset="UTF-8"> 13 </head> 14 <body> 15 <p align="center">行程信息修改</p> 16 <div id="addSubject" align="center"> 17 <form action="udate" method="post"> 18 <tr> 19 <td>姓名:</td> 20 <td><input type="text" name="stuname" size="20"><br></td> 21 </tr> 22 <tr> 23 <td>学号:</td> 24 <td><input type="text" name="id" size="20"><br></td> 25 </tr> 26 <tr> 27 <td>学生类别:</td> 28 <td><input type="radio" name="stuclass" value="本科生">本科生 29 <input type="radio" name="stuclass" value="研究生">研究生 30 </td> 31 </tr> 32 <br> 33 <tr> 34 <td>电话：</td> 35 <td><input type="text" name="phone" size="20"> 36 </tr> 37 <br> 38 <tr> 39 <td>院系：</td> 40 <select name="college"> 41 <option value="土木学院">土木学院</option> 42 <option value="机械学院" >机械学院</option> 43 <option value="交通学院" >交通学院</option> 44 <option value="信息学院" >信息学院</option> 45 <option value="经管学院" >经管学院</option> 46 </select> 47 </tr> 48 <br> 49 <tr> 50 <td>健康码：</td> 51 <td><input type="checkbox" name="health" value="绿色">绿色 52 <input type="checkbox" name="health" value="黄色">黄色 53 <input type="checkbox" name="health" value="红色">红色</td> 54 </tr> 55 <br> 56 <tr> 57 <td>行程统计：</td> 58 <td> 59 <input type="checkbox" name="trip" value="10月30日去过人民医院">10月30日去过人民医院<br> 60 <input type="checkbox" name="trip" value="10月25日以来去过深泽县人民医院">10月25日以来去过深泽县人民医院<br> 61 <input type="checkbox" name="trip" value="10月16日以来去过深泽县庄泽村">10月16日以来去过深泽县庄泽村<br> 62 <input type="checkbox" name="trip" value="10月29日以来去过黑龙江哈尔滨市或者黑河市">10月29日以来去过黑龙江哈尔滨市或者黑河市<br> 63 <input type="checkbox" name="trip" value="10月18日以来途径贵州遵义市；北京丰台、昌平">10月18日以来途径贵州遵义市；北京丰台、昌平<br> 64 <input type="checkbox" name="trip" value="10月17日以来到过湖南长沙；青海海东市">10月17日以来到过湖南长沙；青海海东市<br> 65 </td> 66 </tr> 67 <br> 68 <tr> 69 <td>其他涉疫信息需要填报的:</td> 70 <td><input type="text" name="other0" size="50"><br></td> 71 </tr> 72 <tr> 73 <td colspan="2"><div align="center"><input type="submit" value="修改"> 74 </div> 75 </form> 76 </div> 77 </body> 78 </html>
删除页面，一个.jsp页面和一个.html界面，html前端跳转到.jsp（输出格式），接受servlet的信息并输出
.html
1 <!DOCTYPE html> 2 <html lang="en"> 3 <head> 4 <meta charset="UTF-8"> 5 <title>Title</title> 6 </head> 7 <body> 8 <div id="addSubjectForm" align="center"> 9 <form action="search" method="post"> 10 <tr> 11 <h2>请输入学号：</h2> 12 <td><input type="text" name="id" size="20"></td> 13 </tr> 14 <td> 15 <input type="submit" value="查询"> 16 </td> 17 </form> 18 </div> 19 </body> 20 </html>
.jsp
1 <%--
2 Created by IntelliJ IDEA.
3 User: 贾梓钊
4 Date: 2021/11/12
5 Time: 9:04
6 To change this template use File | Settings | File Templates.
7 --%>
8 <%@ page contentType="text/html;charset=UTF-8" language="java" %>
9 <%@page import="dao.DBUtil" %>
10 <%@page import="searchServlet.search" %>
11 <%@page import="java.util.ArrayList" %>
12 <%@page import="java.util.List" %>
13 <%@page import="entity.Stud" %>
14 <html>
15 <head>
16 <title>查询</title>
17 <meta charset="UTF-8">
18 </head>
19 <body>
20 <table border="1">
21 <tr>
22 <th>学生姓名</th>
23 <th>学号</th>
24 <th>学生类别</th>
25 <th>学院</th>
26 <th>电话</th>
27 <th>健康码</th>
28 <th>行程</th>
29 <th>其他</th>
30 </tr>
31 <%
32 ArrayList<Stud> stu=(ArrayList<Stud>) request.getAttribute("id");
33 for(int i=0;i< stu.size();i++){
34 Stud m=stu.get(i);
35 %>
36 <tr>
37 <td><%=m.getStuname()%></td>
38 <td><%=m.getId()%></td>
39 <td><%=m.getStuname()%></td>
40 <td><%=m.getCollege()%></td>
41 <td><%=m.getPhone()%></td>
42 <td><%=m.getHealth()%></td>
43 <td><%=m.getTrip()%></td>
44 <td><%=m.getOther0()%></td>
45 </tr>
46
47 <%
48 }
49 %>
50 </table>
51 </body>
52 </html>
运行界面
这次的期中考试收获还是很多的，对于.html和.jsp的应用更加熟练，但是对于Servlet的操作还是不太熟悉。
标签：Java,String,--,request,改查,stu,import,public,pstmt 来源： https://www.cnblogs.com/jzz-111jy/p/15547448.html
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