<%@ page contentType="text/html;charset=UTF-8" language="java" %> <%@ page import="java.sql.*" %> <html> <head> <title>JSP读取数据库</title> </head> <body> <table border="1" align="center"> <tr> <th>书号</th> <th>书名</th> <th>作者</th> <th>出版社</th> </tr> <% String url="jdbc:mysql://localhost:3306/hhstu?serverTimezone=Asia/test1"; //自己修改 String user="root";//MySQ帐号 String password="123456";//MYSQL密码 Connection conn ; try { Class.forName("com.mysql.jdbc.Driver"); conn = DriverManager.getConnection(url,user,password); Statement stmt=conn.createStatement(); ResultSet rs=stmt.executeQuery("SELECT * FROM books"); while(rs.next()){ %> <tr> <td><%= rs.getInt("bookid") %></td> <td><%= rs.getString("bookname") %></td> <td><%= rs.getString("writer") %></td> <td><%= rs.getString("publish") %></td> </tr> <% } //end while }//end try catch(Exception ex){ ex.printStackTrace(); } %> </table> </body> </html>修改代码

讲解<%@ page contentType="text/html; charset=utf-8" language="java" import="java.sql." errorPage=""%> <%@ page import="com.dao.BookDAO"%> <%@ page import="com.actionForm.BookForm"%> <%@ page import="java.util."%> <html> <% Collection coll = (Collection) req

charset=utf-8"> <title>图书列表</title> </head> <body> <h2>图书列表</h2> <table border="1" cellspacing="0" cellpadding="0"> <tr> <td>编号</td> <td>书名</td> <td>作者</td> <td>出版社</td> </tr> <% for...

检查<?xml version="1.0" encoding="UTF-8" ?> <%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@ page import="java.sql.DriverManager" %> <%@ page import="java.sql.Connection" %> <%! Connection connection = null; try { String url = "jdbc:postgresql://localhost:5432/postgres"; String username = "postgres"; String password = "postgres"; // 获取数据库连接 connection = DriverManager.getConnection(url, username, password); } catch (Exception e) { e.printStackTrace(); } %> <% if (connection != null) { out.println("数据库连接成功！"); } else { out.println("数据库连接失败！"); } %>

该代码片段首先通过<%@ page %>指令设置页面的编码为UTF-8，然后导入了java.sql.DriverManager和java.sql.Connection两个类。在<%! %>标签中，定义了一个connection变量，并在try-catch块中尝试建立与...

<%@ page contentType="text/html;charset=UTF-8" language="java" %> <%@page import="java.sql.*" %> <jsp:useBean id="conn" class="chapt12.ConnDB" scope="page"></jsp:useBean> <% ResultSet rs=conn.executeQuery("select title from info order by id desc"); if (rs.next()){ do { out.print(""+rs.getString(1)+""); }while (rs.next()); }else { out.print("暂无公告信息!"); } %>

1. 首先通过<jsp:useBean>标签引入ConnDB类，ConnDB类是一个JavaBean，用于创建数据库连接和执行SQL语句。 2. 然后调用ConnDB类的executeQuery方法执行SQL语句"select title from info order by id desc"，该语句的...

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@ page import="java.util., java.sql."%> <%@ page import="com.util.SQLConn"%> <%@page import="java.net.HttpURLConnection"%> <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %> <%@ taglib prefix="fmt" uri="http://java.sun.com/jsp/jstl/fmt" %> <!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>Insert Data</title> </head> <body> <%-- 获取前端数据 --%> <% String username = request.getParameter("username"); String usernum = request.getParameter("usernum"); String stime = request.getParameter("stime"); String people = request.getParameter("people"); %> <%-- 定义SQLConn类和INSERT_SQL常量 --%> <% Connection conn = SQLConn.openDB(); //创建Statement , 执行 SQL 查询 Statement sm=ct.createStatement(); //查询用户名登陆状态 String sql; sql ="select Login from User_ZC where UserId='"+usernum+"' and Login='"+1+"' "; // 执行查询 ResultSet rs = sm.executeQuery(sql); if(rs.next()) { //用户在登陆状态 int dbpass = rs.getInt(1); //System.out.println(dbpass); if(dbpass>0){ //用户合法，可以进行预约}第 31 行。错误信息是 "ct cannot be resolved"。

在代码中，你创建了一个名为 "conn" 的 Connection 对象，但在第 31 行中使用了一个名为 "ct" 的 Statement 对象，这导致了编译错误 "ct cannot be resolved"。你需要将第 31 行中的 "ct" 改为 "conn"，或者在代码中...

<%@ page language="java" import="java.util., java.sql." pageEncoding="utf-8"%> <%@page import="com.util.SQLConn"%> <%@page import="org.apache.commons.lang3.*" %> <%@page import="com.util.LOGS" %> <html> <body> <%-- 获取前端数据 --%> <% String username = request.getParameter("username"); String usernum = request.getParameter("usernum"); String name=request.getParameter("ytime"); String mon=request.getParameter("mtime"); String num=request.getParameter("rtime"); String people = request.getParameter("people"); %> <%-- 定义SQLConn类和INSERT_SQL常量 --%> <% final String INSERT_SQL = "INSERT INTO YuYue(UserID, Time, People) VALUES (?, ?, ?)"; %> <%-- 执行数据库操作 --%> <% int count = 0; try {Connection conn = SQLConn.openDB(); PreparedStatement pstmt = conn.prepareStatement(INSERT_SQL); { pstmt.setString(1, usernum); pstmt.setString(2, name+mon+num); pstmt.setString(3, people); count = pstmt.executeUpdate(); }} catch (SQLException e) { e.printStackTrace(); } %> <%-- 根据执行结果进行相应的操作 --%> <c:choose> <c:when test="${count > 0}"> <%-- 成功跳转到ZCS.jsp --%> <c:redirect url="ZCS.jsp"/> </c:when> <c:otherwise> <%-- 失败跳转到ZCB.jsp --%> <c:redirect url="../ZCB.jsp"/> </c:otherwise> </c:choose> </body> </html>优化代码

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@ page import="java.util.*, java.sql.*"%> <%@ page import="com.util.SQLConn"%> <%@ page import="com.util.LOGS"%...

<%@ page contentType="text/html; charset=utf-8" language="java" import="java.sql." errorPage=""%> <%@ page import="com.dao.BookDAO"%> <%@ page import="com.dao.BookTypeDAO"%> <%@ page import="com.actionForm.BookForm"%> <%@ page import="com.actionForm.BookTypeForm"%> <%@ page import="com.dao.BookCaseDAO"%> <%@ page import="com.actionForm.BookCaseForm"%> <%@ page import="com.dao.PublishingDAO"%> <%@ page import="com.actionForm.PublishingForm"%> <%@ page import="java.util."%> <html> <% String str = null; BookTypeDAO bookTypeDAO = new BookTypeDAO(); Collection coll_type = (Collection) bookTypeDAO.query(str); if (coll_type == null || coll_type.isEmpty()) { out.println("<script>alert('请先录入图书类型信息!');history.back(-1);</script>"); } else { Iterator it_type = coll_type.iterator(); int typeID = 0; String typename = ""; BookCaseDAO bookcaseDAO = new BookCaseDAO(); String str1 = null; Collection coll_bookcase = (Collection) bookcaseDAO.query(str1); if (coll_bookcase == null || coll_bookcase.isEmpty()) { out.println("<script>alert('请先录入书架信息!');history.back(-1);</script>"); } else { Iterator it_bookcase = coll_bookcase.iterator(); int bookcaseID = 0; String bookcasename = ""; PublishingDAO pubDAO = new PublishingDAO(); String str2 = null; Collection coll_pub = (Collection) pubDAO.query(str2); if (coll_pub == null || coll_pub.isEmpty()) { out.println("<script>alert('请先录入出版社信息!');history.back(-1);</script>"); } else { Iterator it_pub = coll_pub.iterator(); String isbn = ""; String pubname = ""; %> <script language="jscript"> function check(form){ if(form.barcode.value==""){ alert("请输入条形码!");form.barcode.focus();return false; } if(form.bookName.value==""){ alert("请输入图书名称!");form.bookName.focus();return false; } if(form.price.value==""){ alert("请输入图书定价!");form.price.focus();return false; } } </script>

这段代码是一个 JSP 页面，用于添加图书信息。在页面中，首先通过 BookTypeDAO、BookCaseDAO 和 PublishingDAO 查询图书类型、书架和出版社信息。如果这些信息为空，会通过 JavaScript 弹窗提示用户先录入相关信息。...

<%@ page language="java" contentType="text/htm1; charset=GB1863日" pageEncoding="GB1893日" isThreadsafe="false™ import=" java.sql.,dp1. web., java.util.*"这是干什么的

其中，"contentType"指定了响应的MIME类型为"text/html"，"pageEncoding"指定了页面的字符编码格式为"GB1893日"，"isThreadsafe"指示页面是否是线程安全的，"import"用于导入需要使用的Java类和库，这里包括了SQL、...

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@ page import = "java.sql." %> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>数据处理页面</title> </head> <body> <% String userName = new String(request.getParameter("userName").getBytes("ISO-8859-1"),"UTF-8"); String password = new String(request.getParameter("password").getBytes("ISO-8859-1"),"UTF-8"); Statement st = null; Connection con = null; ResultSet rs = null; if(userName.equals("")){ response.sendRedirect("login.jsp"); } try{ Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver"); String url = "jdbc:sqlserver://localhost:1433;DatabaseName=eims;"; con = DriverManager.getConnection(url, "sa", "2017212027"); st = con.createStatement(); String sql = "select from sqlUser where userName = '"+userName+"'"; rs = st.executeQuery(sql); if(rs.next()){ String sql1 = "select * from sqlUser where password = '"+password+"'"; rs = st.executeQuery(sql1); if(rs.next()){ response.sendRedirect("main/main.jsp"); }else{ response.sendRedirect("login.jsp"); } } }catch(Exception e){ e.printStackTrace(); }finally{ rs.close(); st.close(); con.close(); } %> </body> </html>

这是因为浏览器默认使用ISO-8859-1编码方式，而在处理中文字符时需要使用UTF-8编码方式。此外，代码使用了JDBC技术连接数据库，并执行了SQL语句。需要注意的是，代码中没有对SQL注入进行处理，存在安全风险。建议...

这个代码为什么报错<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8" %> <%@ page import="java.sql.*" %> <!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>修改密码</title> </head> <body> <% // 获取表单参数 String sno = request.getParameter("sno"); String oldPassword = request.getParameter("oldPassword"); String newPassword = request.getParameter("newPassword"); String confirmPassword = request.getParameter("confirmPassword"); // 验证新密码是否一致 if (!newPassword.equals(confirmPassword)) { out.println("新密码和确认密码不一致！"); return; } // 获取当前登录用户的信息 String sno = (String) session.getAttribute("sno"); try { // 创建数据库连接 Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver"); String url = "jdbc:sqlserver://127.0.0.1:1433;DatabaseName=CJ"; String username = "sa"; String password = "Sa123456"; Connection conn = DriverManager.getConnection(url, username, password); // 查询当前用户的密码 PreparedStatement pstmt = conn.prepareStatement("SELECT Password FROM Admin2 WHERE sno = ?"); pstmt.setString(1, sno); ResultSet rs = pstmt.executeQuery(); rs.next(); String dbPassword = rs.getString("Password"); // 验证原密码是否正确 if (!dbPassword.equals(oldPassword)) { out.println("原密码不正确！"); return; } // 更新用户密码 pstmt = conn.prepareStatement("update Admin2 set Password = ? WHERE sno = ?"); pstmt.setString(1, newPassword); pstmt.setString(2, sno); pstmt.executeUpdate(); out.println("密码修改成功！"); // 关闭数据库连接 rs.close(); pstmt.close(); conn.close(); } catch (Exception e) { out.println("数据库操作出现异常：" + e.getMessage()); } %> </body> </html>

<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8" %> <%@ page import="java.sql.*" %> <!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>修改密码</title> ...

以下代码为什么页面只能出现背景图片，不能出现用户名和密码的插入<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%> <%@ page import="java.sql.*" %> <!DOCTYPE html> <html> <head> <title>注册</title> </head> <body background="3.jpg" style=" background-repeat:no-repeat ; background-size:100% 100%; background-attachment: fixed;"> <% String username = request.getParameter("username"); String password = request.getParameter("password"); String confirm_password = request.getParameter("confirm_password"); Connection conn = null; PreparedStatement ps = null; try { Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver"); conn = DriverManager.getConnection("jdbc:sqlserver://127.0.0.1:1433;database=CJ;user=sa;password=Sa123456;encrypt=false;"); String sql = "insert into Admin2(username, password) values(?, ?)"; ps = conn.prepareStatement(sql); ps.setString(1, username); ps.setString(2, password); if (password.equals(confirm_password)) { ps.executeUpdate(); session.setAttribute("username", username); response.sendRedirect("main.jsp"); } else { out.println("两次密码不一致！"); } } catch (Exception e) { e.printStackTrace(); } finally { if (ps != null) { try { ps.close(); } catch (SQLException e) { e.printStackTrace(); } } if (conn != null) { try { conn.close(); } catch (SQLException e) { e.printStackTrace(); } } }%> </body> </html>

<input type="text" name="username" id="username"><br> <label for="password">密码：</label> <input type="password" name="password" id="password"><br> <label for="confirm_password">确认密码：</...

请修改下面的两段代码使之能运行，代码 1<body> <%request.setCharacterEncoding("utf-8");//解决提交乱码问题 %> <% String stuno = request.getParameter("stuno"); String stuname = request.getParameter("stuname"); if (stuno != null) { Class.forName("com.mysql.cj.jdbc.Driver"); Connection conn = DriverManager.getConnection("jdbc:mysql: //127.0.0.1:3306/sys", "root", "1234"); PreparedStatement ps = null; ResultSet rs = null; String sql = "SELECT num FROM tb_student WHERE NUM=?"; ps = conn.prepareStatement(sql); ps.setString(1, stuno); rs = ps.executeQuery(); if (rs.next()) { out.println("对不起，该学生学号已经存在！"); } else { sql = "INSERT INTO tb_student(NUM,NAME) VALUES(?,?)"; ps = conn.prepareStatement(sql); ps.setString(1, stuno); ps.executeUpdate(); out.println("添加成功！"); } } %> 添加学生信息
<form method="post"> 输入学号:<input type="text" name="stuno">
输入姓名:<input type="text" name="stuname">
<input type="submit" value="添加"> </form> </body> </html>，代码2 // 添加学生信息到数据中 public int addStudent(Student student) throws Exception { initConnection(); // 创建一个sql语句 String sql = "insert into tb_student(num,name) values (?,?)"; // 创建一个PreparedStatement对象 PreparedStatement ps = conn.prepareStatement(sql); // 填充参数 ps.setString(1, student.getNum()); ps.setString(2, student.getName()); // 执行sql语句 int retv = ps.executeUpdate(); ps.close(); // 关闭链接 closeConnection(); return retv; }

<%@ page import="java.sql.*" %> <!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>添加学生信息</title> </head> <body> <% request.setCharacterEncoding("utf-8");//解决提交乱码问题 String ...

商品Id:<input type="text" name="pid" placeholder="商品ID可以不输入"> 前端输入商品ID后通过数据库product表精确查询，将查询到的商品id、商品图片、商品价格展示在前端jsp页面的代码

<%@ page import="java.sql.*" %> <%@ page import="com.example.Product" %> <!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>商品查询结果</title> </head> <body> <h1>商品查询结果</h1> <% ...

编写程序,实现对数据库StudentInfo中的表student进行插入操作.要求使用预处理语句对象PreparedStatement完成以下数据的插入: insert into student values('001','张三',18,'女') 注:给定数据库登录用户名:sa,密码:123. Input.jsp: 请输入待新增的学生信息学号: 姓名: 年龄: 性别: addStudent.jsp: <% String url="jdbc:sqlserver://localhost;databaseName=StudentInfo"; request.setCharacterEncoding("utf-8"); String sno = request.getParameter("sno"); String sname = request.getParameter("sname"); int sage = Integer.valueOf(request.getParameter("sage")); String sex = request.getParameter("sex"); try{ //补全此部分代码 } // 捕获异常 catch(SQLException ex) { System.out.println ("\n* 发生SQL异常 *\n"+ex.getMessage()); } catch(ClassNotFoundException ex) { System.out.println(ex); }

<%@ page import="java.sql.*" %> <!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>Insert Student</title> </head> <body> <% String url="jdbc:sqlserver://localhost;databaseName=StudentInfo"; ...

<%@ page language- 'java" import= "java.util.,_ 1_ .jvax.sql. " contentType-" text/html;charset=GBK"%><html> <body> <%Connection con-null; 2)_st=null; int counter=0; Savepoint p=null,p0= null,p1=null; try { Class.forName("com._ 3)_ .cj.jdbc.Driver"); String url= "jdbc:mาysq.:/lcalhost3306/student?_ 4_ =Asia/Shanghai&user-root&password-123456"con=DriverManager._ (5)_ (url); String sql="insert into student(id,username, chinesecent,mathcent) value(?,?,?,?)"; st=con.prepareStatement(_ _6)_ ); con. setAutoCommit{_ 7_ _); p0=con.setSavepoint("1"); counter=1; st.setString(1."777"); st.setString(2."Wang"); st. setFloat(3,"85"); st.setFloat(4,"90");. st.executeUpdate(); p1-con.setSavepoint("2"); counter-=2; st. setstrin(.112233445566777"); st. setString(2,"Zhang"); st. setFloat(3,"80"); st. .setFloat(4,"85 '); st.executeUpdate(); con._ _(8_ ();. out. println("成功加入成绩记录，请验证"); } catch(Exception e out.println("出错： "+e); out. println("
回滚事务"); switch(counter) { case 1: con.rollback(_ 9_ ); break; case 2: con.rollback(p1); break; default: con.rollback(); } } finally { if(st!=null) st.close(); } if(con!=null) { con.setAutoCommit(true); con.close(); } } </body> </html> 阅读上述带事务处理的JDBC编程程序，分析程序最终执行的结果是成功加入（10）条学生记录，请补充填写1-10处内容

6. 应该填写sql 7. 应该填写false 8. 应该填写commit() 9. 应该填写p0 10. 成功加入2条学生记录。程序执行时，第一条记录成功插入，第二条记录插入时出错，触发了异常，执行了回滚操作，因此只有第一条记录...

<input type="number" id="quantity" name="quantity" min="1" max="10" value="1"> <button class="add-to-cart" data-product-id="0001" data-product-quantity="quantity">加入购物车</button>如何获取数量点击后用jsp获取ID和数量值

<%@ page import="java.io.*,java.util.*,java.sql.*"%> <% // 获取表单提交的商品ID和数量值 String productId = request.getParameter("productId"); String quantity = request.getParameter("quantity"); ...

用java，jsp，数据库，html写一个学生列表页面list.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@ page import="java.sql.*" %> <!DOCTYPE html> <html> <head> <title>学生列表</title> </head> <body> <h1>学生...

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<input type="number" id="quantity" name="quantity" min="1" max="10" value="1"> <button class="add-to-cart" data-product-id="0001" data-product-quantity="quantity">加入购物车</button>如何获取数量点击后用jsp获取ID和数量值

用java，jsp，数据库，html写一个学生列表页面list.jsp

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<%@ page language="java" contentType="text/htm1; charset=GB1863日" pageEncoding="GB1893日" isThreadsafe="false™ import=" java.sql.,dp1. web., java.util.*"这是干什么的