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 <br> <form method="post"> 输入学号:<input type="text" name="stuno"><BR> 输入姓名:<input type="text" name="stuname"><BR> <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; }

时间: 2024-03-26 16:34:51 浏览: 87

代码1修改后的代码如下： ```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>添加学生信息</title> </head> <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?useUnicode=true&characterEncoding=utf-8&useSSL=false", "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.setString(2, stuname); ps.executeUpdate(); out.println("添加成功！"); } rs.close(); ps.close(); conn.close(); } %> 添加学生信息 <br> <form method="post"> 输入学号:<input type="text" name="stuno"><BR> 输入姓名:<input type="text" name="stuname"><BR> <input type="submit" value="添加"> </form> </body> </html> ``` 代码2修改后的代码如下： ```java // 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; } ```

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