diff --git "a/09 \346\241\202\346\263\275\347\205\234/2023-05-24\344\275\234\344\270\232.md" "b/09 \346\241\202\346\263\275\347\205\234/2023-05-24\344\275\234\344\270\232.md" new file mode 100644 index 0000000000000000000000000000000000000000..53a67151082083b4ca3aa4824c66940cbd38cc72 --- /dev/null +++ "b/09 \346\241\202\346\263\275\347\205\234/2023-05-24\344\275\234\344\270\232.md" @@ -0,0 +1,251 @@ +```html + + + + + 学生管理系统 + + +
+

查询学生

+ 输入你要查询的学生编号:
+ 输入你要查询的学生姓名:
+ 输入你要查询的学生性别:
+ +
+
+

添加学生

+ 输入你要添加的学生编号:
+ 输入你要添加的学生姓名:
+ 输入你要添加的学生性别:
+ +
+
+

删除学生

+ 输入你要删除的学生编号:
+ +
+
+

修改学生

+ 输入你要修改的学生编号:
+ 输入你要修改的学生姓名:
+ +
+ + +``` + +```java +package com.dao; + +import java.sql.*; + +public class Dao { + private Connection conn; + private String driver = "com.mysql.jdbc.Driver"; + private String url ="jdbc:mysql://localhost:3306/student_db?useSSL=false&useUnicode=true&charsetEnding=utf8"; + private String user="root"; + private String password="root"; + + public Dao() { + try { + Class.forName(driver); + System.out.println("驱动加载成功"); + } catch (ClassNotFoundException e) { + System.out.println("驱动加载失败!"); + throw new RuntimeException(e); + } + } + + public Connection getConn() { + try { + conn = DriverManager.getConnection(url,user,password); + System.out.println("数据库连接成功"); + } catch (SQLException e) { + System.out.println("数据库连接失败！"); + throw new RuntimeException(e); + } + return conn; + } + + public void setConn(Connection conn) { + this.conn = conn; + } +} + +``` + +```java +package com.student; + +public class Student { + private int id; + private String name; + private String sex; + + public Student() { + } + + public Student(int id, String name, String sex) { + this.id = id; + this.name = name; + this.sex = sex; + } + + public void setId(int id) { + this.id = id; + } + + + public void setName(String name) { + this.name = name; + } + + public void setSex(String sex) { + this.sex = sex; + } + + @Override + public String toString() { + return "id= "+ id +" name= "+name+" sex= "+sex; + } +} + +``` + +```java +package com.servlet; + +import com.dao.Dao; +import com.student.Student; + +import javax.servlet.*; +import javax.servlet.http.*; +import javax.servlet.annotation.*; +import java.io.IOException; +import java.sql.PreparedStatement; +import java.sql.ResultSet; +import java.sql.SQLException; + +@WebServlet(name = "Servlet", value = "/Servlet") +public class Servlet extends HttpServlet { + @Override + protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { + response.setContentType("text/html;charset=utf-8"); + request.setCharacterEncoding("utf-8"); + System.out.println("你调用了get方法"); + String mess = request.getParameter("submit"); + if (mess.endsWith("查询")) { + Find(request, response); + } + if (mess.endsWith("添加")) { + Add(request, response); + } + if (mess.endsWith("删除")) { + Delete(request, response); + } + if(mess.endsWith("修改")){ + Update(request,response); + } + } + + //查询 + public void Find(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { + String id = request.getParameter("id"); + String name = request.getParameter("name"); + String sex = request.getParameter("sex"); + Student st = new Student(); + Dao dao = new Dao(); + String sql = "select * from student where id=? and name=? and sex=?"; + try { + PreparedStatement pre = dao.getConn().prepareStatement(sql); + pre.setString(1, id); + pre.setString(2, name); + pre.setString(3, sex); + ResultSet res = pre.executeQuery(); + while (res.next()) { + id = res.getString("id"); + name = res.getString("name"); + sex = res.getString("sex"); + st.setId(Integer.parseInt(id)); + st.setName(name); + st.setSex(sex); + response.getWriter().write(String.valueOf(st)); + } + res.close(); + } catch (SQLException e) { + } + } + + //添加 + public void Add(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { + String id = request.getParameter("id"); + String name = request.getParameter("name"); + String sex = request.getParameter("sex"); + Student st = new Student(); + Dao dao = new Dao(); + String sql = "insert into student values(?,?,?)"; + try { + PreparedStatement pre = dao.getConn().prepareStatement(sql); + pre.setString(1, id); + pre.setString(2, name); + pre.setString(3, sex); + int i = pre.executeUpdate(); + if (i > 0) { + st.setId(Integer.parseInt(id)); + st.setName(name); + st.setSex(sex); + System.out.println(st); + response.getWriter().write("添加成功"); + } else response.getWriter().write("添加失败"); + pre.close(); + } catch (SQLException e) { + } + } +//删除 + public void Delete(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { + String id = request.getParameter("id"); + Student st = new Student(); + Dao dao = new Dao(); + String sql = "delete from student where id=?"; + try { + PreparedStatement pre = dao.getConn().prepareStatement(sql); + pre.setString(1, id); + int i = pre.executeUpdate(); + if (i > 0) { + st.setId(Integer.parseInt(id)); + response.getWriter().write("删除成功"); + } else response.getWriter().write("删除失败"); + pre.close(); + } catch (SQLException e) { + } + } + //修改 +public void Update(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { + String id = request.getParameter("id"); + String name = request.getParameter("name"); + Student st = new Student(); + Dao dao = new Dao(); + String sql = "update student set name=? where id=?"; + try { + PreparedStatement pre = dao.getConn().prepareStatement(sql); + pre.setString(2, id); + pre.setString(1,name); + int i = pre.executeUpdate(); + if (i > 0) { + st.setId(Integer.parseInt(id)); + st.setName(name); + response.getWriter().write("修改成功"); + } else response.getWriter().write("修改失败"); + pre.close(); + } catch (SQLException e) { + } +} + @Override + protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { + doGet(request, response); + } +} + +``` +