From 1301b5c58d192931b0827a751f8fb52463d16bba Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E5=BC=A0=E9=BE=99=E8=85=BE?= <2235304668@qq.com> Date: Tue, 23 May 2023 22:08:07 +0800 Subject: [PATCH] =?UTF-8?q?servlet=E4=BD=9C=E4=B8=9A?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- ...230523 Servlet\344\275\234\344\270\232.md" | 219 ++++++++++++++++++ 1 file changed, 219 insertions(+) create mode 100644 "22 \345\274\240\351\276\231\350\205\276/20230523 Servlet\344\275\234\344\270\232.md" diff --git "a/22 \345\274\240\351\276\231\350\205\276/20230523 Servlet\344\275\234\344\270\232.md" "b/22 \345\274\240\351\276\231\350\205\276/20230523 Servlet\344\275\234\344\270\232.md" new file mode 100644 index 0000000..c4f8f59 --- /dev/null +++ "b/22 \345\274\240\351\276\231\350\205\276/20230523 Servlet\344\275\234\344\270\232.md" @@ -0,0 +1,219 @@ +~~~java +package servlet; + +//工具类 + +import java.sql.*; + +public class BUilt { + private static final String url = "jdbc:mysql:///student_db?useSSL=false&useUnicode=true&characterEncoding=utf8"; + private static final String user = "root"; + private static final String pass = "root"; + + public static Connection link() throws ClassNotFoundException, SQLException { + Class.forName("com.mysql.jdbc.Driver"); + Connection conn = DriverManager.getConnection(url, user, pass); + return conn; + } + + public static int currencyUpdate(String sql, String... keys) throws SQLException, ClassNotFoundException { + Connection conn = link(); + PreparedStatement prs = conn.prepareStatement(sql); + for (int i = 0; i < keys.length; i++) { + prs.setString((i + 1), keys[i]); + } + int i = prs.executeUpdate(); + return i; + } + + public static int delete(String sql, String... keys) throws SQLException, ClassNotFoundException { + int i = currencyUpdate(sql, keys); + return i; + } + + public static int update(String sql, String... keys) throws SQLException, ClassNotFoundException { + int i = currencyUpdate(sql, keys); + return i; + } + + public static int add(String sql, String... keys) throws SQLException, ClassNotFoundException { + int i = currencyUpdate(sql, keys); + return i; + } + + public static ResultSet Query(String sql, String... keys) throws SQLException, ClassNotFoundException { + Connection conn = link(); + PreparedStatement prs = conn.prepareStatement(sql); + for (int i = 0; i < keys.length; i++) { + prs.setString((i + 1), keys[i]); + } + ResultSet rs = prs.executeQuery(); + return rs; + } +} + +~~~ + + + +~~~java +package servlet; + +import javax.servlet.ServletException; +import javax.servlet.annotation.WebServlet; +import javax.servlet.http.HttpServlet; +import javax.servlet.http.HttpServletRequest; +import javax.servlet.http.HttpServletResponse; +import java.io.IOException; +import java.sql.*; + +@WebServlet("/Servlet/Add") +public class StudentServlet extends HttpServlet { + + // # 作业， +// * 1 数据库相关的操作，使用封装的工具类 +// * 2 编写四个servlet，使用注解指定相关的访问路径，分别对应查询，修改，删除，添加的操作 +// * 3 从浏览器中，访问这中个路径，显示响应的信息，查询显示结果，其它的显示成功或是失败 +// * 4 预习题：如何通过浏览器传送请求参数给servlet，servlet如何接收这些参数，并使用这些参数，去影响数据库的操作？ + @Override + protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { + resp.setContentType("text/html;charset=utf-8");// 设置网页的格式 + resp.setCharacterEncoding("utf-8");// 设置网页的编码 + resp.getWriter().write("这是增加的操作" + "
"); + // 在这里写java代码 + try { + Class.forName("com.mysql.jdbc.Driver"); + Connection conn = DriverManager.getConnection("jdbc:mysql:///student?useSSL=false&useUnicode=true&characterEncoding=utf8", "root", "root"); + String ADD = "insert into student values (?,'?','?')"; + PreparedStatement pst = conn.prepareStatement(ADD); + int add = BUilt.add("sql", "0", "小明", "男"); + int re = pst.executeUpdate(); + if (re > 0) { + resp.getWriter().write("添加成功,添加了" + re + "行" + "
"); + } else { + resp.getWriter().write("添加失败!" + "
"); + } + + + } catch (ClassNotFoundException e) { + throw new RuntimeException(e); + } catch (SQLException e) { + throw new RuntimeException(e); + } + + } + + @Override + protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { + super.doPost(req, resp); + } + +} + +@WebServlet("/Servlet/Delete") +class Delete extends HttpServlet { + @Override + protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { + resp.setContentType("text/html;charset=utf-8");// 设置网页的格式 + resp.setCharacterEncoding("utf-8");// 设置网页的编码 + resp.getWriter().write("这是删除的操作"); + try { + Class.forName("com.mysql.jdbc.Driver"); + Connection conn = DriverManager.getConnection("jdbc:mysql:///student?useSSL=false&useUnicode=true&characterEncoding=utf8", "root", "root"); + String Delete = "delete from student where id=?"; + int delete = BUilt.delete("sql", "1"); + + if (delete > 0) { + resp.getWriter().write("删除成功,删除了" + delete + "行" + "
"); + } else { + resp.getWriter().write("删除失败!" + "
"); + } + + + } catch (ClassNotFoundException e) { + throw new RuntimeException(e); + } catch (SQLException e) { + throw new RuntimeException(e); + } + } + + @Override + protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { + super.doPost(req, resp); + } +} + + +@WebServlet("/Servlet/Update") +class Update extends HttpServlet { + @Override + protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { + resp.setContentType("text/html;charset=utf-8");// 设置网页的格式 + resp.setCharacterEncoding("utf-8");// 设置网页的编码 + resp.getWriter().write("这是更新的操作"); + try { + Class.forName("com.mysql.jdbc.Driver"); + Connection conn = DriverManager.getConnection("jdbc:mysql:///student?useSSL=false&useUnicode=true&characterEncoding=utf8", "root", "root"); + String Delete = "update student set sex=? where id=?"; + int update = BUilt.update("sql", "男", "5"); + + if (update > 0) { + resp.getWriter().write("更新成功,删除了" + update + "行" + "
"); + } else { + resp.getWriter().write("删除失败!" + "
"); + } + + + } catch (ClassNotFoundException e) { + throw new RuntimeException(e); + } catch (SQLException e) { + throw new RuntimeException(e); + } + } + + @Override + protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { + super.doPost(req, resp); + } +} + + +@WebServlet("/Servlet/Quire") +class Quire extends HttpServlet { + @Override + protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { + resp.setContentType("text/html;charset=utf-8");// 设置网页的格式 + resp.setCharacterEncoding("utf-8");// 设置网页的编码 + resp.getWriter().write("这是查询的操作" + "
"); + // 在这里写java代码 + try { + Class.forName("com.mysql.jdbc.Driver"); + Connection conn = DriverManager.getConnection("jdbc:mysql:///student?useSSL=false&useUnicode=true&characterEncoding=utf8", "root", "root"); + String sql = "select *from student"; + PreparedStatement pst = conn.prepareStatement(sql); + ResultSet re = pst.executeQuery(); + + while (re.next()) { + int id = re.getInt("id"); + String name = re.getString("name"); + String sex = re.getString("sex"); + System.out.println(id + name + sex); + + resp.getWriter().write("ID:" + id + " 姓名:" + name + " 性别:" + sex + "
"); + } + } catch (ClassNotFoundException e) { + throw new RuntimeException(e); + } catch (SQLException e) { + throw new RuntimeException(e); + } + + } + + @Override + protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { + super.doPost(req, resp); + } +} + +~~~ + -- Gitee