diff --git "a/07 \345\206\257\345\273\272\347\250\213/20230519 jdbc\344\275\234\344\270\232.md.txt" "b/07 \345\206\257\345\273\272\347\250\213/20230519 jdbc\344\275\234\344\270\232.md" similarity index 100% rename from "07 \345\206\257\345\273\272\347\250\213/20230519 jdbc\344\275\234\344\270\232.md.txt" rename to "07 \345\206\257\345\273\272\347\250\213/20230519 jdbc\344\275\234\344\270\232.md" diff --git "a/07 \345\206\257\345\273\272\347\250\213/20230520 \344\275\234\344\270\232.md.txt" "b/07 \345\206\257\345\273\272\347\250\213/20230520 \344\275\234\344\270\232.md" similarity index 100% rename from "07 \345\206\257\345\273\272\347\250\213/20230520 \344\275\234\344\270\232.md.txt" rename to "07 \345\206\257\345\273\272\347\250\213/20230520 \344\275\234\344\270\232.md" diff --git "a/07 \345\206\257\345\273\272\347\250\213/20230522 \344\275\234\344\270\232.txt" "b/07 \345\206\257\345\273\272\347\250\213/20230522 \344\275\234\344\270\232.md" similarity index 100% rename from "07 \345\206\257\345\273\272\347\250\213/20230522 \344\275\234\344\270\232.txt" rename to "07 \345\206\257\345\273\272\347\250\213/20230522 \344\275\234\344\270\232.md" diff --git "a/07 \345\206\257\345\273\272\347\250\213/20230524 \344\275\234\344\270\232.md" "b/07 \345\206\257\345\273\272\347\250\213/20230524 \344\275\234\344\270\232.md" new file mode 100644 index 0000000000000000000000000000000000000000..7d5d60da207e9c88caa970cc39af3969b4d67d76 --- /dev/null +++ "b/07 \345\206\257\345\273\272\347\250\213/20230524 \344\275\234\344\270\232.md" @@ -0,0 +1,217 @@ +```html + + + + + + Title + + +
+ ID + +
+
+
+ ID + name + +
+
+
+ ID + +
+
+
+ ID + newName + +
+ + +``` + +```java +//查询 +import jakarta.servlet.*; +import jakarta.servlet.http.*; +import jakarta.servlet.annotation.*; + +import java.io.IOException; +import java.sql.ResultSet; +import java.sql.SQLException; + +@WebServlet(name = "select", value = "/select") +public class select extends HttpServlet { + @Override + protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { + + } + + @Override + protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { + response.setCharacterEncoding("utf-8"); + response.setContentType("text/html;charset=utf-8"); + String id1 = request.getParameter("id"); + ResultSet re = Jdbc.select("select * from student where id=?", id1); + try { + while (re.next()) { + String id = re.getString(1); + String name = re.getString(2); + response.getWriter().write(id+" "+name+"
"); + } + } catch (SQLException e) { + throw new RuntimeException(e); + } + } +} +``` + +```java +//添加 +import jakarta.servlet.*; +import jakarta.servlet.http.*; +import jakarta.servlet.annotation.*; + +import java.io.IOException; + +@WebServlet(name = "add", value = "/add") +public class add extends HttpServlet { + @Override + protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { + + } + + @Override + protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { + response.setCharacterEncoding("utf-8"); + response.setContentType("text/html;charset=utf-8"); + String id = request.getParameter("id"); + String name = request.getParameter("name"); + int i = Jdbc.update("insert into student values(?,?)",id,name); + if (i>0){ + response.getWriter().write("添加成功"); + }else { + response.getWriter().write("添加失败"); + } + } +} +``` + +```java +//删除 +import jakarta.servlet.*; +import jakarta.servlet.http.*; +import jakarta.servlet.annotation.*; + +import java.io.IOException; + +@WebServlet(name = "delete", value = "/delete") +public class delete extends HttpServlet { + @Override + protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { + + } + + @Override + protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { + response.setCharacterEncoding("utf-8"); + response.setContentType("text/html;charset=utf-8"); + String id = request.getParameter("id"); + int i = Jdbc.update("delete from student where id=?",id); + if (i>0){ + response.getWriter().write("删除成功"); + }else { + response.getWriter().write("删除失败"); + } + } +} +``` + +```java +//修改 +import jakarta.servlet.*; +import jakarta.servlet.http.*; +import jakarta.servlet.annotation.*; + +import java.io.IOException; + +@WebServlet(name = "update", value = "/update") +public class update extends HttpServlet { + @Override + protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { + + } + + @Override + protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { + response.setCharacterEncoding("utf-8"); + response.setContentType("text/html;charset=utf-8"); + String id = request.getParameter("id"); + String name = request.getParameter("name"); + int i = Jdbc.update("update student set name=? where id=?",name,id); + if (i>0){ + response.getWriter().write("修改成功"); + }else { + response.getWriter().write("修改失败"); + } + } +} +``` + +```java +//工具类 +import java.sql.*; + +public class Jdbc { + static { + try { + Class.forName("com.mysql.jdbc.Driver"); + } catch (ClassNotFoundException e) { + throw new RuntimeException(e); + } + } + + //创建连接 + private static Connection conn() { + String url = "jdbc:mysql://localhost:3306/text?useSSL=false&useUnicode=true&characterEncoding=utf8"; + Connection conn = null; + try { + conn = DriverManager.getConnection(url, "root", "root"); + } catch (SQLException e) { + throw new RuntimeException(e); + } + return conn; + } + + //查询 + public static ResultSet select(String sql, String... arr) { + ResultSet re = null; + try { + PreparedStatement pst = conn().prepareStatement(sql); + for (int i = 0; i < arr.length; i++) { + pst.setString((i + 1), arr[i]); + } + re = pst.executeQuery(); + } catch (SQLException e) { + throw new RuntimeException(e); + } + return re; + } + + //增删改 + public static int update(String sql, String... arr) { + try { + PreparedStatement pst = conn().prepareStatement(sql); + for (int i = 0; i < arr.length; i++) { + pst.setString((i + 1), arr[i]); + } + int i = pst.executeUpdate(); + return i; + } catch (SQLException e) { + throw new RuntimeException(e); + } + } +} +``` \ No newline at end of file