diff --git "a/24 \351\231\210\344\277\212\345\223\262/20230523\344\275\234\344\270\232.md" "b/24 \351\231\210\344\277\212\345\223\262/20230523\344\275\234\344\270\232.md" deleted file mode 100644 index 6da1d27ed91a3929a50529e1eaca83170d16f670..0000000000000000000000000000000000000000 --- "a/24 \351\231\210\344\277\212\345\223\262/20230523\344\275\234\344\270\232.md" +++ /dev/null @@ -1,195 +0,0 @@ -````java -# 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？ - -``` - -工具类 - -```java -import java.sql.*; -public class DbJbdc { - 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.cj.jdbc.Driver"); - Connection conn = DriverManager.getConnection(url, user, pass); - return conn; - } - public static int currencyUpdate(String sql,String ...flop) throws SQLException, ClassNotFoundException { - Connection conn = link(); - PreparedStatement prs = conn.prepareStatement(sql); - for (int i = 0; i < flop.length; i++) { - prs.setString((i+1),flop[i]); - } - int i = prs.executeUpdate(); - return i; - } - public static int delete(String sql,String ...flop) throws SQLException, ClassNotFoundException { - int i = currencyUpdate(sql, flop); - return i; - } - public static int modify(String sql,String ...flop) throws SQLException, ClassNotFoundException { - int i = currencyUpdate(sql, flop); - return i; - } - public static int add(String sql,String ...flop) throws SQLException, ClassNotFoundException { - int i = currencyUpdate(sql, flop); - return i; - } - public static ResultSet Query(String sql,String ...flop) throws SQLException, ClassNotFoundException { - Connection conn = link(); - PreparedStatement prs = conn.prepareStatement(sql); - for (int i = 0; i < flop.length; i++) { - prs.setString((i+1),flop[i]); - } - ResultSet rs = prs.executeQuery(); - return rs; - } -} -``` - -```java -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.ResultSet; -import java.sql.SQLException; -@WebServlet("/seek") -public class Seek extends HttpServlet { - @Override - protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { - resp.setContentType("text/html;charset=utf-8"); - resp.setCharacterEncoding("utf-8"); - try { - String sql ="select * from student"; - ResultSet rs = DbJbdc.Query(sql); - while (rs.next()){ - int id = rs.getInt("id"); - String name = rs.getString("name"); - String sex = rs.getString("sex"); - resp.getWriter().write(id+" "+name+" "+sex+"
"); - } - } catch (SQLException e) { - e.printStackTrace(); - } catch (ClassNotFoundException e) { - e.printStackTrace(); - } - } - - @Override - protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { - super.doPost(req, resp); - } -} ------------------------------------------------------------ -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.SQLException; -@WebServlet("/add") -public class Add extends HttpServlet { - @Override - protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { - resp.setContentType("text/html;charset=utf-8"); - resp.setCharacterEncoding("utf-8"); - try { - String sql ="insert into student values (?,?,?)"; - int add = DbJbdc.add(sql, "0", "小明", "男"); - if (add>0){ - resp.getWriter().write("成功"); - }else { - resp.getWriter().write("失败"); - } - } catch (SQLException e) { - throw new RuntimeException(e); - } catch (ClassNotFoundException e) { - throw new RuntimeException(e); - } - } - - @Override - protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { - super.doPost(req, resp); - } -} ------------------------------------------------------------- -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.SQLException; -@WebServlet("/delete") -public class Delete extends HttpServlet { - @Override - protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { - resp.setContentType("text/html;charset=utf-8"); - resp.setCharacterEncoding("utf-8"); - try { - String sql ="delete from student where id=?"; - int add = DbJbdc.add(sql, "1"); - if (add>0){ - resp.getWriter().write("成功"); - }else { - resp.getWriter().write("失败"); - } - } catch (SQLException e) { - throw new RuntimeException(e); - } catch (ClassNotFoundException e) { - throw new RuntimeException(e); - } - } - - @Override - protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { - super.doPost(req, resp); - } -} ------------------------------------------------------------- -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.SQLException; -@WebServlet("/modify") -public class Modify extends HttpServlet { - @Override - protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { - resp.setContentType("text/html;charset=utf-8"); - resp.setCharacterEncoding("utf-8"); - try { - String sql ="update student set sex=? where id=?"; - int add = DbJbdc.add(sql, "女","2"); - if (add>0){ - resp.getWriter().write("成功"); - }else { - resp.getWriter().write("失败"); - } - } catch (SQLException e) { - throw new RuntimeException(e); - } catch (ClassNotFoundException e) { - throw new RuntimeException(e); - } - } - - @Override - protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { - super.doPost(req, resp); - } -} -```` - diff --git "a/24 \351\231\210\344\277\212\345\223\262/20230527 \344\275\234\344\270\232.md" "b/24 \351\231\210\344\277\212\345\223\262/20230527 \344\275\234\344\270\232.md" new file mode 100644 index 0000000000000000000000000000000000000000..0fc500eb79dfabafb7e0143cf59f91b52102cd5f --- /dev/null +++ "b/24 \351\231\210\344\277\212\345\223\262/20230527 \344\275\234\344\270\232.md" @@ -0,0 +1,164 @@ +# 作业 + +```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"); + } + } +} +``` +