JavaWeb实现增删查改(图书信息管理)之删除功能实现

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　　　　删除按钮对应的servlet -->DeleteBooks.java  ↓

 package BookSystem.CRUD;
 import BookSystem.Other.DButil;

 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.Connection;
 import java.sql.PreparedStatement;
 import java.sql.SQLException;

 @WebServlet("/books/del")
 public class DeleteBooks extends HttpServlet {
     @Override
     protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
         //获取id
         int id=Integer.parseInt(req.getParameter("id"));
         Connection connection=null;
         PreparedStatement prsmt=null;
         String sql;
         try {
             //获取连接
             connection=new DButil().getConnection();
             //判断：如果获取一个id 就按id对应的数据删除，否则删除全部
             if(id==-1){
                 sql="delete from BookInfo ";

             }else {
                 sql="delete from BookInfo  where book_id= "+id;
             }
             //执行sql语句
             prsmt=connection.prepareStatement(sql);
             prsmt.executeUpdate();
         }catch (SQLException e){
             e.printStackTrace();
         }finally {
             try {
                 //关闭
                 connection.close();
                 prsmt.close();
             } catch (SQLException e) {
                 e.printStackTrace();
             }

         }

         req.getRequestDispatcher("/books/lst").forward(req, resp);
     }

 }

　　　　删除按钮再index.jsp页面，如下图所示：↓

　　　　注：该整个CRUD不展示效果图，整体CSS应当有属于自己的风格~