mvc的增删改查

最新推荐文章于 2022-06-29 12:44:25 发布

CJQ余小C

最新推荐文章于 2022-06-29 12:44:25 发布

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CC 4.0 BY-SA版权

本文链接：https://blog.youkuaiyun.com/CJQYQX/article/details/97498855

1.导入jar包
在这里插入图片描述
2.所需要的类（于前面所写一样）

book实体类

package com.cjq.eneity;
public class Book {
 private int bid;
 private String bname;
 private float price; @Override
 public String toString() {
  return "Book [bid=" + bid + ", bname=" + bname + ", price=" + price + "]";
 } public int getBid() {
  return bid;
 } public void setBid(int bid) {
  this.bid = bid;
 } public String getBname() {
  return bname;
 } public void setBname(String bname) {
  this.bname = bname;
 } public float getPrice() {
  return price;
 } public void setPrice(float price) {
  this.price = price;
 }
 
 public Book() {
   super();
    }
 public Book(int bid, String bname, float price) {
  super();
  this.bid = bid;
  this.bname = bname;
  this.price = price;
 }
    
}

bookdao

package com.cjq.eneity;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.util.List;import com.cjq.util.BaseDao;
import com.cjq.util.DBAccess;
import com.cjq.util.PageBean;
import com.cjq.util.StringUtils;

public class BookDao extends BaseDao<Book> {
 //查询
public List<Book> list(Book book,PageBean pageBean) throws InstantiationException, IllegalAccessException, SQLException{
 String sql="select * from t_mvc_book where true";
 String bname=book.getBname();
 int bid = book.getBid();
 
 if(StringUtils.isNotBlank(bname)) {
  sql+=" and bname like '%"+bname+"%'";
 }
 
 if(bid!=0) {
  sql+=" and bid = "+bid;
 }
 return super.executeQuery(sql, Book.class, pageBean);
}

public int add(Book book) throws SQLException, IllegalArgumentException, IllegalAccessException {
 String sql="insert into t_mvc_book values(?,?,?)";
 return super.executeUpdate(sql, new String [] {"bid","bname","price"}, book);
}

public int edit(Book book) throws SQLException, IllegalArgumentException, IllegalAccessException {
 String sql="update t_mvc_book set bname=?,price=? where bid=?";
 return super.executeUpdate(sql, new String [] {"bname","price","bid"}, book);
}

public int del(Book book) throws SQLException, IllegalArgumentException, IllegalAccessException {
 String sql="delete from t_mvc_book where bid=?";
 return super.executeUpdate(sql, new String [] {"bid"}, book);
}

public static void main(String[] args) throws IllegalArgumentException, IllegalAccessException, SQLException {
 BookDao bookDao=new BookDao();
 Book book=new Book(141313,"xxx",56f);
 bookDao.del(book);
}
}

baseDao

package com.cjq.util;
import java.lang.reflect.Field;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
/**
 * 用来处理所有表的增删改查
 * 
 * 查询值得是：通用的分页查询
 * @author 86135
 *
 * @param <T>
 */
public class BaseDao<T>{
 /**
  * sql 可能不用的表，那么意味着Sql是获得变化的那边它是从子类再传递到父类
  * clz 需要返回不同的对象集合，Book.Class/Order.Class
  * page 可能要分页
  * @param sql
  * @param clz
  * @param page
  * @return
  * @throws SQLException
  * @throws IllegalAccessException 
  * @throws InstantiationException 
  */
// public List<T> executeQuery(String sql,Class clz,PageBean page) throws SQLException, InstantiationException, IllegalAccessException{
//  List<T> list=new ArrayList<T>();
//  Connection con=DBAccess.getConnection();
//  PreparedStatement ps = con.prepareStatement(sql);
//  ResultSet rs = ps.executeQuery();
//  T t=null;
//  while(rs.next()) {
//   //list.add(new Book(rs.getInt("bid"),rs.getString("bname"),rs.getFloat("price")));
//   /**
//    * 1.实例化了一个Book对象
//    * 2.通过book对象的属性名去游标中取出属性值
//    *  2.1获取到类对象中的属性
//    *  2.2然后给属性赋值
//    * 3.已经赋值好的book实例对象放入list集合中
//    * 
//    * clz>Book.class
//    */
//   t=(T) clz.newInstance();
//   Field[] field = clz.getDeclaredFields();
//   for (Field f : field) {
//    f.setAccessible(true);
//    f.set(t, rs.getObject(f.getName()));
//   }
//   list.add( t);
//  }
//  return list;
// }
 
 //第三
  public List<T> executeQuery(String sql,Class clz,PageBean pageBean) throws SQLException, InstantiationException, IllegalAccessException{
  List<T> list=new ArrayList<T>();
  Connection con=DBAccess.getConnection();
  PreparedStatement ps =null;
  ResultSet rs = null;
  if(pageBean!=null && pageBean.isPagination()) {
   //分页代码
   /*
    * 1.分页是与PageBean中total有关，意味着需要查询数据库得到得到total给pageBean
    * 2。查询出符合条件的某一页的数据
    * select count(*) from (select * from t_mvc_book where bname like '%圣墟%') t;
    */
   //通过原生Sql拼接出符合条件的
   String countSql=getCountSql(sql);
   ps = con.prepareStatement(countSql);
    rs=ps.executeQuery();
    if(rs.next()) {
     pageBean.setTotal(rs.getObject(1).toString());
    }
    //第二部 拼接 select * from t_mvc_book where bname like '%圣墟%'  limit 10,10;
    String pageSql=getPageSql(sql,pageBean);
    ps = con.prepareStatement(pageSql);
    rs=ps.executeQuery();
  }else {
   //不分页代码
   ps = con.prepareStatement(sql);
    rs=ps.executeQuery();
  }
  
  T t=null;
  while(rs.next()) {
   //list.add(new Book(rs.getInt("bid"),rs.getString("bname"),rs.getFloat("price")));
   /**
    * 1.实例化了一个Book对象
    * 2.通过book对象的属性名去游标中取出属性值
    *  2.1获取到类对象中的属性
    *  2.2然后给属性赋值
    * 3.已经赋值好的book实例对象放入list集合中
    * 
    * clz>Book.class
    */
   t=(T) clz.newInstance();
   Field[] field = clz.getDeclaredFields();
   for (Field f : field) {
    f.setAccessible(true);
    f.set(t, rs.getObject(f.getName()));
   }
   list.add( t);
  }
  DBAccess.close(con, ps, rs);
  return list;
 }
 private String getPageSql(String sql, PageBean pageBean) {
  return sql+" limit "+pageBean.getStartIndex()+","+pageBean.getRows();
 }
 private String getCountSql(String sql) {
  return "select count(1) from ("+sql+") t";
 }
 /**
  * 通用增删改
  * 
  * @param sql 增删改的Sql语句
  * @param t 实体类（里面包含了参数值）
  * @param attrs 代表Sql语句的问号
  * @return
  */
 public int executeUpdate(String sql,String[] attrs,T t) throws IllegalArgumentException, IllegalAccessException, SQLException {
  Connection con=DBAccess.getConnection();
     PreparedStatement pst = con.prepareStatement(sql);
     Field field=null;
     /* pst.setInt(1, book.getBid());
     pst.setString(2, book.getBname());
     pst.setFloat(3, book.getPrice()); */
     //一切反射的相关代码都是从类对象开始
     //Field[] fields = t.getClass().getDeclaredFields();
    for (int i = 0; i < attrs.length; i++) {
     try {
   field=t.getClass().getDeclaredField(attrs[i]);
    field.setAccessible(true);
           pst.setObject(i+1,field.get(t));
  } catch (NoSuchFieldException | SecurityException e) {
   e.printStackTrace();
  }
 }
    int num = pst.executeUpdate();
    DBAccess.close(con, pst, null);
  return num;
 }
}

bookAction

package com.cjq.web;

import java.sql.SQLException;
import java.util.List;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.cjq.eneity.Book;
import com.cjq.eneity.BookDao;
import com.cjq.framework.ActionSupport;
import com.cjq.framework.ModelDriven;
import com.cjq.util.PageBean;public class BookAction extends ActionSupport implements ModelDriven<Book>{
private Book book=new Book();
private BookDao bookDao=new BookDao();public String list(HttpServletRequest req,HttpServletResponse resp ) {
 PageBean pageBean = new PageBean();
 pageBean.setRequest(req);
 try {
  List<Book> list = this.bookDao.list(book, pageBean);
  req.setAttribute("bookList", list);
  req.setAttribute("pageBean", pageBean);
  
 } catch (InstantiationException | IllegalAccessException | SQLException e) {
  e.printStackTrace();
 }
 return "list";
}
/**
 * 跳转新增修改页面（新增修改页面是同一个）
 * @param req
 * @param resp
 * @return
 */
public String preSave(HttpServletRequest req,HttpServletResponse resp) {
 if(book.getBid()!=0) {
  try {
   //数据回显的数据
   Book b = this.bookDao.list(book, null).get(0);
   req.setAttribute("book", b);
  } catch (InstantiationException | IllegalAccessException | SQLException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
 }
 return "edit";
}

public String add(HttpServletRequest req,HttpServletResponse resp) {
 try {
  this.bookDao.add(book);
 } catch (IllegalArgumentException | IllegalAccessException | SQLException e) {
  e.printStackTrace();
 }
 return "toList";
}

public String edit(HttpServletRequest req,HttpServletResponse resp) {
 try {
  this.bookDao.edit(book);
 } catch (IllegalArgumentException | IllegalAccessException | SQLException e) {
  // TODO Auto-generated catch block
  e.printStackTrace();
 }
 return "toList";
}

public String del(HttpServletRequest req,HttpServletResponse resp) {
 try {
  this.bookDao.del(book);
 } catch (IllegalArgumentException | IllegalAccessException | SQLException e) {
  e.printStackTrace();
 }
 return "toList";
}
@Override
public Book getModel() {
 return book;
}}

bookEdit.jsp

<%@ page language="java" contentType="text/html; charset=utf-8"
    pageEncoding="utf-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>书籍的编辑页面</title>
</head>
<body>
<form action="${pageContext.request.contextPath}/book.action?methodName=${book.bname==null ? 'add' : 'edit'}" method="post">
bid:<input type="text" value="${book.bid }" name="bid" ><br>
bname:<input type="text" value="${book.bname }" name="bname" ><br>
price:<input type="text" value="${book.price }" name="price" ><br>
<input type="submit" value="ok" >
</form>
</body>
</html>

bookList.jsp

<%@ page language="java" contentType="text/html; charset=utf-8"
    pageEncoding="utf-8"%>
    <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
     <%@ taglib uri="/onlyK" prefix="z" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>书籍主页</title>
</head>
<body>
 <h2>小说目录</h2>
 <br>
 <form action="${pageContext.request.contextPath}/book.action?methodName=list"
  method="post">
 <!-- 每页20行数据 --> 
   <!-- <input type="hidden" name='rows' value="20" > -->
   <!-- 不分页 -->
   <input type="hidden" name='pagination' value="false" >
  书名：<input type="text" name="bname"> 
  <!-- 书籍的类别：<input type="checkbox" name="bookType" value="1">玄幻
  <input type="checkbox" name="bookType" value="2">都市
  <input type="checkbox" name="bookType" value="3">言情 -->
  <input type="submit"
   value="确定">
 </form>
 <a href="${pageContext.request.contextPath}/book.action?methodName=preSave">新增</a>
 
 <table border="1" width="100%">
  <tr>
   <td>编号</td>
   <td>名称</td>
   <td>价格</td>
   <td>操作</td>
  </tr>
  <c:forEach items="${bookList }" var="b">
   <tr>
    <td>${b.bid }</td>
    <td>${b.bname }</td>
    <td>${b.price }</td>
    <td>
    <a href="${pageContext.request.contextPath}/book.action?methodName=preSave&&bid=${b.bid}">修改</a>
    <a href="${pageContext.request.contextPath}/book.action?methodName=del&&bid=${b.bid}">删除</a> 
    </td>
   </tr>
  </c:forEach>
 </table>
 
 <z:page pageBean="${pageBean }"></z:page>
 
 
<%--  <form id='pageBeanForm' action=' ${pageBean.url }' method='post'>
  <input type='hidden' name=''> <input type='hidden' name='page'>
 </form>
 
 <div style='text-align: right; font-size: 12px;'>
  每页N条，共N条，第N页，共N页&nbsp;&nbsp;<a href='javascript:gotoPage(?)'>首页</a>&nbsp;&nbsp;<a
   href='javascript:gotoPage(?)'>上一页</a>&nbsp;&nbsp;<a
   href='javascript:gotoPage(?)'>下一页</a>&nbsp;&nbsp;<a
   href='javascript:gotoPage(?)'>尾页</a>&nbsp;&nbsp;<input type='text'
   id='skipPage'
   style='text-align: center; font-size: 12px; width: 50px;'>&nbsp;&nbsp;<a
   href='javascript:skipPage()'>Go</a>
 </div> --%>
 
 <!-- <script type='text/javascript'>
  function gotoPage(page) {
   document.getElementById('pageBeanForm').page.value = page;
   document.getElementById('pageBeanForm').submit();
  }
  function skipPage() {
   var page = document.getElementById('skipPage').value;
   if(!page || isNaN(page) || parseInt(page)<1 || parseInt(page)>maxPage){
    alert('请输入1~N的数字');
    return;
   }
   gotoPage(page);
  }
 </script> --></body>
</html>

运行结果如下：
在这里插入图片描述
增加页面：