自定义mvc增删改查

对t_mvc_book表的增删改查

导入jar包

BaseDao

package com.hmc.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;

/**
 * T代表你要对哪个实体类对应表进行查询
 *
 * @author Administrator
 *
 * @param <T>
 */
public class BaseDao<T> {

	/**
	 *
	 * @param sql 查询不同的实体类，那么对应的sql不同，所以需要传递
	 * @param clz  生产出不同的实体类对应的实例，然后装进list容器中返回
	 * @param pageBean  决定是否分页
	 * @return
	 * @throws Exception
	 */
	public List<T> executeQuery(String sql,Class clz,PageBean pageBean) throws Exception{

		Connection con=DBAccess.getConnection();
		PreparedStatement ps=null;
		ResultSet rs=null;
	   if(pageBean!=null&&pageBean.isPagination()) {
		   //需要分页(算符合条件的总记录数)
		   String countSql=getCountSql(sql);
		   ps=con.prepareStatement(countSql);
		   rs=ps.executeQuery();
		   if(rs.next()) {
			   pageBean.setTotal(rs.getLong(1)+"");
		   }
		   //查询出符合条件的结果集
		   String pageSql=getpageSql(sql,pageBean);
		   ps=con.prepareStatement(pageSql);
		   rs=ps.executeQuery();

	   }else {
		   ps=con.prepareStatement(sql);
		   rs=ps.executeQuery();
	   }

		List<T> list=new ArrayList<T>();
	    T t;
		while(rs.next()) {
		/**
		 * 1.实例化一个book对象（该对象是空的）
		 * 2.取book的所有的属性，然后给其赋值
		 *  2.1获取所有属性对象
		 *  2.2给属性对象赋值
		 * 3.赋完值的book对象装进list容器中
		 */
		t=(T)clz.newInstance();
			Field[] fields=clz.getDeclaredFields();
			for (Field field : fields) {
				field.setAccessible(true);
				field.set(t, rs.getObject(field.getName()));
			}
			list.add(t);
		}
		DBAccess.close(con, ps, rs);
		return list;
	}

	/**
	 * 利用原生sql拼接出符合条件的结果集的sql
	 * @param sql
	 * @param pageBean
	 * @return
	 */
	private String getpageSql(String sql, PageBean pageBean) {
		// TODO Auto-generated method stub
		return sql+" limit "+pageBean.getStartIndex()+","+pageBean.getRows();
	}

	/**
	 * 获取符合条件的总记录数的sql
	 * @param sql
	 * @return
	 */
	private String getCountSql(String sql) {

		return "SELECT COUNT(1)FROM ("+sql+")t";
	}

	/**
	 *
	 * @param sql 决定增删改的一种
	 * @param attrs 决定？位置 new String[]{"bid,"bname"}
	 * @param t 要操作的实体
	 * @return
	 * @throws Exception
	 * @throws NoSuchFieldException
	 */
	public int executeUpdate (String sql,String[] attrs,T t) throws NoSuchFieldException, Exception {
		Connection con=DBAccess.getConnection();
		PreparedStatement ps=con.prepareStatement(sql);
		for(int i=1;i<=attrs.length;i++) {
		Field f=t.getClass().getDeclaredField(attrs[i-1]);
		f.setAccessible(true);
		ps.setObject(i, f.get(t));
		}
		int num=ps.executeUpdate();
		DBAccess.close(con, ps, null);

		return num;
	}

}

　　Book(实体)

package com.hmc.entity;

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(int bid, String bname, float price) {
		super();
		this.bid = bid;
		this.bname = bname;
		this.price = price;
	}

	public Book() {
		super();
	}

}

　　BookDao

package com.hmc.dao;

import java.util.List;

import com.hmc.entity.Book;
import com.hmc.util.BaseDao;
import com.hmc.util.PageBean;
import com.hmc.util.StringUtils;

public class BookDao extends BaseDao<Book>{
	/**
	 * 查询所有
	 * @param book
	 * @param pageBean
	 * @return
	 * @throws Exception
	 */
  public List<Book> list(Book book,PageBean pageBean) throws Exception{
	  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); 

  }
  /**
   * 修改
   * @param book
   * @return
 * @throws Exception
 * @throws NoSuchFieldException
   */
  public int upde(Book book) throws NoSuchFieldException, Exception {
	  String sql="update t_mvc_book set bname=?,price=? where bid=?";
  return super.executeUpdate(sql, new String[] {"bname","price","bid"}, book);
  }

  /**
   * 新增
   * @param book
   * @return
 * @throws Exception
 * @throws NoSuchFieldException
   */
  public int add(Book book) throws NoSuchFieldException, Exception {
	  String sql="insert into t_mvc_book values(?,?,?)";
	  System.out.println(sql);
  return super.executeUpdate(sql, new String[] {"bid","bname","price"}, book);
  }

  /**
   * 删除
   * @param book
   * @return
 * @throws Exception
 * @throws NoSuchFieldException
   */
  public int del(Book book) throws NoSuchFieldException, Exception {
	  String sql="delete from t_mvc_book where bid=?";

  return super.executeUpdate(sql, new String[] {"bid"}, book);
  }
}

　　BookAction

package com.hmc.web;

import java.util.List;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.hmc.dao.BookDao;
import com.hmc.entity.Book;
import com.hmc.framework.ActionSupport;
import com.hmc.framework.ModelDrivern;
import com.hmc.util.PageBean;

public class BookAction extends ActionSupport implements ModelDrivern<Book>{
     private Book book=new Book();
     private BookDao bookdao=new BookDao();
     /**
      * 分页查询
      * @param request
      * @param response
      * @return
      * @throws Exception
      */

     public String list(HttpServletRequest request,HttpServletResponse response) throws Exception {
    	 PageBean pageBean=new PageBean();
    	 pageBean.setRequest(request);
    	 List<Book> list = this.bookdao.list(book, pageBean);
    	 request.setAttribute("booklist", list);
		 request.setAttribute("pagebean", pageBean);
    	 return "list";
     }

     /**
      *
      * 跳转到增加或修改页面
      * @param request
      * @param response
      * @return
      * @throws Exception
      */
     public String preSave(HttpServletRequest request,HttpServletResponse response) {
		//bid的类型是int类型，而int类型的默认值是0，如果jsp未传递bid的参数值那么bid=0;
    	 if(book.getBid()==0) {
			System.out.println("增加逻辑");

		  }
		else {
			//修改数据回显
			Book b;
			try {
				b = this.bookdao.list(book, null).get(0);
				request.setAttribute("book", b);
			} catch (Exception e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}

		}
    	 return "edit";

     }

     /**
      * 新增
      * @param request
      * @param response
      * @return
      * @throws Exception
      */
     public String add(HttpServletRequest request,HttpServletResponse response) throws Exception {
		//新增完了之后刷新页面
    	this.bookdao.add(book);
    	 return "tolist";

     }

      /**
       * 修改
       * @param request
       * @param response
       * @return
       * @throws Exception
       */
     public String upde(HttpServletRequest request,HttpServletResponse response) throws Exception {
 		//修改完了之后刷新页面
     	 this.bookdao.upde(book);
     	 return "tolist";

      }
     /**
      * 删除
      * @param request
      * @param response
      * @return
      * @throws Exception
      */
     public String del(HttpServletRequest request,HttpServletResponse response) throws Exception {
  		//删除之后刷新页面
      	this.bookdao.del(book);
      	return "tolist";
       }

	@Override
	public Book getModel() {
		// TODO Auto-generated method stub
		return book;
	}

}

　　mvc.xml

<?xml version="1.0" encoding="UTF-8"?>
<!-- config标签:可以包含0~N个action标签 -->
<config>
	<!-- action标签:可以饱含0~N个forward标签 path:以/开头的字符串,并且值必须唯一 非空 type:字符串,非空 -->

	<action path="/Cal" type="com.hmc.web.AddCalAction">
		<forward name="res" path="/res.jsp" redirect="false" />
	</action>
	<action path="/book" type="com.hmc.web.BookAction">
		<forward name="list" path="/book.jsp" redirect="false" />
		<forward name="edit" path="/booklist.jsp" redirect="false" />
		<forward name="tolist" path="/book.action?menthodName=list" />
	</action>
</config>

　　建立web层进行测试（book.jsp）

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
    <%@page isELIgnored="false" %>
    <%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
    <%@taglib prefix="z"  uri="/MyJSP"%>
<!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>Insert title here</title>
</head>
<body>
<h2>小说目录</h2>
	<br>

	<form action="${pageContext.request.contextPath}/book.action?menthodName=list"
		method="post">
		书名：<input type="text" name="bname"> <input type="submit"
			value="确定">

	</form>
	<a href="${pageContext.request.contextPath}/book.action?menthodName=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="${pageContext.request.contextPath}/book.action?menthodName=preSave&&bid=${b.bid}">修改</a>
				</td>
				<td><a href="${pageContext.request.contextPath}/book.action?menthodName=del&&bid=${b.bid}">删除</a>
				</td>
			</tr>
		</c:forEach>
	</table>
<z:page bean="${pagebean }"></z:page> 

</body>
</html>

　　

模糊查询

删除上面编号为23的

新增书籍

修改十里桃花为百里桃花