1.将框架打成jar包，然后导入新工程，并且把框架的依赖jar包导入进去
二.实现增删改查
1.编写实体类、dao类、
1.1 实体类
package com.zhanghao.entity; public class Book { private int bid; private String bname; private float 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; } @Override public String toString() { return "Book [bid=" + bid + ", bname=" + bname + ", price=" + price + "]"; } public Book(int bid, String bname, float price) { super(); this.bid = bid; this.bname = bname; this.price = price; } public Book() { super(); } }
dao：通用的增删改查
package com.zhanghao.util; import java.lang.reflect.Field; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.util.ArrayList; import java.util.List; import com.zhanghao.util.DBAccess; import com.zhanghao.util.PageBean; import com.zhanghao.util.StringUtils; /** * 所有Dao层的父类 * BookDao * UserDao * OrderDao * ... * @author Administrator * * @param <T> */ public class BaseDao<T> { /** * 通用的增删改方法 * @param book * @throws Exception */ public void executeUpdate(String sql, T t, String[] attrs) throws Exception { // String[] attrs = new String[] {"bid", "bname", "price"}; Connection con = DBAccess.getConnection(); PreparedStatement pst = con.prepareStatement(sql); // pst.setObject(1, book.getBid()); // pst.setObject(2, book.getBname()); // pst.setObject(3, book.getPrice()); /* * 思路： * 1.从传进来的t中读取属性值 * 2.往预定义对象中设置了值 * * t->book * f->bid */ for (int i = 0; i < attrs.length; i++) { Field f = t.getClass().getDeclaredField(attrs[i]); f.setAccessible(true); pst.setObject(i+1, f.get(t)); } pst.executeUpdate(); } /** * 通用分页查询 * @param sql * @param clz * @return * @throws Exception */ public List<T> executeQuery(String sql,Class<T> clz,PageBean pageBean) throws Exception{ List<T> list = new ArrayList<T>(); Connection con = DBAccess.getConnection();; PreparedStatement pst = null; ResultSet rs = null; /* * 是否需要分页？ * 无需分页（项目中的下拉框，查询条件教员下拉框，无须分页） * 必须分页（项目中列表类需求、订单列表、商品列表、学生列表...） */ if(pageBean != null && pageBean.isPagination()) { // 必须分页（列表需求） String countSQL = getCountSQL(sql); pst = con.prepareStatement(countSQL); rs = pst.executeQuery(); if(rs.next()) { pageBean.setTotal(String.valueOf(rs.getObject(1))); } // 挪动到下面，是因为最后才处理返回的结果集 // -- sql=SELECT * FROM t_mvc_book WHERE bname like '%圣墟%' // -- pageSql=sql limit (page-1)*rows,rows 对应某一页的数据 // -- countSql=select count(1) from (sql) t 符合条件的总记录数 String pageSQL = getPageSQL(sql,pageBean);//符合条件的某一页数据 pst = con.prepareStatement(pageSQL); rs = pst.executeQuery(); }else { // 不分页（select需求） pst = con.prepareStatement(sql);//符合条件的所有数据 rs = pst.executeQuery(); } while (rs.next()) { T t = clz.newInstance(); Field[] fields = clz.getDeclaredFields(); for (Field f : fields) { f.setAccessible(true); f.set(t, rs.getObject(f.getName())); } list.add(t); } return list; } /** * 将原生SQL转换成符合条件的总记录数countSQL * @param sql * @return */ private String getCountSQL(String sql) { // -- countSql=select count(1) from (sql) t 符合条件的总记录数 return "select count(1) from ("+sql+") t"; } /** * 将原生SQL转换成pageSQL * @param sql * @param pageBean * @return */ private String getPageSQL(String sql,PageBean pageBean) { // (this.page - 1) * this.rows // pageSql=sql limit (page-1)*rows,rows return sql + " limit "+ pageBean.getStartIndex() +","+pageBean.getRows(); } }
Doa分页查询和通用增删改：
package com.zhanghao.dao; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.SQLException; import java.util.List; import com.zhanghao.entity.Book; import com.zhanghao.util.BaseDao; import com.zhanghao.util.DBAccess; import com.zhanghao.util.PageBean; import com.zhanghao.util.StringUtils; public class BookDao extends BaseDao<Book>{ /* * public void add(Book book) throws Exception { String sql = "insert into t_mvc_book values(?,?,?)"; Connection con = DBAccess.getConnection(); PreparedStatement pst = con.prepareStatement(sql); pst.setObject(1, book.getBid()); pst.setObject(2, book.getBname()); pst.setObject(3, book.getPrice()); pst.executeUpdate(); } 增删改查的通用套路 1.建立链接 2.预定义对象PreparedStatement 3.设置占位符的？的值 4.pst.executeUpdate(); 1. */ public void add(Book book) throws Exception { String sql = "insert into t_mvc_book values(?,?,?)"; super.executeUpdate(sql, book, new String[] {"bid","bname","price"}); } public void edit(Book book) throws Exception { String sql = "update t_mvc_book set bname = ?, price = ? where bid = ?"; super.executeUpdate(sql, book, new String[] {"bname","price","bid"}); } public void delete(Book book) throws Exception { String sql = "delete from t_mvc_book where bid = ?"; super.executeUpdate(sql, book, new String[] {"bid"}); } public List<Book> list(Book book,PageBean pageBean) throws Exception { String sql = "select * from t_mvc_book where 1=1 "; String bname = book.getBname(); if(StringUtils.isNotBlank(bname)) { sql += " and bname like '%"+bname+"%'"; } return super.executeQuery(sql, Book.class, pageBean); } public static void main(String[] args) throws Exception { Book b = new Book(); b.setBid(2323); b.setBname("测试www"); b.setPrice(231f); BookDao bookDao = new BookDao(); // bookDao.delete(b); // bookDao.add(b); bookDao.edit(b); } public List<Book> list(String string, PageBean pageBean) { // TODO Auto-generated method stub return null; } }
后台代码：
package com.zhanghao.web; import java.util.List; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import com.zhanghao.dao.BookDao; import com.zhanghao.entity.Book; import com.zhanghao.util.PageBean; import com.zking.framework.ActionSupport; import com.zking.framework.ModelDriven; public class BookAction extends ActionSupport implements ModelDriven<Book>{ private Book book = new Book(); private BookDao bookDao = new BookDao(); public Book getModel() { return book; } /* * 增删改最终都要跳回查询界面 * 分析增删改查一共有多少结果集的配置 * 查询：BookList.jsp 返回值：list * 增删改确定：book.action?methodName=list 返回值：toList * 增加修改跳转对应界面：bookEdit.jsp 返回值：toEdit */ public String add(HttpServletRequest req, HttpServletResponse resp) { try { bookDao.add(book); } catch (Exception e) { e.printStackTrace(); } return "toList"; } public String list(HttpServletRequest req, HttpServletResponse resp) { try { PageBean pageBean = new PageBean(); pageBean.setRequest(req); List<Book> list = bookDao.list("book", pageBean); req.setAttribute("books", list); req.setAttribute("pageBean", pageBean); } catch (Exception e) { e.printStackTrace(); } return "list"; } public String delete(HttpServletRequest req, HttpServletResponse resp) { try { bookDao.delete(book); } catch (Exception e) { e.printStackTrace(); } return "toList"; } public String edit(HttpServletRequest req, HttpServletResponse resp) { try { bookDao.edit(book); } catch (Exception e) { e.printStackTrace(); } return "toList"; } /** * 跳转到新增修改页面 * @param req * @param resp * @return */ public String toEdit(HttpServletRequest req, HttpServletResponse resp) { try { /* * 如果是跳转修改页面，那么需要做bid条件的精准查询 */ if(book.getBid() != 0) { List<Book> list = bookDao.list(book, null); req.setAttribute("b", list.get(0)); } } catch (Exception e) { e.printStackTrace(); } return "toEdit"; } }
前台页面：
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@ taglib uri="http://jsp.veryedu.cn" prefix="z"%> <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%> <!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"> <link href="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/4.5.0/css/bootstrap.css" rel="stylesheet"> <script src="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/4.5.0/js/bootstrap.js"></script> <title>书籍新增/修改</title> </head> <body> <form class="form-inline" action="${pageContext.request.contextPath }/book.action?methodName=${empty b ? 'add' : 'edit'}" method="post"> 书籍ID：<input type="text" name="bid" value="${b.bid }"><br> 书籍名称：<input type="text" name="bname" value="${b.bname }"><br> 书籍价格：<input type="text" name="price" value="${b.price }"><br> <input type="submit"> </form> </body> </html>
