1、servlet层
package com.ycz.controller;import com.alibaba.fastjson.JSON;import com.ycz.dao.PeopleDao;import com.ycz.domain.People;import javax.servlet.ServletException;import javax.servlet.ServletRequest;import javax.servlet.ServletResponse;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import java.io.IOException;import java.io.PrintWriter;import java.text.SimpleDateFormat;import java.util.Calendar;import java.util.Date;import java.util.List;/** * @Description * @ClassName MyServlet * @Author yanchengzhi * @date 2021.06.06 20:16 */public class MyServlet extends HttpServlet { PeopleDao peopleDao = new PeopleDao(); /* * @description: servlet的核心方法，每个servlet请求都会经过此方法处理 * @param: [req, res] * @return: void * @author: yanchengzhi * @date: 2021/6/14 10:52 */ @Override public void service(ServletRequest req, ServletResponse res) throws ServletException, IOException { HttpServletRequest request = (HttpServletRequest)req; HttpServletResponse response = (HttpServletResponse)res; String command = request.getParameter("COMMAND"); if("ADD".equals(command)) { addPeople(request,response); return; } if("UPDATE".equals(command)){ updatePeople(request,response); return; } if("DEL".equals(command)) { deletePeople(request,response); return; } if("FIND".equals(command)) { findById(request,response); return; } if("FINDALL".equals(command)) { findAll(request,response); return; } } /* * @description: 添加 * @param: [request, response] * @return: void * @author: yanchengzhi * @date: 2021/6/14 10:51 */ private void addPeople(HttpServletRequest request,HttpServletResponse response) throws IOException { People people = new People(); people.setName("云过梦无痕"); people.setBirth(new Date()); people.setTag(0); response.setContentType("text/html;charset=utf-8"); //response.setContentType("text/plain; charset=UTF-8"); PrintWriter writer = response.getWriter(); int res = peopleDao.addPeople(people); if(res > 0){ writer.write("<h2>添加成功！</h2>"); } else { writer.write("<h2>添加失败！</h2>"); } writer.flush(); writer.close(); } /* * @description: 修改 * @param: [request, response] * @return: void * @author: yanchengzhi * @date: 2021/6/14 10:54 */ private void updatePeople(HttpServletRequest request,HttpServletResponse response) throws IOException { // 获取修改记录的id Integer id = Integer.parseInt(request.getParameter("id")); People p = new People(); p.setName("yanchengzhi"); Calendar calendar = Calendar.getInstance(); calendar.set(1995,9,18); Date date = calendar.getTime(); p.setBirth(date); int res = peopleDao.updatePeople(p,id); response.setContentType("text/html;charset=utf-8"); PrintWriter writer = response.getWriter(); if(res > 0){ writer.write("<h2>修改成功！</h2>"); } else { writer.write("<h2>修改成功！</h2>"); } writer.flush(); writer.close(); } /* * @description: 删除记录 * @param: [request, response] * @return: void * @author: yanchengzhi * @date: 2021/6/14 12:15 */ private void deletePeople(HttpServletRequest request,HttpServletResponse response) throws IOException{ Integer id = Integer.parseInt(request.getParameter("id")); int res = peopleDao.delPeople(id); response.setContentType("text/html;charset=utf-8"); PrintWriter writer = response.getWriter(); if(res > 0) { writer.write("<h2>删除成功！</h2>"); } else { writer.write("<h2>删除失败！</h2>"); } writer.flush(); writer.close(); } /* * @description: 按照id查询 * @param: [request, response] * @return: void * @author: yanchengzhi * @date: 2021/6/14 14:20 */ private void findById(HttpServletRequest request,HttpServletResponse response) { Integer id = Integer.parseInt(request.getParameter("id")); People p = peopleDao.findById(id); if(p != null) { System.out.println("查找的记录信息如下："); System.out.println("-------------------"); System.out.println("Id号：" + p.getId()); System.out.println("姓名：" + p.getName()); SimpleDateFormat sdf = new SimpleDateFormat("yyyy年MM月dd日"); System.out.println("生日：" + sdf.format(p.getBirth())); System.out.println("Tag标记：" + p.getTag()); } else { System.out.println("查询的记录不存在！"); } } private void findAll(HttpServletRequest request,HttpServletResponse response) throws IOException{ List<People> list = peopleDao.findAll(); response.setContentType("text/plain;charset=utf-8"); PrintWriter writer = response.getWriter(); if(list != null && list.size() > 0){ // 转为json串 String jsonStr = JSON.toJSONString(list); writer.write(jsonStr); } else { writer.write("查无数据！"); } }}
关注重点是service方法里的这些代码：
然后jsp中的代码如下：
可以看到一个共同点，就是所有的a链接后面都带有一个COMMAND参数，只是绑定的值不一样，就是根据这个绑定的值，来进入到不同的业务方法中。
2、dao层代码
package com.ycz.dao;import com.ycz.conf.DataSourceManager;import com.ycz.domain.People;import java.sql.Connection;import java.sql.Date;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.util.ArrayList;import java.util.List;/** * @Description 数据访问层 * @ClassName PeopleDao * @Author yanchengzhi * @date 2021.06.08 08:50 */public class PeopleDao { /* * @description: 添加 * @param: [people] * @return: int * @author: yanchengzhi * @date: 2021/6/14 11:03 */ public int addPeople(People people){ int res = 0; String sql = "insert into people (name,birth,tag) values (?,UNIX_TIMESTAMP(?),?)"; Connection connection = DataSourceManager.getConnection(); PreparedStatement ps = null; try { ps = connection.prepareStatement(sql); ps.setString(1,people.getName()); ps.setDate(2,new Date(people.getBirth().getTime())); ps.setInt(3,people.getTag()); res = ps.executeUpdate(); } catch (Exception e){ e.printStackTrace(); } finally { DataSourceManager.closeConnection(connection); DataSourceManager.closeStatement(ps); } return res; } /* * @description: 修改 * @param: [p, id] * @return: int * @author: yanchengzhi * @date: 2021/6/14 11:03 */ public int updatePeople(People p, Integer id) { int res = 0; String sql = "update people set name = ?,birth = UNIX_TIMESTAMP(?) where id = ?"; Connection connection = DataSourceManager.getConnection(); PreparedStatement ps = null; try { ps = connection.prepareStatement(sql); ps.setString(1,p.getName()); ps.setDate(2,new Date(p.getBirth().getTime())); ps.setInt(3,id); res = ps.executeUpdate(); } catch (Exception e){ e.printStackTrace(); } finally { DataSourceManager.closeConnection(connection); DataSourceManager.closeStatement(ps); } return res; } /* * @description: 删除 * @param: [id] * @return: int * @author: yanchengzhi * @date: 2021/6/14 12:20 */ public int delPeople(Integer id) { int res = 0; String sql = "delete from people where id = ?"; Connection connection = DataSourceManager.getConnection(); PreparedStatement ps = null; try { ps = connection.prepareStatement(sql); ps.setInt(1,id); res = ps.executeUpdate(); } catch (Exception e) { e.printStackTrace(); } finally { DataSourceManager.closeConnection(connection); DataSourceManager.closeStatement(ps); } return res; } /* * @description: 按照id查询 * @param: [id] * @return: com.ycz.domain.People * @author: yanchengzhi * @date: 2021/6/14 14:20 */ public People findById(Integer id) { String sql = "select id,name,FROM_UNIXTIME(birth) birthday,tag from people where id = ?"; Connection connection = DataSourceManager.getConnection(); PreparedStatement ps = null; ResultSet resultSet = null; try { ps = connection.prepareStatement(sql); ps.setInt(1,id); resultSet = ps.executeQuery(); while(resultSet.next()){ People p = new People(); p.setId(resultSet.getInt("id")); p.setName(resultSet.getString("name")); p.setBirth(resultSet.getDate("birthday")); p.setTag(resultSet.getInt("tag")); return p; } } catch (Exception e) { e.printStackTrace(); } finally { DataSourceManager.closeConnection(connection); DataSourceManager.closeStatement(ps); DataSourceManager.closeResultSet(resultSet); } return null; } /* * @description: 查询所有记录 * @param: [] * @return: java.util.List<com.ycz.domain.People> * @author: yanchengzhi * @date: 2021/6/14 14:43 */ public List<People> findAll() { List<People> peoples = new ArrayList<>(); String sql = "select id,name,FROM_UNIXTIME(birth) birthday,tag from people"; Connection connection = DataSourceManager.getConnection(); PreparedStatement ps = null; ResultSet resultSet = null; try { ps = connection.prepareStatement(sql); resultSet = ps.executeQuery(); while(resultSet.next()){ People p = new People(); p.setId(resultSet.getInt("id")); p.setName(resultSet.getString("name")); p.setBirth(resultSet.getDate("birthday")); p.setTag(resultSet.getInt("tag")); peoples.add(p); } } catch (Exception e) { e.printStackTrace(); } finally { DataSourceManager.closeConnection(connection); DataSourceManager.closeStatement(ps); DataSourceManager.closeResultSet(resultSet); } return peoples; }}
3、web.xml
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