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Java--小项目（登录、增删改查、分页、搜索）

2020-12-24 21:31

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Java--小项目（登录、增删改查、分页、搜索）

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概念

技术选型

Servlet、JSP、MySQL、JDBCTempleat、Duird、BeanUtilS、tomcat

功能介绍

登录功能，列表展示，数据添加，数据编辑，数据删除，批量删除，分页展示，关键字搜索

创建JavaWeb项目

技术图片

导入依赖

技术图片

添加页面文件

技术图片

数据库

create database little; -- 创建数据库
use little; 			   -- 使用数据库
create table user(   -- 创建表
	id int primary key auto_increment,
	name varchar(20) not null,
	gender varchar(5),
	age int,
	address varchar(32),
	qq	varchar(20),
	email varchar(50,
	username varchar(32),
  password varchar(32),
);

列表展示

思路

首先我们需要一组列表的数据，那么我们就需要一个相对应servlet，通过我们的三层架构，使用service同一做接口，然后调用dao层使用JBDC操作数据库，这样我们可以获得一个map集合的数据，然后就是渲染数据到jsp页面了，通过JSTL和EL把数据循环渲染到表里面，达到列表的展示

list.jsp










用户信息管理系统




    
用户信息列表

    



编号
            姓名
            性别
            年龄
            籍贯
            QQ
            邮箱
            操作
        



${s.count}
                ${user.name}
                ${user.gender}
                ${user.age}
                ${user.address}
                ${user.qq}
                ${user.email}
                修改 删除
            

添加联系人
servlet

代码文件很多，就不一一展示了

技术图片

UserListServlet
package cn.guizimo.little.web.servlet;

import cn.guizimo.little.domain.User;
import cn.guizimo.little.service.UserService;
import cn.guizimo.little.service.impl.UserServiceImpl;

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.util.List;

@WebServlet("/userListServlet")
public class UserListServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //调用UserService完成查询
        UserService userService = new UserServiceImpl();
        List users = userService.findAll();
        //存入request域
        req.setAttribute("users",users);
        //转发到list.jsp
        req.getRequestDispatcher("/list.jsp").forward(req,resp);
    }

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req, resp);
    }
}
测试

技术图片

登录

思路

登录功能首先就是对表单提交的数据进行比对，验证码可以在生成的时候就把它存入到session中，然后在servlet中进行比对，其他的字段在通过调用dao层的JDBC操作数据库进行比对，最后把登录成功的用户信息存入session中

login.jsp








管理员登录



    
管理员登录
LoginServlet
package cn.guizimo.little.web.servlet;

import cn.guizimo.little.domain.User;
import cn.guizimo.little.service.UserService;
import cn.guizimo.little.service.impl.UserServiceImpl;
import org.apache.commons.beanutils.BeanUtils;


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 javax.servlet.http.HttpSession;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.util.Map;

@WebServlet("/loginServlet")
public class LoginServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //设置编码
        req.setCharacterEncoding("utf-8");
        //传递过来的验证码
        String verifycode = req.getParameter("verifycode");
        HttpSession session = req.getSession();
        //session里面的验证码
        String checkcode_server = (String) session.getAttribute("CHECKCODE_SERVER");
        session.removeAttribute("CHECKCODE_SERVER");
        //比对验证码
        if (!checkcode_server.equalsIgnoreCase(verifycode)) {
            req.setAttribute("login_msg", "验证码错误");
            req.getRequestDispatcher("/login.jsp").forward(req, resp);
            return;
        }

        Map parameterMap = req.getParameterMap();
        User user = new User();
        try {
            BeanUtils.populate(user, parameterMap);
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }

        UserService userService = new UserServiceImpl();
        User loginUser = userService.login(user);
        if(loginUser != null){
            session.setAttribute("user",loginUser);
            resp.sendRedirect(req.getContextPath()+"/index.jsp");
        }else {
            req.setAttribute("login_msg", "登录失败");
            req.getRequestDispatcher("/login.jsp").forward(req, resp);
        }


    }

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req, resp);
    }
}
CheckCodeServlet
package cn.guizimo.little.web.servlet;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * 验证码
 */
@WebServlet("/checkCodeServlet")
public class CheckCodeServlet extends HttpServlet {
	public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
		
		//服务器通知浏览器不要缓存
		response.setHeader("pragma","no-cache");
		response.setHeader("cache-control","no-cache");
		response.setHeader("expires","0");
		
		//在内存中创建一个长80，宽30的图片，默认黑色背景
		//参数一：长
		//参数二：宽
		//参数三：颜色
		int width = 80;
		int height = 30;
		BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
		
		//获取画笔
		Graphics g = image.getGraphics();
		//设置画笔颜色为灰色
		g.setColor(Color.GRAY);
		//填充图片
		g.fillRect(0,0, width,height);
		
		//产生4个随机验证码，12Ey
		String checkCode = getCheckCode();
		//将验证码放入HttpSession中
		request.getSession().setAttribute("CHECKCODE_SERVER",checkCode);
		
		//设置画笔颜色为黄色
		g.setColor(Color.YELLOW);
		//设置字体的小大
		g.setFont(new Font("黑体",Font.BOLD,24));
		//向图片上写入验证码
		g.drawString(checkCode,15,25);
		
		//将内存中的图片输出到浏览器
		//参数一：图片对象
		//参数二：图片的格式，如PNG,JPG,GIF
		//参数三：图片输出到哪里去
		ImageIO.write(image,"PNG",response.getOutputStream());
	}
	/**
	 * 产生4位随机字符串 
	 */
	private String getCheckCode() {
		String base = "0123456789ABCDEFGabcdefg";
		int size = base.length();
		Random r = new Random();
		StringBuffer sb = new StringBuffer();
		for(int i=1;i
测试

技术图片

添加人员

思路

添加操作就是把jsp提交的表单的数据向数据库里面存储，过程为jsp->servlet->service->dao

add.jsp










添加用户



    
添加联系人页面

    

        

            
            



        

            
            男
            女
AddUserServlet
package cn.guizimo.little.web.servlet;

import cn.guizimo.little.domain.User;
import cn.guizimo.little.service.UserService;
import cn.guizimo.little.service.impl.UserServiceImpl;
import org.apache.commons.beanutils.BeanUtils;

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.lang.reflect.InvocationTargetException;
import java.util.Map;

@WebServlet("/addUserServlet")
public class AddUserServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("utf-8");
        Map parameterMap = req.getParameterMap();
        User user = new User();
        try {
            BeanUtils.populate(user,parameterMap);
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }
        UserService userService = new UserServiceImpl();
        userService.addUser(user);
        resp.sendRedirect(req.getContextPath()+"/userListServlet");
    }

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req, resp);
    }
}
测试

技术图片

修改

思路

首先我们需要在打开jsp页面的时候就查询到这样的一条记录，通过这一条记录的id作为表单的隐藏域，在servlet里面将数据进行保存即可

update.jsp










修改用户



    
修改联系人

    

        
        

            
            



        

            
            男
                女
            男
                女
            



        

            
            



        

            
            



        

            
            



        

            
            



        

            
            返回
FindUserServlet
package cn.guizimo.little.web.servlet;

import cn.guizimo.little.domain.User;
import cn.guizimo.little.service.UserService;
import cn.guizimo.little.service.impl.UserServiceImpl;

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;

@WebServlet("/findUserServlet")
public class FindUserServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //1.获取id
        String id = req.getParameter("id");
        //2.调用Service查询
        UserService service = new UserServiceImpl();
        User user = service.findUserById(id);

        //3.将user存入request
        req.setAttribute("user",user);
        //4.转发到update.jsp
        req.getRequestDispatcher("/update.jsp").forward(req,resp);
    }

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req, resp);
    }
}
UpdateUserServlet
package cn.guizimo.little.web.servlet;

import cn.guizimo.little.domain.User;
import cn.guizimo.little.service.UserService;
import cn.guizimo.little.service.impl.UserServiceImpl;
import org.apache.commons.beanutils.BeanUtils;

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.lang.reflect.InvocationTargetException;
import java.util.Map;

@WebServlet("/updateUserServlet")
public class UpdateUserServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //1.设置编码
        req.setCharacterEncoding("utf-8");
        //2.获取map
        Map map = req.getParameterMap();
        //3.封装对象
        User user = new User();
        try {
            BeanUtils.populate(user,map);
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }

        //4.调用Service修改
        UserService service = new UserServiceImpl();
        service.updateUser(user);

        //5.跳转到查询所有Servlet
        resp.sendRedirect(req.getContextPath()+"/userListServlet");
    }

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req, resp);
    }
}
测试

技术图片

删除

思路

通过获取到对应的id即可到servlet中处理，操作数据库删除，在进行删除的时候可出现提示框

DelUserServlet
package cn.guizimo.little.web.servlet;

import cn.guizimo.little.service.UserService;
import cn.guizimo.little.service.impl.UserServiceImpl;

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;

@WebServlet("/delUserServlet")
public class DelUserServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //1.获取id
        String id = req.getParameter("id");
        //2.调用service删除
        UserService service = new UserServiceImpl();
        service.deleteUser(id);

        //3.跳转到查询所有Servlet
        resp.sendRedirect(req.getContextPath()+"/userListServlet");
    }

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req, resp);
    }
}
测试

技术图片

删除选择的多个

思路

和删除差不多，最主要是获取id的集合

DelSelectedServlet
package cn.guizimo.little.web.servlet;

import cn.guizimo.little.service.UserService;
import cn.guizimo.little.service.impl.UserServiceImpl;

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;

@WebServlet("/delSelectedServlet")
public class DelSelectedServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //1.获取所有id
        String[] ids = req.getParameterValues("uid");
        //2.调用service删除
        UserService service = new UserServiceImpl();
        service.delSelectedUser(ids);

        //3.跳转查询所有Servlet
        resp.sendRedirect(req.getContextPath()+"/userListServlet");
    }

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req, resp);
    }
}
测试

技术图片

分页

思路

在jsp中获取查询的总条数，每页显示的条数，当前的页码，将之传递给服务器，操作数据库进行查询

list.jsp












用户信息管理系统




    
用户信息列表

    


        

            

                
                


            

                
                



            

                
                


            
        

    


    

        添加联系人
        删除选中
    

    

        




                编号
                姓名
                性别
                年龄
                籍贯
                QQ
                邮箱
                操作
            




                    ${s.count}
                    ${user.name}
                    ${user.gender}
                    ${user.age}
                    ${user.address}
                    ${user.qq}
                    ${user.email}
                    
                        修改 
                        删除
FindUserByPageServlet
package cn.guizimo.little.web.servlet;


import cn.guizimo.little.domain.PageBean;
import cn.guizimo.little.domain.User;
import cn.guizimo.little.service.UserService;
import cn.guizimo.little.service.impl.UserServiceImpl;

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.util.Map;

@WebServlet("/findUserByPageServlet")
public class FindUserByPageServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        request.setCharacterEncoding("utf-8");

        //1.获取参数
        String currentPage = request.getParameter("currentPage");//当前页码
        String rows = request.getParameter("rows");//每页显示条数

        if(currentPage == null || "".equals(currentPage)){
            currentPage = "1";
        }

        if(rows == null || "".equals(rows)){
            rows = "5";
        }
        
        //获取条件查询参数
        Map condition = request.getParameterMap();

        //2.调用service查询
        UserService service = new UserServiceImpl();
        PageBean pb = service.findUserByPage(currentPage,rows,condition);

        System.out.println(pb);

        //3.将PageBean存入request
        request.setAttribute("pb",pb);
        request.setAttribute("condition",condition);//将查询条件存入request
        //4.转发到list.jsp
        request.getRequestDispatcher("/list.jsp").forward(request,response);
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doPost(request, response);
    }
}
测试

技术图片

条件查询

思路

主要是在sql语句的编写

jsp
dao层方法
@Override
    public int findTotalCount(Map condition) {
        //1.定义模板初始化sql
        String sql = "select count(*) from user where 1 = 1 ";
        StringBuilder sb = new StringBuilder(sql);
        //2.遍历map
        Set keySet = condition.keySet();
        //定义参数的集合
        List params = new ArrayList();
        for (String key : keySet) {
            //排除分页条件参数
            if("currentPage".equals(key) || "rows".equals(key)){
                continue;
            }
            //获取value
            String value = condition.get(key)[0];
            //判断value是否有值
            if(value != null && !"".equals(value)){
                //有值
                sb.append(" and "+key+" like ? ");
                params.add("%"+value+"%");//？条件的值
            }
        }
        System.out.print

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文章标题：Java--小项目（登录、增删改查、分页、搜索）
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