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JavaWeb用户信息查看的登录、增删改查案例

来源：保捱科技网

案例源码：

一、需求

实现页面跳转和用户信息的增删改查操作

二、设计

1、技术选型

Servlet+JSP+MySQL+JDBCTempleat+Duird+BeanUtilS+tomcat+BootStrap

2、数据库设计

SQL语句

create database heima; -- 创建数据库
			use heima; 			   -- 使用数据库
			create table day17_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)
			);

三、开发步骤

1. 环境搭建
		1. 创建数据库环境
		2. 创建项目，导入需要的jar包

2. 编码


3. 测试
4. 部署运维

本笔记（不包含测试和运维）

四、详细过程

1、创建web项目，部署tomcat，导入jar包

2、编写首页index.jsp

3、编写servlet、servie、daomain、dao

导入druid.properties，导入JDBCUtils类。源码都在源码链接中

五、案例升级实现

1、实现内容

2、list.jsp新增设计

按钮位置
输入框
分页条
复选框

3、实现登录功能

login.jsp设计

用到了checkCodeServlet，在我的其他博客写了，链接？？
login.jsp点击切换验证码实现，如下图

LoginServlet编写

@WebServlet(value = "/loginServlet")
public class LoginServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doPost(request, response);
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //1.设置编码
        request.setCharacterEncoding("utf-8");
        //2.获取数据
        //2.1获取用户填写验证码
        String verifycode = request.getParameter("verifycode");
        //3.验证码校验
        HttpSession session = request.getSession();
        String checkcode_server = (String) session.getAttribute("CHECKCODE_SERVER");
        session.removeAttribute("CHECKCODE_SERVER");

        //忽略大小写判断相等
        if (!checkcode_server.equalsIgnoreCase(verifycode)){
            //盐城吗不正确
            //提示信息
            request.setAttribute("login_msg", "验证码错误！");
            //跳转登录页面
            request.getRequestDispatcher("/login.jsp").forward(request,response);

            return;
        }

        Map<String, String[]> map = request.getParameterMap();
        //4.封装User对象
        User user = new User();
        try {
            BeanUtils.populate(user, map);
        }catch (IllegalAccessException e){
            e.printStackTrace();
        }catch (InvocationTargetException e){
            e.printStackTrace();
        }

        //5.调用Srvice查询
        UserService service = new UserServiceImpl();
        User loginUser = service.login(user);

        //6.判断是否登录成功
        if(loginUser != null){
            //登录成功
            //将用户存入session
            session.setAttribute("user",loginUser);
            //跳转页面
            response.sendRedirect(request.getContextPath()+"/index.jsp");
        }else{
            //登录失败
            //提示信息
            request.setAttribute("login_msg","用户名或密码错误！");
            //跳转登录页面
            request.getRequestDispatcher("/login.jsp").forward(request,response);

        }
    }
}

UserDaoImpl语句

/**
     * 登录账号
     * @param username
     * @param password
     * @return
     */
    @Override
    public User findUserByUsernameAndPassword(String username, String password) {

        try {
            String sql = "select * from day17_user where username = ? and password= ?";
            User user = template.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class), username, password);
            return user;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

4、实现添加功能

add.jsp编写

源码在顶部链接
注意事项：提交路径

AddUserServlet编写

@WebServlet(value = "/addUserServlet")
public class AddUserServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doPost(request, response);
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //1.设置编码
        request.setCharacterEncoding("utf-8");
        //2.获取参数
        Map<String, String[]> map = request.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保存
        UserService service = new UserServiceImpl();
        service.addUser(user);

        //5.跳转到userListServlet
        response.sendRedirect(request.getContextPath()+"/userListServlet");
    }
}

userDaoImpl语句

/**
     * 添加user
     * @param user
     */
    @Override
    public void add(User user) {
        String sql = "insert into day17_user values(null,?,?,?,?,?,?,null,null)";
//        template.update(sql, user.getName(), user.getGender(), user.getAge(), user.getAddress(), user.getQq(), user.getEmail());
        template.update(sql, user.getName(), user.getGender(), user.getAge(), user.getAddress(), user.getQq(), user.getEmail());
    }

5、实现删除功能

list.jsp修改

DelUserServlet

@WebServlet("/delUserServlet")
public class DelUserServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doPost(request, response);
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //1.获取id
        String id =request.getParameter("id");
        //2.调用service删除
        UserService service = new UserServiceImpl();
        service.deleteUser(id);
        //3.跳转到查询所有Servlet
        response.sendRedirect(request.getContextPath()+"/userListServlet");

    }
}

userDaoImpl增加语句

/**
     * 根据id删除
     * @param id
     */
    @Override
    public void delete(int id) {
        String sql = "delete from day17_user where id = ?";
        template.update(sql,id);
    }

6、修改功能实现

注意：隐藏域提交id。下面内容会提到

list.jsp增加修改发送路径

<a class="btn btn-default btn-sm" href="${pageContext.request.contextPath}/findUserServlet?id=${user.id}">修改</a>

FindUserServlet编写

@WebServlet(value = "/findUserServlet")
public class FindUserServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doPost(request, response);
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //1.获取id
        String id = request.getParameter("id");
        //2.调用Service查询
        UserService service = new UserServiceImpl();
        User user = service.findUserBuId(id);
        //3.将user存入request
        request.setAttribute("user",user);
        //4.转发到update.jsp
        request.getRequestDispatcher("/update.jsp").forward(request,response);
    }
}

update.jsp编写

id提交隐藏域如下

以下注意地点举例，具体请查看开篇源码链接。

UpdateUserServlet编写

@WebServlet(value = "/updateUserServlet")
public class UpdateUserServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doPost(request, response);
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //1.设置编码
        request.setCharacterEncoding("utf-8");
        //2.获取map
        Map<String, String[]> map = request.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
        response.sendRedirect(request.getContextPath()+"/userListServlet");
    }
}

UserServiceImpl实现方法

UserDaoImpl实现方法

7、删除选中功能

list.jsp编写

DelSelectServlet编写

@WebServlet(value = "/delSelectServlet")
public class DelSelectServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doPost(request, response);
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //1.获取所有id
        String[] ids = request.getParameterValues("uid");
        //
        UserService service = new UserServiceImpl();
        service.delSelectUser(ids);
        //
        response.sendRedirect(request.getContextPath()+"/userListServlet");
    }
}

UserServiceImpl编写

 @Override
    public void delSelectUser(String[] ids) {
        //判断有东西才删除，否则会空指针异常
        if (ids != null && ids.length>0){
            //1.遍历数组
            for (String id : ids){
                //2.2.调用dao删除
                dao.delete(Integer.parseInt(id));
            }
        }

    }

UserDaoImpl编写

还是用之前写的，不过就是上一步的service将选中的id列表挨个遍历传进来，挨个删除，还是用以前的方法

/**
     * 根据id删除
     * @param id
     */
    @Override
    public void delete(int id) {
        String sql = "delete from day17_user where id = ?";
        template.update(sql,id);
    }

8、实现全选，全不选和提示是否删除框

list.jsp编写实现

有选中条目才提交删除

同样Service中也要判断一下提交的里边有无内容，不判断的话有时候会空指针异常