• JavaWeb：用户信息管理系统总结

    当当当当~~~~欢迎大家阅读，今天我们总结用户信息管理系统的流程

    该系统主要分为两部分，一部分是简单功能（增删改查）的基础实现；

    一部分是复杂功能删除选中，分页查询，复杂条件查询的实现；

    简单功能

    首先我们来看一下登录界面

    一：登录

    (一)：登录界面

    1:html登录界面

    2:html代码 

    1.   <body>
    2.   	<div class="container" style="width: 400px;">
    3.   		<h3 style="text-align: center;">管理员登录</h3>
    4.         <form action="login" method="post">
    5. 	      <div class="form-group">
    6. 	        <label for="user">用户名：</label>
    7. 	        <input type="text" name="user" class="form-control" id="user" placeholder="请输入用户名"/>
    8. 	      </div>
    9. 	      
    10. 	      <div class="form-group">
    11. 	        <label for="password">密码：</label>
    12. 	        <input type="password" name="password" class="form-control" id="password" placeholder="请输入密码"/>
    13. 	      </div>
    14. 	      
    15. 	      <div class="form-inline">
    16. 	        <label for="vcode">验证码：</label>
    17. 	        <input type="text" name="verifycode" class="form-control" id="verifycode" placeholder="请输入验证码" style="width: 120px;"/>
    18. 	        <a href="javascript:refreshCode()"><img src="vcode" title="看不清点击刷新" id="vcode"/></a>
    19. 	      </div>
    20. 	      <hr/>
    21. 	      <div class="form-group" style="text-align: center;">
    22. 	        <input class="btn btn btn-primary" type="submit" value="登录">
    23. 		  </div>
    24. 	  	</form>
    25. 		
    26. 		<!-- 出错显示的信息框 -->
    27. 	  	<div class="alert alert-warning alert-dismissible" role="alert">
    28. 		  <button type="button" class="close" data-dismiss="alert" >
    29. 		  	<span>&times;</span>
    30. 		  </button>
    31. 		   <strong>登录失败!</strong>
    32. 		</div>
    33.   	</div>
    34.   </body>

    3:改进后的jsp登录界面

    4:页面代码的改进

    在html基础上添加了servlet与后端交互，并且在登录时插入了验证码的校验

    1. <form action="${pageContext.request.contextPath}/loginServlet" method="post">
    2. <div class="form-inline">
    3.             <label for="vcode">验证码：</label>
    4.             <input type="text" name="verifycode" class="form-control" id="verifycode" placeholder="请输入验证码" style="width: 120px;"/>
    5.             <a href="javascript:refreshCode();">
    6.                 <img src="${pageContext.request.contextPath}/checkCodeServlet" title="看不清点击刷新" id="vcode"/>
    7.             </a>
    8. </div>

     (二)：后端代码实现

    1:LoginServlet

    1.  //1.设置编码
    2.         request.setCharacterEncoding("utf-8");
    3.  
    4.         //2.获取数据
    5.         //2.1获取用户填写验证码
    6.         String verifycode = request.getParameter("verifycode");
    7.  
    8.         //3.验证码校验
    9.         HttpSession session = request.getSession();
    10.         String checkcode_server = (String) session.getAttribute("CHECKCODE_SERVER");
    11.         session.removeAttribute("CHECKCODE_SERVER");//确保验证码一次性
    12.         if(!checkcode_server.equalsIgnoreCase(verifycode)){
    13.             //验证码不正确
    14.             //提示信息
    15.             request.setAttribute("login_msg","验证码错误！");
    16.             //跳转登录页面
    17.             request.getRequestDispatcher("/login.jsp").forward(request,response);
    18.  
    19.             return;
    20.         }
    21.  
    22.         Map<String, String[]> map = request.getParameterMap();
    23.         //4.封装User对象
    24.         User user = new User();
    25.         try {
    26.             BeanUtils.populate(user,map);
    27.         } catch (IllegalAccessException e) {
    28.             e.printStackTrace();
    29.         } catch (InvocationTargetException e) {
    30.             e.printStackTrace();
    31.         }
    32.  
    33.  
    34.         //5.调用Service查询
    35.         UserService service = new UserServiceImpl();
    36.         User loginUser = service.login(user);
    37.         //6.判断是否登录成功
    38.         if(loginUser != null){
    39.             //登录成功
    40.             //将用户存入session
    41.             session.setAttribute("user",loginUser);
    42.             //跳转页面
    43.             response.sendRedirect(request.getContextPath()+"/index.jsp");
    44.         }else{
    45.             //登录失败
    46.             //提示信息
    47.             request.setAttribute("login_msg","用户名或密码错误！");
    48.             //跳转登录页面
    49.             request.getRequestDispatcher("/login.jsp").forward(request,response);
    50.  
    51.         }

    2:UserServiceImpl(login)

    1.  @Override
    2.     public User login(User user) {
    3.  
    4.         return dao.findUserByUsernameAndPassword(user.getUsername(),user.getPassword());
    5.     }

    3:UserDaoImpl(findUserByUsernameAndPassword)

    1.  @Override
    2.     public User findUserByUsernameAndPassword(String username, String password) {
    3.         try {
    4.             String sql = "select * from user where username = ? and password = ?";
    5.             User user = template.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class), username, password);
    6.             return user;
    7.         } catch (Exception e) {
    8.             e.printStackTrace();
    9.             return null;
    10.         }
    11.  
    12.     }

    登录界面完成并且登录成功后，接下来我们开始进行用户信息的列表查询！

    二：查询

    (一)：查询界面

    1:点击查询所有用户信息进入用户信息列表界面

    1. <div align="center">
    2.     <a
    3.             href="${pageContext.request.contextPath}/findUserByPageServlet" style="text-decoration:none;font-size:33px">查询所有用户信息
    4.     </a>
    5. </div>

     

    2:查询界面的jsp代码

    1.         <table border="1" class="table table-bordered table-hover">
    2.         <tr class="success">
    3.             <th><input type="checkbox" id="firstCb"></th>
    4.             <th>编号</th>
    5.             <th>姓名</th>
    6.             <th>性别</th>
    7.             <th>年龄</th>
    8.             <th>籍贯</th>
    9.             <th>QQ</th>
    10.             <th>邮箱</th>
    11.             <th>操作</th>
    12.         </tr>
    13.  
    14.         <c:forEach items="${pb.list}" var="user" varStatus="s">
    15.             <tr>
    16.                 <td><input type="checkbox" name="uid" value="${user.id}"></td>
    17.                 <td>${s.count}</td>
    18.                 <td>${user.name}</td>
    19.                 <td>${user.gender}</td>
    20.                 <td>${user.age}</td>
    21.                 <td>${user.address}</td>
    22.                 <td>${user.qq}</td>
    23.                 <td>${user.email}</td>
    24.                 <td><a class="btn btn-default btn-sm" 
    25.  
    26.        </c:forEach>
    27.        </table>

     (二)：后端代码实现

    1:UserListServlet

    1. protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    2.         //1.调用UserService完成查询
    3.         UserService service = new UserServiceImpl();
    4.         List<User> users = service.findAll();
    5.         //2.将list存入request域
    6.         request.setAttribute("users",users);
    7.         //3.转发到list.jsp
    8.         request.getRequestDispatcher("/list.jsp").forward(request,response);
    9. }

    2:UserServiceImpl(findAll) 

    1.  @Override
    2.     public List<User> findAll() {
    3.         //调用Dao完成查询
    4.         return dao.findAll();
    5.     }

    3:UserDaoImpl(findAll) 

    1.  @Override
    2.     public List<User> findAll() {
    3.         //使用JDBC操作数据库...
    4.         //1.定义sql
    5.         String sql = "select * from user";
    6.         List<User> users = template.query(sql, new BeanPropertyRowMapper<User>(User.class));
    7.  
    8.         return users;
    9.     }

     三：添加用户信息

    (一)：添加界面 

    1:在list页面上补充一个添加联系人的按钮

    1. <div style="float: right;margin: 5px;">
    2.  
    3.         <a class="btn btn-primary" href="${pageContext.request.contextPath}/add.jsp">添加联系人</a>
    4.        
    5. </div>

    2:点击按钮进入添加联系人界面

    3:Add 界面的jsp代码

    1. <body>
    2. <div class="container">
    3.     <center><h3>添加联系人页面</h3></center>
    4.     <form action="${pageContext.request.contextPath}/addUserServlet" method="post">
    5.         <div class="form-group">
    6.             <label for="name">姓名：</label>
    7.             <input type="text" class="form-control" id="name" name="name" placeholder="请输入姓名">
    8.         </div>
    9.  
    10.         <div class="form-group">
    11.             <label>性别：</label>
    12.             <input type="radio" name="gender" value="男" checked="checked"/>男
    13.             <input type="radio" name="gender" value="女"/>女
    14.         </div>
    15.  
    16.         <div class="form-group">
    17.             <label for="age">年龄：</label>
    18.             <input type="text" class="form-control" id="age" name="age" placeholder="请输入年龄">
    19.         </div>
    20.  
    21.         <div class="form-group">
    22.             <label for="address">籍贯：</label>
    23.             <select name="address" class="form-control" id="address">
    24.                 <option value="陕西">陕西</option>
    25.                 <option value="北京">北京</option>
    26.                 <option value="上海">上海</option>
    27.             </select>
    28.         </div>
    29.  
    30.         <div class="form-group">
    31.             <label for="qq">QQ：</label>
    32.             <input type="text" class="form-control" id="qq" name="qq" placeholder="请输入QQ号码"/>
    33.         </div>
    34.  
    35.         <div class="form-group">
    36.             <label for="email">Email：</label>
    37.             <input type="text" class="form-control" id="email" name="email" placeholder="请输入邮箱地址"/>
    38.         </div>
    39.  
    40.         <div class="form-group" style="text-align: center">
    41.             <input class="btn btn-primary" type="submit" value="提交" />
    42.             <input class="btn btn-default" type="reset" value="重置" />
    43.             <input class="btn btn-default" type="button" value="返回" />
    44.         </div>
    45.     </form>
    46. </div>
    47. </body>

    (二)：后端代码实现

    1:添加功能的思路分析 

    2:AddUserServlet

    1. protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    2.         //1.设置编码
    3.         request.setCharacterEncoding("utf-8");
    4.         //2.获取参数
    5.         Map<String, String[]> map = request.getParameterMap();
    6.         //3.封装对象
    7.         User user = new User();
    8.         try {
    9.             BeanUtils.populate(user,map);
    10.         } catch (IllegalAccessException e) {
    11.             e.printStackTrace();
    12.         } catch (InvocationTargetException e) {
    13.             e.printStackTrace();
    14.         }
    15.  
    16.         //4.调用Service保存
    17.         UserService service = new UserServiceImpl();
    18.         service.addUser(user);
    19.  
    20.         //5.跳转到userListServlet
    21.             response.sendRedirect(request.getContextPath()+"/findUserByPageServlet");
    22.     }

    3:UserServiceImpl(addUser)

    1.     @Override
    2.     public void addUser(User user) {
    3.         dao.add(user);
    4.     }

    4:UserDaoImpl(add)

    1.  @Override
    2.     public void add(User user) {
    3.         //1.定义sql
    4.         String sql = "insert into user values(null,?,?,?,?,?,?,null,null)";
    5.         //2.执行sql
    6.         template.update(sql, user.getName(), user.getGender(), user.getAge(), user.getAddress(), user.getQq(), user.getEmail());
    7.     }

    四：删除单个用户信息

    (一)：添加删除按钮 

     <a class="btn btn-default btn-sm" href="javascript:deleteUser(${user.id});">删除</a></td>

    (二)：后端代码实现

    1:删除功能的思路分析

    2:DelUserServlet(先获取id,通过id,删除用户信息)

    1. protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    2.         //1.获取id
    3.         String id = request.getParameter("id");
    4.         //2.调用service删除
    5.         UserService service = new UserServiceImpl();
    6.         service.deleteUser(id);
    7.  
    8.         //3.跳转到查询所有Servlet
    9.         response.sendRedirect(request.getContextPath()+"/findUserByPageServlet");
    10. }
    11.

    3:UserServiceImpl(deleteUser)

    1.     @Override
    2.     public void deleteUser(String id) {
    3.         dao.delete(Integer.parseInt(id));
    4.     }

    4:UserDaoImpl(delete) 

    1.  @Override
    2.     public void delete(int id) {
    3.         //1.定义sql
    4.         String sql = "delete from user where id = ?";
    5.         //2.执行sql
    6.         template.update(sql, id);
    7. }

     五：修改用户信息

    (一)：修改用户信息界面

     1:html界面

    2:html代码

    1. <body>
    2.         <div class="container" style="width: 400px;">
    3.         <h3 style="text-align: center;">修改联系人</h3>
    4.         <form action="" method="post">
    5.           <div class="form-group">
    6.             <label for="name">姓名：</label>
    7.             <input type="text" class="form-control" id="name" name="name"  readonly="readonly" placeholder="请输入姓名" />
    8.           </div>
    9.  
    10.           <div class="form-group">
    11.             <label>性别：</label>
    12.               <input type="radio" name="sex" value="男"  />男
    13.                 <input type="radio" name="sex" value="女"  />女
    14.           </div>
    15.  
    16.           <div class="form-group">
    17.             <label for="age">年龄：</label>
    18.             <input type="text" class="form-control" id="age"  name="age" placeholder="请输入年龄" />
    19.           </div>
    20.  
    21.           <div class="form-group">
    22.             <label for="address">籍贯：</label>
    23.              <select name="address" id="address" class="form-control" >
    24.                 <option value="陕西">陕西</option>
    25.                 <option value="北京">北京</option>
    26.                 <option value="上海">上海</option>
    27.             </select>
    28.           </div>
    29.  
    30.           <div class="form-group">
    31.             <label for="qq">QQ：</label>
    32.             <input type="text" id="qq" class="form-control" name="qq" placeholder="请输入QQ号码"/>
    33.           </div>
    34.  
    35.           <div class="form-group">
    36.             <label for="email">Email：</label>
    37.             <input type="text" id="email" class="form-control" name="email" placeholder="请输入邮箱地址"/>
    38.           </div>
    39.  
    40.              <div class="form-group" style="text-align: center">
    41.                 <input class="btn btn-primary" type="submit" value="提交" />
    42.                 <input class="btn btn-default" type="reset" value="重置" />
    43.                 <input class="btn btn-default" type="button" value="返回"/>
    44.              </div>
    45.         </form>
    46.         </div>
    47.     </body>

    3:改进后的jsp修改界面

     4:页面改进后的代码

    添加可以自由选择性别和籍贯的判断

    1. <body>
    2.         <div class="container" style="width: 400px;">
    3.         <h3 style="text-align: center;">修改联系人</h3>
    4.         <form action="${pageContext.request.contextPath}/updateUserServlet" method="post">
    5.             <!--  隐藏域提交id-->
    6.             <input type="hidden" name="id" value="${user.id}">
    7.  
    8.           <div class="form-group">
    9.             <label for="name">姓名：</label>
    10.             <input type="text" class="form-control" id="name" name="name"  value="${user.name}" readonly="readonly" placeholder="请输入姓名" />
    11.           </div>
    12.  
    13.           <div class="form-group">
    14.             <label>性别：</label>
    15.               <c:if test="${user.gender == '男'}">
    16.                   <input type="radio" name="gender" value="男" checked />男
    17.                   <input type="radio" name="gender" value="女"  />女
    18.               </c:if>
    19.  
    20.               <c:if test="${user.gender == '女'}">
    21.                   <input type="radio" name="gender" value="男"  />男
    22.                   <input type="radio" name="gender" value="女" checked  />女
    23.               </c:if>
    24.  
    25.  
    26.           </div>
    27.  
    28.           <div class="form-group">
    29.             <label for="age">年龄：</label>
    30.             <input type="text" class="form-control" value="${user.age}" id="age"  name="age" placeholder="请输入年龄" />
    31.           </div>
    32.  
    33.           <div class="form-group">
    34.             <label for="address">籍贯：</label>
    35.              <select name="address" id="address" class="form-control" >
    36.                  <c:if test="${user.address == '陕西'}">
    37.                     <option value="陕西" selected>陕西</option>
    38.                     <option value="北京">北京</option>
    39.                     <option value="上海">上海</option>
    40.                  </c:if>
    41.  
    42.                  <c:if test="${user.address == '北京'}">
    43.                      <option value="陕西" >陕西</option>
    44.                      <option value="北京" selected>北京</option>
    45.                      <option value="上海">上海</option>
    46.                  </c:if>
    47.  
    48.                  <c:if test="${user.address == '上海'}">
    49.                      <option value="陕西" >陕西</option>
    50.                      <option value="北京">北京</option>
    51.                      <option value="上海" selected>上海</option>
    52.                  </c:if>
    53.             </select>
    54.           </div>
    55.         </form>
    56.         </div>
    57.     </body>

    (二)：后端代码实现

    1:修改功能的思路分析

    2:FindUserServlet

    1. protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    2.         //1.获取id
    3.         String id = request.getParameter("id");
    4.         //2.调用Service查询
    5.         UserService service = new UserServiceImpl();
    6.         User user = service.findUserById(id);
    7.  
    8.         //3.将user存入request
    9.         request.setAttribute("user",user);
    10.         //4.转发到update.jsp
    11.         request.getRequestDispatcher("/update.jsp").forward(request,response);
    12.     }

    3:UpdateUserServlet

    1.  protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    2.         //1.设置编码
    3.         request.setCharacterEncoding("utf-8");
    4.         //2.获取map
    5.         Map<String, String[]> map = request.getParameterMap();
    6.         //3.封装对象
    7.         User user = new User();
    8.         try {
    9.             BeanUtils.populate(user,map);
    10.         } catch (IllegalAccessException e) {
    11.             e.printStackTrace();
    12.         } catch (InvocationTargetException e) {
    13.             e.printStackTrace();
    14.         }
    15.  
    16.         //4.调用Service修改
    17.         UserService service = new UserServiceImpl();
    18.         service.updateUser(user);
    19.  
    20.         //5.跳转到查询所有Servlet
    21.         response.sendRedirect(request.getContextPath()+"/findUserByPageServlet");
    22.     }

    4:UserServiceImpl(updateUser)

    1.  @Override
    2.     public void updateUser(User user) {
    3.         dao.update(user);
    4.     }

    5:UserDaoImpl(update)

    1. @Override
    2.     public void update(User user) {
    3.         String sql = "update user set name = ?,gender = ? ,age = ? , address = ? , qq = ?, email = ? where id = ?";
    4.         template.update(sql, user.getName(), user.getGender(), user.getAge(), user.getAddress(), user.getQq(), user.getEmail(), user.getId());
    5.     }

    复杂功能

    一：删除选中

     (一)：删除选中界面

    1:在list页面添加删除选中的按钮，并且给删除选中添加单击事件

    1.     <div style="float: right;margin: 5px;">
    2.         <a class="btn btn-primary" href="javascript:void(0);" id="delSelected">删除选中 
    3.         </a>
    4.  
    5.     </div> 
    6.             window.onload = function(){
    7.             //给删除选中按钮添加单击事件
    8.             document.getElementById("delSelected").onclick = function(){
    9.                 if(confirm("您确定要删除选中条目吗？")){
    10.                    var flag = false;
    11.                     //判断是否有选中条目
    12.                     var cbs = document.getElementsByName("uid");
    13.                     for (var i = 0; i < cbs.length; i++) {
    14.                         if(cbs[i].checked){
    15.                             //有一个条目选中了
    16.                             flag = true;
    17.                             break;
    18.                         }
    19.                     }
    20.                     if(flag){//有条目被选中
    21.                         //表单提交
    22.                         document.getElementById("form").submit();
    23.                     }
    24.                 }
    25.             }
    26.           }

    2:删除选中时可以添加全部选中

    1.  //1.获取第一个cb
    2.             document.getElementById("firstCb").onclick = function(){
    3.                 //2.获取下边列表中所有的cb
    4.                 var cbs = document.getElementsByName("uid");
    5.                 //3.遍历
    6.                 for (var i = 0; i < cbs.length; i++) {
    7.                     //4.设置这些cbs[i]的checked状态 = firstCb.checked
    8.                     cbs[i].checked = this.checked;
    9.                 }
    10.             }

    (二)：后端代码实现

    1:删除选中的思路分析

    2:DelSelectedServlet

    1. public class DelSelectedServlet extends HttpServlet {
    2.     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    3.         //1.获取所有id
    4.         String[] ids = request.getParameterValues("uid");
    5.         //2.调用service删除
    6.         UserService service = new UserServiceImpl();
    7.         service.delSelectedUser(ids);
    8.  
    9.         //3.跳转查询所有Servlet
    10.         response.sendRedirect(request.getContextPath()+"/findUserByPageServlet");
    11.     }

    3:UserService(delSelectedUser)

    1.   //删除选中用户
    2.     @Override
    3.     public void delSelectedUser(String[] ids) {
    4.         if(ids != null && ids.length > 0){
    5.             //1.遍历数组
    6.             for (String id : ids) {
    7.                 //2.调用dao删除
    8.                 dao.delete(Integer.parseInt(id));
    9.             }
    10.         }
    11.     }

    二：分页查询

    (一)：分页查询页面 

    1:在list.jsp中添加组件分页栏

    1. <div>
    2.         <nav aria-label="Page navigation">
    3.             <ul class="pagination">
    4.                 <c:if test="${pb.currentPage == 1}">
    5.                     <li class="disabled">
    6.                 </c:if>
    7.                 <c:if test="${pb.currentPage != 1}">
    8.                 <li>
    9.                 </c:if>
    10.                     <a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${pb.currentPage - 1}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}" aria-label="Previous">
    11.                         <span aria-hidden="true">&laquo;</span>
    12.                     </a>
    13.                 </li>
    14.                 <c:forEach begin="1" end="${pb.totalPage}" var="i" >
    15.                     <c:if test="${pb.currentPage == i}">
    16.                         <li class="active"><a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${i}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}">${i}</a></li>
    17.                     </c:if>
    18.                     <c:if test="${pb.currentPage != i}">
    19.                         <li><a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${i}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}">${i}</a></li>
    20.                     </c:if>
    21.                 </c:forEach>
    22.                 <li>
    23.                     <a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${pb.currentPage + 1}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}" aria-label="Next">
    24.                         <span aria-hidden="true">&raquo;</span>
    25.                     </a>
    26.                 </li>
    27.                 <span style="font-size: 25px;margin-left: 5px;">
    28.                     共${pb.totalCount}条记录，共${pb.totalPage}页
    29.                 </span>
    30.  
    31.             </ul>
    32.         </nav>
    33. </div>

    (二)：后端代码实现

    1:分页查询实体类的思路分析

    1：添加一个分页查询相关的类

    1. public class PageBean<T> {
    2.     private int totalCount; // 总记录数
    3.     private int totalPage ; // 总页码
    4.     private List<T> list ; // 每页的数据
    5.     private int currentPage ; //当前页码
    6.     private int rows;//每页显示的记录数

    2:分页查询的逻辑思路分析

    3:FindUserByPageServlet

    1. protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    2.         request.setCharacterEncoding("utf-8");
    3.         //1.获取参数
    4.         String currentPage = request.getParameter("currentPage");//当前页码
    5.         String rows = request.getParameter("rows");//每页显示条数
    6.  
    7.         if(currentPage == null || "".equals(currentPage)){
    8.  
    9.             currentPage = "1";
    10.         }
    11.         if(rows == null || "".equals(rows)){
    12.             rows = "5";
    13.         }
    14.         //获取条件查询参数
    15.         Map<String, String[]> condition = request.getParameterMap();
    16.         //2.调用service查询
    17.         UserService service = new UserServiceImpl();
    18.         PageBean<User> pb = service.findUserByPage(currentPage,rows,condition);
    19.         System.out.println(pb);
    20.         //3.将PageBean存入request
    21.         request.setAttribute("pb",pb);
    22.         request.setAttribute("condition",condition);//将查询条件存入request
    23.         //4.转发到list.jsp
    24.         request.getRequestDispatcher("/list.jsp").forward(request,response);
    25.     }

    4:UserService(findUserByPage)

    1. //分页条件查询
    2.     @Override
    3.     public PageBean<User> findUserByPage(String _currentPage, String _rows, Map<String, String[]> condition) {
    4.  
    5.         int currentPage = Integer.parseInt(_currentPage);
    6.         int rows = Integer.parseInt(_rows);
    7.  
    8.         //第1页的上一页永远返回1
    9.         if(currentPage <=0) {
    10.             currentPage = 1;
    11.         }
    12.  
    13.         //1.创建空的PageBean对象
    14.         PageBean<User> pb = new PageBean<User>();
    15.         //2.设置参数
    16.         pb.setCurrentPage(currentPage);
    17.         pb.setRows(rows);
    18.  
    19.         //3.调用dao查询总记录数
    20.         int totalCount = dao.findTotalCount(condition);
    21.         pb.setTotalCount(totalCount);
    22.         //4.调用dao查询List集合
    23.         //计算开始的记录索引
    24.         int start = (currentPage - 1) * rows;
    25.         List<User> list = dao.findByPage(start,rows,condition);
    26.         pb.setList(list);
    27.  
    28.         //5.计算总页码
    29.         int totalPage = (totalCount % rows)  == 0 ? totalCount/rows : (totalCount/rows) + 1;
    30.         pb.setTotalPage(totalPage);
    31.  
    32.  
    33.         return pb;
    34.     }

    5:UserDaoImpl(findTotalCount)

    1. //查询总记录数
    2.     @Override
    3.     public int findTotalCount() {
    4.         //1.定义模板初始化sql
    5.         String sql = "select count(*) from user";
    6.       
    7.         return template.queryForObject(sql,Integer.class);
    8.     }

    6:UserDaoImpl(findByPage) 

    1.  //分页条件查询
    2.     @Override
    3.     public List<User> findByPage(int start, int rows) {
    4.         String sql = "select * from user limit?,? ;
    5.         return template.query(sql,new BeanPropertyRowMapper<User>,start,rows);
    6.     }

    三：复杂条件查询

    (一)：复杂条件查询界面

    1:复杂条件查询的界面展示 

     2:复杂条件查询的jsp代码

    1. <div style="float: left;">
    2.  
    3.         <form class="form-inline" action="${pageContext.request.contextPath}/findUserByPageServlet" method="post">
    4.             <div class="form-group">
    5.                 <label for="exampleInputName2">姓名</label>
    6.                 <input type="text" name="name" value="${condition.name[0]}" class="form-control" id="exampleInputName2" >
    7.             </div>
    8.             <div class="form-group">
    9.                 <label for="exampleInputName3">籍贯</label>
    10.                 <input type="text" name="address" value="${condition.address[0]}" class="form-control" id="exampleInputName3" >
    11.             </div>
    12.  
    13.             <div class="form-group">
    14.                 <label for="exampleInputEmail2">邮箱</label>
    15.                 <input type="text" name="email" value="${condition.email[0]}" class="form-control" id="exampleInputEmail2"  >
    16.             </div>
    17.             <button type="submit" class="btn btn-default">查询</button>
    18.         </form>
    19.  
    20. </div>

    (二)：后端代码实现

    1:复杂条件查询的思路分析

    2:在分页查询的FindUserByPageServlet基础上查询复杂条件的参数集合并传参

    1. //获取条件查询参数
    2.         Map<String, String[]> condition = request.getParameterMap();
    3. //2.调用service查询
    4.         UserService service = new UserServiceImpl();
    5.         PageBean<User> pb = service.findUserByPage(currentPage,rows,condition);
    6.         System.out.println(pb);

    3:在分页查询的UserService(findUserByPage) 的基础上传参

    1. //3.调用dao查询总记录数
    2.         int totalCount = dao.findTotalCount(condition);
    3.         pb.setTotalCount(totalCount);
    4.         //4.调用dao查询List集合
    5.         //计算开始的记录索引
    6.         int start = (currentPage - 1) * rows;
    7.         List<User> list = dao.findByPage(start,rows,condition);
    8.         pb.setList(list);

    4:在分页查询的UserDaoImpl(findTotalCount)基础上判断复杂条件查询是否有值并且获取值

    1. //查询总记录数
    2.     @Override
    3.     public int findTotalCount(Map<String, String[]> condition) {
    4.         //1.定义模板初始化sql
    5.         String sql = "select count(*) from user where 1 = 1 ";
    6.         StringBuilder sb = new StringBuilder(sql);
    7.         //2.遍历map
    8.         Set<String> keySet = condition.keySet();
    9.         //定义参数的集合
    10.         List<Object> params = new ArrayList<Object>();
    11.         for (String key : keySet) {
    12.  
    13.             //排除分页条件参数
    14.             if("currentPage".equals(key) || "rows".equals(key)){
    15.                 continue;
    16.             }
    17.  
    18.             //获取value
    19.             String value = condition.get(key)[0];
    20.             //判断value是否有值
    21.             if(value != null && !"".equals(value)){
    22.                 //有值
    23.                 sb.append(" and "+key+" like ? ");
    24.                 params.add("%"+value+"%");//？条件的值
    25.             }
    26.         }
    27.         System.out.println(sb.toString());
    28.         System.out.println(params);
    29.  
    30.         return template.queryForObject(sb.toString(),Integer.class,params.toArray());
    31.     }

    5:在分页查询的UserDaoImpl(findByPage) 基础上遍历复杂条件查询的集合并为查询到的值做分页处理

    1.  //分页条件查询
    2.     @Override
    3.     public List<User> findByPage(int start, int rows, Map<String, String[]> condition) {
    4.         String sql = "select * from user  where 1 = 1 ";
    5.  
    6.         StringBuilder sb = new StringBuilder(sql);
    7.         //2.遍历map
    8.         Set<String> keySet = condition.keySet();
    9.         //定义参数的集合
    10.         List<Object> params = new ArrayList<Object>();
    11.         for (String key : keySet) {
    12.  
    13.             //排除分页条件参数
    14.             if("currentPage".equals(key) || "rows".equals(key)){
    15.                 continue;
    16.             }
    17.  
    18.             //获取value
    19.             String value = condition.get(key)[0];
    20.             //判断value是否有值
    21.             if(value != null && !"".equals(value)){
    22.                 //有值
    23.                 sb.append(" and "+key+" like ? ");
    24.                 params.add("%"+value+"%");//？条件的值//模糊查询
    25.             }
    26.         }
    27.  
    28.         //添加分页查询
    29.         sb.append(" limit ?,? ");
    30.         //添加分页查询参数值
    31.         params.add(start);
    32.         params.add(rows);
    33.         sql = sb.toString();
    34.         System.out.println(sql);
    35.         System.out.println(params);
    36.  
    37.         return template.query(sql,new BeanPropertyRowMapper<User>(User.class),params.toArray());
    38.     }

    以上就是用户信息管理系统的内容啦，希望我的文章对你有所帮助，如果有错误的地方还望大家批评指正，谢谢大家阅读!  

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  • 原文地址：https://blog.csdn.net/Z2658172512/article/details/124960165