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复杂条件查询功能

时间：2023-01-06 17:01:09浏览次数：37  
标签：功能 rows 复杂 request 查询 pd import currentPage condition

复杂条件查询功能分析

 

 

 

总记录数统计的代码实现

UserDao接口：

    /**
     * 查询总记录数
     * @return
     */
    int findTotalCount(Map<String, String[]> condition);

    /**
     * 分页查询每页记录
     *
     * @param start
     * @param rows
     * @param condition
     * @return
     */
    List<User1> findByPage(int start, int rows, Map<String, String[]> condition);

UserDaoImpl实现类：

    @Override
    public int findTotalCount(Map<String, String[]> condition) {
        //1.定义sql
        String sql = "select count(*) from user1 where 1 = 1 ";
        StringBuilder sb = new StringBuilder(sql);

        //2.遍历map
        Set<String> keySet = condition.keySet();
        //定义参数集合
        List<Object> params = new ArrayList<>();
        for (String key : keySet) {

            if ("currentPage".equals(key) || "rows".equals(key)){
                continue;//结束当前循环继续下一个循环
            }


            //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 ? ");//拼接sql
                params.add("%"+value+"%");// ？条件的值
            }
        }
        System.out.println(sb.toString());
        System.out.println(params);
        return template.queryForObject(sb.toString(), Integer.class,params.toArray());
    }

UserService接口：

    /**
     * 批量删除用户
     * @param ids
     */
    void delSelectedUser(String[] ids);

    /**
     * 分页条件查询
     * @param currentPage
     * @param rows
     * @return
     */
    PageBean<User1> findUserByPage(String currentPage, String rows, Map<String,String[]> condition);

UserServiceImpl实体类：

    @Override
    public PageBean<User1> findUserByPage(String _currentPage, String _rows, Map<String,String[]> condition) {

        int currentPage = Integer.parseInt(_currentPage);
        int rows = Integer.parseInt(_rows);

        if (currentPage <= 0){
            currentPage = 1;
        }else if (currentPage >= 8){
            currentPage = 7;
        }

        //1.创建空的PageBean对象
        PageBean<User1> pd = new PageBean<User1>();

        //2.设置参数
        pd.setCurrentPage(currentPage);
        pd.setRows(rows);

        //3.调用dao查询totalCount总记录数
        int totalCount = dao.findTotalCount(condition);
        pd.setTotalCount(totalCount);

        //4.调用dao查询List集合
        //计算开始的记录索引
        int start = (currentPage -1) * rows;
        List<User1> list =  dao.findByPage(start,rows,condition);
        pd.setList(list);

        //5.计算总页码
        int totalPage = (totalCount % rows) == 0 ? totalCount/rows : (totalCount/rows) + 1;// 三元运算符

        pd.setTotalPage(totalPage);

        return pd;
    }

FindUserByPageServlet：

package com.example.web.servlet;

import com.example.domain.PageBean;
import com.example.domain.User1;
import com.example.service.UserService;
import com.example.service.impl.UserServiceImpl;

import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.annotation.*;
import java.io.IOException;
import java.util.Map;

@WebServlet(name = "FindUserByPageServlet", value = "/findUserByPageServlet")
public class FindUserByPageServlet 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 {
        request.setCharacterEncoding("utf-8");

        //1.获取参数
        String currentPage = request.getParameter("currentPage");// 获取当前页面参数
        String rows = request.getParameter("rows");// 获取每页条数

        if (currentPage == null || "".equals(currentPage) ){
            currentPage = "1";
        }
        if (rows == null || "".equals(rows)){
            rows = "5";

        }

        // 获取条件查询参数
        Map<String, String[]> condition = request.getParameterMap();


        //2.调用service查询
        UserService service = new UserServiceImpl();
        PageBean<User1> pd = service.findUserByPage(currentPage,rows,condition);

        System.out.println(pd);

        //3.将PageBean存入request存储
        request.setAttribute("pd", pd);
        //4.转发到list.jsp页面
        request.getRequestDispatcher("/list.jsp").forward(request, response);
    }
}

list.jsp：

        <form class="form-inline" action="${pageContext.request.contextPath}/findUserByPageServlet" method="post">
            <div class="form-group">
                <label for="exampleInputName2">姓名</label>
                <input type="text" name="name" class="form-control" id="exampleInputName2" placeholder="name">
            </div>
            <div class="form-group">
                <label for="exampleInputEmail2">籍贯</label>
                <input type="text" name="address" class="form-control" id="exampleInputEmail2" placeholder="address">
            </div>

            <div class="form-group">
                <label for="exampleInputEmail3">邮箱</label>
                <input type="email" name="email" class="form-control" id="exampleInputEmail3" placeholder="email">
            </div>

            <button type="submit" class="btn btn-default">查询</button>
        </form>

 

每页数据条件查询的代码实现

 UserDaoImpl实现类：

    @Override
    public List<User1> findByPage(int start, int rows, Map<String, String[]> condition) {
        //1.定义sql语句
        String sql = "select * from user1 where 1 = 1 ";

        StringBuilder sb = new StringBuilder(sql);
        //2.遍历map
        Set<String> keySet = condition.keySet();
        //定义参数集合
        List<Object> params = new ArrayList<>();
        for (String key : keySet) {

            if ("currentPage".equals(key) || "rows".equals(key)){
                continue;//结束当前循环继续下一个循环
            }


            //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 ? ");//拼接sql
                params.add("%"+value+"%");// ？条件的值
            }
        }

        //添加分页查询
        sb.append("limit ?,? ");
        //添加分页查询参数值
        params.add(start);
        params.add(rows);

        sql = sb.toString();
        System.out.println(sql);
        System.out.println(params);

        return template.query(sql, new BeanPropertyRowMapper<User1>(User1.class),params.toArray());
    }

FindUserByPageServlet：

package com.example.web.servlet;

import com.example.domain.PageBean;
import com.example.domain.User1;
import com.example.service.UserService;
import com.example.service.impl.UserServiceImpl;

import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.annotation.*;
import java.io.IOException;
import java.util.Map;

@WebServlet(name = "FindUserByPageServlet", value = "/findUserByPageServlet")
public class FindUserByPageServlet 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 {
        request.setCharacterEncoding("utf-8");

        //1.获取参数
        String currentPage = request.getParameter("currentPage");// 获取当前页面参数
        String rows = request.getParameter("rows");// 获取每页条数

        if (currentPage == null || "".equals(currentPage) ){
            currentPage = "1";
        }
        if (rows == null || "".equals(rows)){
            rows = "5";

        }

        // 获取条件查询参数
        Map<String, String[]> condition = request.getParameterMap();


        //2.调用service查询
        UserService service = new UserServiceImpl();
        PageBean<User1> pd = service.findUserByPage(currentPage,rows,condition);

        System.out.println(pd);

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

 

 

list.jsp：

<body>
<div class="container">
    <h3 style="text-align: center">用户信息列表</h3>

    <div style="float: left">

        <form class="form-inline" action="${pageContext.request.contextPath}/findUserByPageServlet" method="post">
            <div class="form-group">
                <label for="exampleInputName2">姓名</label>
                <input type="text" name="name" value="${condition.name[0]}" class="form-control" id="exampleInputName2" placeholder="name">
            </div>
            <div class="form-group">
                <label for="exampleInputEmail2">籍贯</label>
                <input type="text" name="address" value="${condition.address[0]}" class="form-control" id="exampleInputEmail2" placeholder="address">
            </div>

            <div class="form-group">
                <label for="exampleInputEmail3">邮箱</label>
                <input type="text" name="email" value="${condition.email[0]}"  class="form-control" id="exampleInputEmail3" placeholder="email">
            </div>

            <button type="submit" class="btn btn-default">查询</button>
        </form>

    </div>

    <div style="float: right; margin: 5px">

            <td colspan="8" align="center">

                <a class="btn btn-primary" href="${pageContext.request.contextPath}/add.jsp">添加联系人</a>

            </td>

            <td colspan="8" align="center">

                <a class="btn btn-primary" href="javascript:void(0);" id="delSelected">删除选中</a>

            </td>

    </div>

    <form id="from" action="${pageContext.request.contextPath}/delSelectedServlet" method="post">

    <table border="1" class="table table-bordered table-hover">
        <tr class="success">
            <th><input type="checkbox" id="firstCb"></th>
            <th>编号</th>
            <th>姓名</th>
            <th>性别</th>
            <th>年龄</th>
            <th>籍贯</th>
            <th>QQ</th>
            <th>邮箱</th>
            <th>操作</th>
        </tr>

        <c:forEach items="${pd.list}" var="user" varStatus="s">
            <tr>
                <td><input type="checkbox" name="uid" value="${user.id}"></td>
                <td>${s.count}</td>
                <td>${user.name}</td>
                <td>${user.gender}</td>
                <td>${user.age}</td>
                <td>${user.address}</td>
                <td>${user.qq}</td>
                <td>${user.email}</td>
                <td>
                    <a class="btn btn-default btn-sm" href="${pageContext.request.contextPath}/findUserServlet?id=${user.id}">修改</a>&nbsp;



                    <%--<a class="btn btn-default btn-sm" href="${pageContext.request.contextPath}/delUserServlet?id=${user.id}">删除</a>--%>
                    <a class="btn btn-default btn-sm" href="javascript:deleteUser(${user.id})">删除</a>

                </td>
            </tr>
        </c:forEach>
    </table>

    </form>

    <div>
        <nav aria-label="Page navigation">
            <ul class="pagination">
                <c:if test="${pd.currentPage == 1}">
                    <li class="disabled">

                </c:if>
                <c:if test="${pd.currentPage != 1}">
                    <li>
                </c:if>


                    <a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${pd.currentPage-1}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}" aria-label="Previous">
                        <span aria-hidden="true">&laquo;</span>
                    </a>
                </li>
                <c:forEach begin="1" end="${pd.totalPage}" var="i">

                    <!-- 分页选中 -->
                    <c:if test="${pd.currentPage == i}">
                        <li class="active"><a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${i}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}">${i}</a></li>
                    </c:if>


                    <c:if test="${pd.currentPage != i}">
                        <li><a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${i}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}">${i}</a></li>
                    </c:if>


                </c:forEach>

                <li>
                    <a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${pd.currentPage+1}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}" aria-label="Next">
                        <span aria-hidden="true">&raquo;</span>
                    </a>
                </li>
                <span style="font-size: 25px;margin-left: 5px">
                    共${pd.totalCount}条记录，共${pd.totalPage}页
                </span>
            </ul>
        </nav>
    </div>


</div>
</body>

 

标签：功能,rows,复杂,request,查询,pd,import,currentPage,condition
From： https://www.cnblogs.com/qihaokuan/p/17030981.html

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