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
* @param condition
*/
int FindTotalCount(Map<String, String[]> condition);
/**
* 分页查询每页记录
* @param start
* @param rows
* @param condition
* @return
*/
List<User> fingByPage(int start, int rows, Map<String, String[]> condition);
UserDaoImpl实现类：
@Override
public int FindTotalCount(Map<String, String[]> condition) {
//定义模板初始化sql
String sql = "select count(*) from user where 1 = 1 ";
StringBuilder sb = new StringBuilder(sql);
//遍历map
Set<String> keySet = condition.keySet();
//定义参数的集合
List<Object> 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.println(sb.toString());
System.out.println(params);
return template.queryForObject(sb.toString(),Integer.class,params.toArray());
}
UserService接口：
/**
* 分页条件查询
* @param currentPage
* @param rows
* @param condition
* @return
*/
PageBean<User> findUserByPage(String currentPage, String rows, Map<String, String[]> condition);
UserServiceImpl实现类：
@Override
public PageBean<User> findUserByPage(String _currentPage, String _rows, Map<String, String[]> condition) {
int currentPage = Integer.parseInt(_currentPage);
int rows = Integer.parseInt(_rows);
//判读最小页码
if (currentPage < 1){
currentPage = 1;
}
//1、创建空的PageBean对象
PageBean<User> pb = new PageBean<>();
//3、调用dao查询总记录数
int totalCount = dao.FindTotalCount(condition);
pb.setTotalCount(totalCount);
//5、计算总页码
int totalPage = (totalCount%rows)==0 ? totalCount/rows : (totalCount/rows)+1;
//判断最大页码
if (currentPage >totalPage){
currentPage = totalPage;
}
//2、设置参数
pb.setCurrentPage(currentPage);
pb.setRows(rows);
//4、调用dao查询list集合
//计算开始的记录索引
int start = (currentPage-1)*rows;
List<User> list = dao.fingByPage(start,rows,condition);
pb.setList(list);
pb.setTotalPage(totalPage);
return pb;
}
FindUserByPageServlet类：
@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<String, String[]> condition = request.getParameterMap();
//2、调用servic查询
UserService service = new UserServiceImpl();
PageBean<User> pb = service.findUserByPage(currentPage,rows,condition);
//3、将PageBean存入request
request.setAttribute("pb",pb);
//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);
}
}
list.jsp：
<form class="form-inline" action="${pageContext.request.contextPath}/findUserByPageServlet" method="post">
<div class="form-group">
<label for="exampleInputName2">姓名</label>
<input type="text" class="form-control" id="exampleInputName2" name="name">
</div>
<div class="form-group">
<label for="exampleInputName3">籍贯</label>
<input type="text" class="form-control" id="exampleInputName3" name="address">
</div>
<div class="form-group">
<label for="exampleInputEmail2">邮箱</label>
<input type="email" class="form-control" id="exampleInputEmail2" name="email">
</div>
<button type="submit" class="btn btn-default">查询</button>
</form>
每页数据条件查询的代码实现
UserDaoImpl实现类：
@Override
public List<User> fingByPage(int start, int rows, Map<String, String[]> condition) {
String sql = "select * from user where 1 = 1";
StringBuilder sb = new StringBuilder(sql);
//遍历map
Set<String> keySet = condition.keySet();
//定义参数的集合
List<Object> params = new ArrayList<>();
for (String key : keySet) {
//排除分页条件参数
if("currentPage".equals(key) || "rows".equals(key)){
continue;
}
//获取value
String value = condition.get(key)[0];
//判断value是否有值
if(value != null && !"".equals(value)){
//有值
sb.append(" and "+key+" like ? ");
params.add("%"+value+"%");//? 条件的值
}
}
//添加分页查询
sb.append(" limit ?,? ");
//添加分页查询参数值
params.add(start);
params.add(rows);
return template.query(sb.toString(),new BeanPropertyRowMapper<User>(User.class),params.toArray());
}
list.jsp：
<body>
<div class="container">
<h3 style="text-align: center">用户信息列表</h3>
<div style="float: left;">
<form class="form-inline" action="${pageContext.request.contextPath}/findUserByPageServlet" method="post">
<div class="form-group">
<label for="exampleInputName2">姓名</label>
<input type="text" class="form-control" id="exampleInputName2" name="name" value="${condition.name[0]}">
</div>
<div class="form-group">
<label for="exampleInputName3">籍贯</label>
<input type="text" class="form-control" id="exampleInputName3" name="address" value="${condition.address[0]}">
</div>
<div class="form-group">
<label for="exampleInputEmail2">邮箱</label>
<input type="text" class="form-control" id="exampleInputEmail2" name="email" value="${condition.email[0]}">
</div>
<button type="submit" class="btn btn-default">查询</button>
</form>
</div>
<div style="float:right;margin: 5px;">
<a class="btn btn-primary" href="${pageContext.request.contextPath}/add.jsp">添加联系人</a>
<a class="btn btn-primary" href="javascript:void(0);" id="delSelected">删除选中</a>
</div>
<form id="form" action="${pageContext.request.contextPath}/delSelectedServlet" method="post">
<table border="1" class="table table-bordered table-hover">
<tr class="success">
<th><input type="checkbox" id="firstCb"></th>
<th>编号</th>
<th>姓名</th>
<th>性别</th>
<th>年龄</th>
<th>籍贯</th>
<th>QQ</th>
<th>邮箱</th>
<th>操作</th>
</tr>
<c:forEach items="${pb.list}" var="user" varStatus="s">
<tr>
<th><input type="checkbox" name="uid" value="${user.id}"></th>
<td>${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>
<a class="btn btn-default btn-sm" href="javascript:deleteUser(${user.id});">删除</a>
</td>
</tr>
</c:forEach>
</table>
</form>
<div>
<nav aria-label="Page navigation">
<ul class="pagination">
<c:if test="${pb.currentPage == 1}">
<li class="disabled">
</c:if>
<c:if test="${pb.currentPage != 1}">
<li>
</c:if>
<a href="${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">
<span aria-hidden="true">«</span>
</a>
</li>
<c:forEach begin="1" end="${pb.totalPage}" var="i">
<c:if test="${pb.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="${pb.currentPage != i}">
<li><a href="${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=${pb.currentPage+1}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}" aria-label="Next">
<span aria-hidden="true">»</span>
</a>
</li>
<span style="font-size: 25px;margin-left: 5px;">
共${pb.totalCount}条记录，共${pb.totalPage}页
</span>
</ul>
</nav>
</div>
</div>
</body>
标签：功能,rows,String,复杂,value,查询,pb,currentPage,condition From： https://www.cnblogs.com/xjw12345/p/16597646.html