servlet实现jsp列表的搜索框_使用jsp+servlet实现搜索-优快云博客

本文链接：https://blog.youkuaiyun.com/qq761789003/article/details/107554485

这里我们对一个列表的信息进行搜索，根据姓名部门
在这里插入图片描述用到的工具和jsp的位置

jsp页面

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

<html>
<head>
    <title>Title</title>
    <style type="text/css">
        table{
            background: dimgrey;
            margin: auto;
            width: 40%;
        }
        th,td{
            background: white;
        }
    </style>
</head>
<body>

 <table>
     <tr>
        <td colspan="6">
            <form action="${pageContext.request.contextPath}/FindServlet" method="post" style="margin: auto">
            姓名：<input type="text" name="name">
            部门：<select id="dept" name="deptno">
                    <option value="0">请选择</option>
                </select>
            <input type="submit" value="搜索">
        </form>
        </td>
     </tr>
     <tr>
         <th>id</th>
         <th>姓名</th>
         <th>工作</th>
         <th>部门编号</th>
         <th>部门名称</th>
         <th>操作</th>
     </tr>
     <c:forEach items="${emps}" var="e">
         <tr align="center">
             <td>${e.empno}</td>
             <td>${e.ename}</td>
             <td>${e.job}</td>
             <td>${e.dept.deptno}</td>
             <td>${e.dept.dname}</td>
             <td><a href="javascript:del(${e.empno})">删除</a>&nbsp;&nbsp;
                 <a href="${pageContext.request.contextPath}/Servlet?method=edit&id=${e.empno}">修改</a> </td>
         </tr>
     </c:forEach>
 </table>
</body>
<script type="text/javascript" src="${pageContext.request.contextPath}/js/jquery-3.1.0.min.js" ></script>
<script type="text/javascript">
    文档加载时,就执行 该函数
    $(function () {//这里是部门下拉框的数据显示
        //alert(11);
        $.ajax({
            url:'${pageContext.request.contextPath}/Servlet?method=findDepts',
            type:'get',
            dataType:'json',
            success:function (data) {   //data保存回调数据
                //alert(data);
                //[{},{},{}]
                $(data).each(function (index,item) {    // index索引 ,item 被查询出来的对象 dept
                    $("#dept").append("<option value='"+item.deptno+"'>"+item.dname+"</option>")
                });
            }

        });
    });
   
    //列表的删除
    function del(id) {
        if(confirm("确认删除吗")){
            window.location.href="${pageContext.request.contextPath}/Servlet?method=del&id="+id;
        }
    }
</script>
</html>

Servlet

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

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
   	request.setCharacterEncoding("UTF-8");
 	EmpService es=new EmpServiceImpl();
	//查询所有部门的数据
	List<Dept> d=es.fineD();//这里在数据库里获取所有部门信息，用于部门下拉显示
	String json = JSON.toJSONString(d);
	//将json写入客户端
	PrintWriter writer = response.getWriter();
	writer.print(json);//传到前端  
   }

DaoImpl

public List<Dept> findD() {
    Connection conn = db.getConnection();//获取数据库的信息
    List<Dept> depts=new ArrayList<>();//新建集合 用于接收部门信息
    try {
        PreparedStatement ps = conn.prepareStatement("select * FROM dept");//根据SQL查询部门表
        ResultSet rs = ps.executeQuery();
        while (rs.next()){
            Dept d=new Dept();
            d.setDeptno(rs.getInt("deptno"));
            d.setDname(rs.getString("dname"));
            d.setLoc(rs.getString("loc"));
            depts.add(d);
        }
        return depts;
    } catch (SQLException e) {
        e.printStackTrace();
    }
    return null;
}

以上做的是搜索框下拉选项的数据显示

以下是关于搜索的显示
     比如当只输入了名字没有选择部门(只根据姓名模糊查询)
     没有输入名字只选择了部门(只根据部门查找)
     两个都没有输入(查询所有)
     两个都输入(根据姓名和部门查找)

查询的Servlet

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

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        request.setCharacterEncoding("UTF-8");
        String name = request.getParameter("name");
        Integer deptno=Integer.valueOf(request.getParameter("deptno"));
        EmpService es=new EmpServiceImpl();
        boolean b = StrUtil.isEmpty(name);//判断字符串name是否为空 如果为空返回true 不为空返回false
        if(b==true&&deptno==0){//搜索框都为空时，搜索全部
            //这里直接调用的查询所有的Servlet
            request.getRequestDispatcher("/Servlet?method=login").forward(request,response);
        }else if (b==false&&deptno==0){//根据名字搜索
           List<Emp> list= es.findByEname(name);//查询方法
           //将数据传到前台
            request.setAttribute("emps",list);
            //跳转的页面
            request.getRequestDispatcher("WEB-INF/jsp/elist.jsp").forward(request,response);
        }else if(b==true&&deptno>0){//根据deptno搜索
            List<Emp> list= es.findByDeptno(deptno);
            //将数据传到前台
            request.setAttribute("emps",list);
             //跳转的页面
            request.getRequestDispatcher("WEB-INF/jsp/elist.jsp").forward(request,response);
        }else{//两个都输入
            List<Emp> list= es.findByAll(name,deptno);
            //将数据传到前台
            request.setAttribute("emps",list);
             //跳转的页面
            request.getRequestDispatcher("WEB-INF/jsp/elist.jsp").forward(request,response);
        }

    }

}

DaoImpl
根据名字模糊查询

/**
 * 根据名字进行模糊查询
 * 搜索框的搜索名字
 * @param name
 * @return
 */
@Override
public List<Emp> findByEname(String name) {
    Connection conn = db.getConnection();
    List<Emp> emps=new ArrayList<>();
    try {
        PreparedStatement ps = conn.prepareStatement("select * from emp e,dept d where e.deptno=d.deptno and e.ename like ?");
        ps.setString(1,"%"+name+"%");
        ResultSet rs = ps.executeQuery();
        while (rs.next()){
            System.out.println();
            Emp e=new Emp();
            e.setEmpno(rs.getInt("empno"));
            e.setEname(rs.getString("ename"));
            e.setJob(rs.getString("job"));

            Dept d=new Dept();
            d.setDeptno(rs.getInt("deptno"));
            d.setDname(rs.getString("dname"));

            e.setDept(d);
            emps.add(e);
        }
        return emps;
    } catch (SQLException e) {
        e.printStackTrace();
    }

    return null;
}

根据部门id查询

/**
 * 根据部门的id进行查询
 * 用于搜索框
 * @param deptno
 * @return
 */
@Override
public List<Emp> findByDeptno(Integer deptno) {
    Connection conn = db.getConnection();
    List<Emp> emps=new ArrayList<>();
    try {
        PreparedStatement ps = conn.prepareStatement("select * from emp e,dept d where e.deptno=d.deptno and d.deptno=?");
        ps.setInt(1,deptno);
        ResultSet rs = ps.executeQuery();
        while (rs.next()){
            System.out.println();
            Emp e=new Emp();
            e.setEmpno(rs.getInt("empno"));
            e.setEname(rs.getString("ename"));
            e.setJob(rs.getString("job"));

            Dept d=new Dept();
            d.setDeptno(rs.getInt("deptno"));
            d.setDname(rs.getString("dname"));

            e.setDept(d);
            emps.add(e);
        }
        return emps;
    } catch (SQLException e) {
        e.printStackTrace();
    }

    return null;
}

根据姓名和部门查找

/**
 * 根据部门和姓名查找
 * 用于搜索框回显
 * @param name
 * @param deptno
 * @return
 */
@Override
public List<Emp> findByAll(String name, Integer deptno) {
    Connection conn = db.getConnection();
    List<Emp> emps=new ArrayList<>();
    try {
        PreparedStatement ps = conn.prepareStatement("select * from emp e,dept d where e.deptno=d.deptno and e.ename like ? and d.deptno=?");
        ps.setString(1,"%"+name+"%");
        ps.setInt(2,deptno);
        ResultSet rs = ps.executeQuery();
        while (rs.next()){
            System.out.println();
            Emp e=new Emp();
            e.setEmpno(rs.getInt("empno"));
            e.setEname(rs.getString("ename"));
            e.setJob(rs.getString("job"));

            Dept d=new Dept();
            d.setDeptno(rs.getInt("deptno"));
            d.setDname(rs.getString("dname"));

            e.setDept(d);
            emps.add(e);
        }
        return emps;
    } catch (SQLException e) {
        e.printStackTrace();
    }

    return null;
}