大家好，我是雄雄，今天分享的技术很简单，即ajax结合jdbc动态实现及时刷新表单数据。
前言：相信大家在网上冲浪的时候，肯定会发现这样的场景，在实现某个查询功能时，下方表格中会显示需要展示的结果，当查询条件换掉之后，数据表格中显示的信息也会及时更新，今天，我们就来实现一下这样的功能。
效果图如下所示：
数据库：mysql
开发编辑器：myeclipse
浏览器：chrome
采用java三层架构分层开发，首先我们先来看看数据库的表结构：
Emp表：
Dept表：
接下来就是按照表结构写实体类，代码如下：
Emp实体类：
package org.entity;
public class Emp {
private int eid;
private String ename;
private String epass;
private int edid;
private Dept dept;
public Dept getDept() {
return dept;
}
public void setDept(Dept dept) {
this.dept = dept;
}
public int getEid() {
return eid;
}
public void setEid(int eid) {
this.eid = eid;
}
public String getEname() {
return ename;
}
public void setEname(String ename) {
this.ename = ename;
}
public String getEpass() {
return epass;
}
public void setEpass(String epass) {
this.epass = epass;
}
public int getEdid() {
return edid;
}
public void setEdid(int edid) {
this.edid = edid;
}
public Emp( String ename, String epass, int edid) {
super();
this.ename = ename;
this.epass = epass;
this.edid = edid;
}
public Emp(){
}
}Dept实体类：
package org.entity;
public class Emp {
private int eid;
private String ename;
private String epass;
private int edid;
private Dept dept;
public Dept getDept() {
return dept;
}
public void setDept(Dept dept) {
this.dept = dept;
}
public int getEid() {
return eid;
}
public void setEid(int eid) {
this.eid = eid;
}
public String getEname() {
return ename;
}
public void setEname(String ename) {
this.ename = ename;
}
public String getEpass() {
return epass;
}
public void setEpass(String epass) {
this.epass = epass;
}
public int getEdid() {
return edid;
}
public void setEdid(int edid) {
this.edid = edid;
}
public Emp( String ename, String epass, int edid) {
super();
this.ename = ename;
this.epass = epass;
this.edid = edid;
}
public Emp(){
}
}连接数据库所需的BaseDao：
package org.entity;
public class Emp {
private int eid;
private String ename;
private String epass;
private int edid;
private Dept dept;
public Dept getDept() {
return dept;
}
public void setDept(Dept dept) {
this.dept = dept;
}
public int getEid() {
return eid;
}
public void setEid(int eid) {
this.eid = eid;
}
public String getEname() {
return ename;
}
public void setEname(String ename) {
this.ename = ename;
}
public String getEpass() {
return epass;
}
public void setEpass(String epass) {
this.epass = epass;
}
public int getEdid() {
return edid;
}
public void setEdid(int edid) {
this.edid = edid;
}
public Emp( String ename, String epass, int edid) {
super();
this.ename = ename;
this.epass = epass;
this.edid = edid;
}
public Emp(){
}
}接着，就是Dao层接口，IEmpDao：
package org.entity;
public class Emp {
private int eid;
private String ename;
private String epass;
private int edid;
private Dept dept;
public Dept getDept() {
return dept;
}
public void setDept(Dept dept) {
this.dept = dept;
}
public int getEid() {
return eid;
}
public void setEid(int eid) {
this.eid = eid;
}
public String getEname() {
return ename;
}
public void setEname(String ename) {
this.ename = ename;
}
public String getEpass() {
return epass;
}
public void setEpass(String epass) {
this.epass = epass;
}
public int getEdid() {
return edid;
}
public void setEdid(int edid) {
this.edid = edid;
}
public Emp( String ename, String epass, int edid) {
super();
this.ename = ename;
this.epass = epass;
this.edid = edid;
}
public Emp(){
}
}接口实现类EmpDaoImpl：
package org.dao.impl;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import org.dao.BaseDao;
import org.dao.IEmpDao;
import org.entity.Dept;
import org.entity.Emp;
import com.sun.corba.se.spi.orbutil.fsm.Guard.Result;
public class EmpDaoImpl implements IEmpDao {
private Connection conn;
private PreparedStatement p;
private ResultSet rs;
BaseDao base = new BaseDao();
@Override
public int addEmp(Emp emp) {
String sql = "insert into Emp(ename,epass,edid) values(?,?,?);";
List<Object> prama = new ArrayList<Object>();
prama.add(emp.getEname());
prama.add(emp.getEpass());
prama.add(emp.getEdid());
int rel = 0;
try {
rel = base.ExecuteUpdate(sql, prama);
} catch (SQLException e) {
e.printStackTrace();
}finally{
base.closeConn(conn, p, rs);
}
return rel;
}
//查询全部
@Override
public List<Emp> findEmpAll() {
String sql = "SELECT * FROM emp ,dept WHERE emp.edid = dept.did";
List<Emp> eList = new ArrayList<Emp>();
try {
rs = base.ExecuteQuery(sql, null);
while(rs.next()){
Emp emp = new Emp();
emp.setEid(rs.getInt("eid"));
emp.setEname(rs.getString("ename"));
emp.setEpass(rs.getString("epass"));
emp.setEdid(rs.getInt("edid"));
Dept dept = new Dept();
dept.setDid(rs.getInt("did"));
dept.setDname(rs.getString("dname"));
emp.setDept(dept);
eList.add(emp);
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
base.closeConn(conn, p, rs);
}
return eList;
}
@Override
public int delEmp(int eid) {
String sql = "delete from emp where eid = ?;";
List<Object> prama = new ArrayList<Object>();
prama.add(eid);
int rel = 0;
try {
rel = base.ExecuteUpdate(sql, prama);
} catch (SQLException e) {
e.printStackTrace();
}finally{
base.closeConn(conn, p, rs);
}
return rel;
}
@Override
public Emp findEmpByName(String name) {
String sql = "select * from Emp where ename =?";
List<Object> pa= new ArrayList<Object>();
pa.add(name);
Emp emp = new Emp();
try {
rs = base.ExecuteQuery(sql, pa);
while(rs.next()){
emp.setEid(rs.getInt("eid"));
emp.setEname(rs.getString(2));
emp.setEpass(rs.getString(3));
emp.setEdid(rs.getInt("edid"));
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
base.closeConn(conn, p, rs);
}
return emp;
}
//根据部门编号查询
@Override
public List<Emp> findEmpByDid(int edid) {
List<Emp> empList = new ArrayList<Emp>();
List<Object> param = new ArrayList<Object>();
String sql = null;
if(edid!=0){
sql = "SELECT * FROM emp ,dept WHERE emp.edid = dept.did and edid = ?";
param.add(edid);
}else{
sql = "SELECT * FROM emp ,dept WHERE emp.edid = dept.did";
}
try {
rs = base.ExecuteQuery(sql, param);
while(rs.next()){
Emp emp = new Emp();
emp.setEid(rs.getInt("eid"));
emp.setEname(rs.getString("ename"));
emp.setEpass(rs.getString("epass"));
emp.setEdid(rs.getInt("edid"));
Dept dept = new Dept();
dept.setDid(rs.getInt("did"));
dept.setDname(rs.getString("dname"));
emp.setDept(dept);
empList.add(emp);
}
} catch (SQLException e) {
e.printStackTrace();
}finally{
base.closeConn(conn, p, rs);
}
return empList;
}
}Service层接口IEmpService：
package org.service;
import org.dao.IEmpDao;
public interface IEmpService extends IEmpDao {
}Service层实现类：EmpServiceImpl:
package org.service.impl;
import java.util.List;
import org.dao.IEmpDao;
import org.dao.impl.EmpDaoImpl;
import org.entity.Emp;
import org.service.IEmpService;
public class EmpServiceImpl implements IEmpService {
IEmpDao empDao = new EmpDaoImpl();
@Override
public int addEmp(Emp emp) {
return empDao.addEmp(emp);
}
@Override
public List<Emp> findEmpAll() {
// TODO Auto-generated method stub
return empDao.findEmpAll();
}
@Override
public int delEmp(int eid) {
// TODO Auto-generated method stub
return empDao.delEmp(eid);
}
@Override
public Emp findEmpByName(String name) {
// TODO Auto-generated method stub
return empDao.findEmpByName(name);
}
@Override
public List<Emp> findEmpByDid(int edid) {
return empDao.findEmpByDid(edid);
}
}主要内容在前台jsp页面，我们先来写一个下拉列表，用来存放Dept表中的所有部门名称，当加载该jsp页面时，先从数据库中查询所有部门名称，然后通过jstl遍历至下拉列表中。代码如下：
<%
IEmpService empService = new EmpServiceImpl();
List<Emp> empList = empService.findEmpAll();
request.setAttribute("empList", empList);
IDeptService deptService = new DeptServiceImpl();
List<Dept> deptList = deptService.findAllDept();
request.setAttribute("deptList", deptList);
%>部门编号：
<!-- <input type="text" name="edid"/> -->
<select id="deptid">
<option value="0">全部</option>
<c:forEach items="${deptList }" var="dept">
<option value="${dept.did }">${dept.dname }</option>
</c:forEach>
</select>
<input type="button" id="serch" value="查询"/>当点击查询按钮时，通过ajax去Servlet中，根据部门编号查询员工信息，在回调函数（success）中处理返回的json数据，遍历动态添加至表格中。
“查询”按钮 的点击事件：
//点击查询查询值
$("#serch").click(function(){
//获取部门编号
//var edid = $("input[name='edid']").val();
//获取下拉列表中的值
var edid = $("#deptid").val();
var data = {"edid":edid,"tag":"getEmpByEdid"};
$.getJSON("EmpServlet",data,function(data){
$("#dataTable").html("<tr><td>编号</td><td>姓名</td><td>密码</td><td>部门编号</td><td>操作</td></tr>");
for(var i in data){
//给表格中添加数据
$("#dataTable").append("<tr><td>"
+data[i].eid+"</td><td>"
+data[i].ename+"</td><td>"
+data[i].epass+"</td><td>"
+data[i].dept.dname+"</td><td><a href='EmpServlet?tag=del&eid="+data[i].eid+"'>删除</a></td></tr>");
}
});
});数据表格的代码：
<table border="1" id="dataTable">
<tr>
<td>编号</td>
<td>姓名</td>
<td>密码</td>
<td>部门名称</td>
<td>操作</td>
</tr>
<c:forEach items="${empList }" var="emp">
<tr>
<td>${emp.eid }</td>
<td>${emp.ename }</td>
<td>${emp.epass}</td>
<td>${emp.dept.dname}</td>
<td>
<a href="EmpServlet?tag=del&eid=${emp.eid }">删除</a>
</td>
</tr>
</c:forEach>
</table>Servlet类中关键代码：
//根据部门编号查询信息
public void getEmpByEdid(HttpServletRequest request, HttpServletResponse response) throws IOException{
Integer edid = Integer.parseInt(request.getParameter("edid"));
List<Emp> emplist = empService.findEmpByDid(edid);
String jsonresult = JSON.toJSONString(emplist);
System.out.println(jsonresult);
PrintWriter out = response.getWriter();
out.print(jsonresult);
}基本思路就是这样的，怎么样，是不是很简单？
需要辣椒酱的可以在小商店中直接下单哦~
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