Jsp+Servlet实现员工的增删改查
Jsp+Servlet实现员工的增删改查
收获：
- 用一个Servlet和字符串匹配处理所有请求
- 转发是一件事情未做完，调用另外一个组件继续做；而重定向是一件事情已经做完，再做另外一件事情。
- 转发过程中涉及到的所有Web组件共享同一个request对象和response对象，数据的传递和共享就依赖request对象。
实体类Employee.java
package entity;
public class Employee {
private int id;
private String name; //姓名
private double salary; //薪水
private int age; //年龄
public Employee() {
super();
}
public Employee(int id, String name, double salary, int age) {
super();
this.id = id;
this.name = name;
this.salary = salary;
this.age = age;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public double getSalary() {
return salary;
}
public void setSalary(double salary) {
this.salary = salary;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
@Override
public String toString() {
return "ID为:"+id+",name:"+name+",salary:"+salary+",age:"+age;
}
}
dao层
DBUtil.java
package dao;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class DBUtil {
public static Connection getConnection() throws ClassNotFoundException, SQLException{
Class.forName("com.mysql.jdbc.Driver");
Connection con=DriverManager.getConnection("jdbc:mysql:///emp","root","123456");
return con;
}
public static void close(Connection con) throws SQLException{
if(con!=null){
con.close();
}
}
/*public static void main(String[] args) throws ClassNotFoundException, SQLException{
System.out.println(DBUtil.getConnection());
}*/
}
EmployeeDao.java
package dao;
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 entity.Employee;
public class EmployeeDao {
/**
* 查询所有
* @return
* @throws ClassNotFoundException
* @throws SQLException
*/
public List findAll() throws ClassNotFoundException, SQLException{
ArrayList emps=new ArrayList();
Connection con=null;
PreparedStatement ps=null;
ResultSet rs=null;
con=DBUtil.getConnection();
ps=con.prepareStatement("select * from t_emp");
rs=ps.executeQuery();
while(rs.next()){
Employee emp=new Employee(rs.getInt("id"),
rs.getString("name"),rs.getDouble("salary"),rs.getInt("age"));
emps.add(emp);
//System.out.println(emp);
}
DBUtil.close(con);
return emps;
}
//增加员工
public void save(Employee emp) throws ClassNotFoundException, SQLException{
Connection con=null;
PreparedStatement ps=null;
con=DBUtil.getConnection();
ps=con.prepareStatement("insert into t_emp(name,salary,age) values(?,?,?)");
ps.setString(1, emp.getName());
ps.setDouble(2, emp.getSalary());
ps.setInt(3, emp.getAge());
ps.executeUpdate();
DBUtil.close(con);
}
//删除员工
public void delete(int id) throws ClassNotFoundException, SQLException{
Connection con=null;
PreparedStatement ps=null;
con=DBUtil.getConnection();
String sql="delete from t_emp where id=?";
ps=con.prepareStatement(sql);
ps.setInt(1,id);
ps.executeUpdate();
DBUtil.close(con);
}
//修改员工信息
public void modify(Employee emp) throws ClassNotFoundException, SQLException{
Connection con=null;
PreparedStatement ps=null;
con=DBUtil.getConnection();
String sql="update t_emp set name=?,salary=?,age=? where id=?";
ps=con.prepareStatement(sql);
ps.setString(1, emp.getName());
ps.setDouble(2, emp.getSalary());
ps.setInt(3, emp.getAge());
ps.setInt(4, emp.getId());
ps.executeUpdate();
DBUtil.close(con);
}
//根据id查询员工
public Employee findById(int id) throws ClassNotFoundException, SQLException{
Connection con=null;
PreparedStatement ps=null;
ResultSet rs=null;
Employee emp=null;
con=DBUtil.getConnection();
String sql="select * from t_emp where id=?";
ps=con.prepareStatement(sql);
ps.setInt(1, id);
rs=ps.executeQuery();
if(rs.next()){
emp=new Employee(rs.getInt("id"),
rs.getString("name"),rs.getDouble("salary"),rs.getInt("age"));
}
DBUtil.close(con);
return emp;
}
}
ActionServlet .java
package web;
import java.io.IOException;
import java.sql.SQLException;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import dao.EmployeeDao;
import entity.Employee;
public class ActionServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
@Override
protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setContentType("text/html;charset=utf-8");
String uri=request.getRequestURI();
String action=uri.substring(uri.lastIndexOf("/")+1,uri.lastIndexOf("."));
EmployeeDao dao=new EmployeeDao();
if(action.equals("list")){
try {
List emps = dao.findAll();
request.setAttribute("emps", emps);
//转发
request.getRequestDispatcher("listEmp1.jsp").forward(request, response);
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
}else if(action.equals("add")){
String name=request.getParameter("name");
double salary=Double.valueOf(request.getParameter("salary"));
int age=Integer.valueOf(request.getParameter("age"));
Employee emp=new Employee();
emp.setName(name);
emp.setSalary(salary);
emp.setAge(age);
try {
dao.save(emp);
//重定向
response.sendRedirect("list.do");
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
}else if(action.equals("delete")){
int id = Integer.valueOf(request.getParameter("id"));
try {
dao.delete(id);
response.sendRedirect("list.do");
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}else if(action.equals("load")){
int id=Integer.valueOf(request.getParameter("id"));
try {
Employee emp = dao.findById(id);
request.setAttribute("emp", emp);
request.getRequestDispatcher("updateEmp.jsp").forward(request, response);
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
}else if(action.equals("update")){
int id=Integer.valueOf(request.getParameter("id"));
String name=request.getParameter("name");
double salary=Double.valueOf(request.getParameter("salary"));
int age=Integer.valueOf(request.getParameter("age"));
Employee emp=new Employee(id,name,salary,age);
try {
dao.modify(emp);
response.sendRedirect("list.do");
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
listEmp1.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ page import="dao.*,entity.*,java.util.*" %>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title heretitle>
<style>
.row1{
background-color:#E4E4E4;
}
.row2{
background-color:#FBD10A;
}
style>
head>
<body>
<table border="1" cellpadding="0">
<caption>员工信息caption>
<tr>
<td>编号td>
<td>姓名td>
<td>薪水td>
<td>年龄td>
<td>操作td>
tr>
<%
EmployeeDao dao=new EmployeeDao();
List emps=dao.findAll();
for(int i=0;iget (i);
%>
<tr class="row<%=i%2+1%>">
<td><%=emp.getId() %>td>
<td><%=emp.getName() %>td>
<td><%=emp.getSalary() %>td>
<td><%=emp.getAge() %>td>
<td>
<a href="delete.do?id=<%=emp.getId() %>" onclick="return confirm('是否确认删除<%=emp.getName() %>信息')">删除a>
<a href="load.do?id=<%=emp.getId()%>">修改a>
td>
tr>
<%} %>
table>
<p>
<input type="button" value="增加员工" onclick="location='addEmp.jsp'"/>
p>
body>
html>addEmp.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>添加员工title>
head>
<body>
<form action="add.do">
姓名:<input type="text" name="name"/><br/>
薪水:<input type="text" name="salary"/><br/>
年龄:<input type="text" name="age"/><br/>
<input type="submit" value="增加"/>
form>
body>
html>updateEmp.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ page import="dao.*,entity.*,java.util.*" %>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>修改员工信息title>
head>
<body>
<%
Employee emp=(Employee)request.getAttribute("emp");
%>
<form action="update.do?id=<%=emp.getId()%>" method="post">
<table border="1px">
<tr>
<td>编号td>
<td>
<input type="text" name="id" value="<%=emp.getId()%>"/>
td>
tr>
<tr>
<td>姓名td>
<td>
<input type="text" name="name" value="<%=emp.getName()%>"/>
td>
tr>
<tr>
<td>薪水td>
<td>
<input type="text" name="salary" value="<%=emp.getSalary()%>"/>
td>
tr>
<tr>
<td>年龄td>
<td>
<input type="text" name="age" value="<%=emp.getAge()%>"/>
td>
tr>
table>
<p>
<input type="submit" value="修改"/>
p>
form>
body>
html>web.xml
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
<display-name>Jsp01display-name>
<welcome-file-list>
<welcome-file>listEmp1.jspwelcome-file>
welcome-file-list>
<servlet>
<servlet-name>actionServletservlet-name>
<servlet-class>web.ActionServletservlet-class>
servlet>
<servlet-mapping>
<servlet-name>actionServletservlet-name>
<url-pattern>*.dourl-pattern>
servlet-mapping>
web-app>