Servlet之員工管理系統
阿新 • • 發佈：2021-01-11
目錄
1.專案結構
2.db.properties
連線資料庫
# database connection parameters driver=oracle.jdbc.driver.OracleDriver url=jdbc:oracle:thin:@localhost:1521:xe user=root pwd=root # datasource parameters init_size=1 max_size=3
3.WEB-INF下的web.xml
<servlet> <servlet-name>actionServlet</servlet-name> <servlet-class>web.ActionServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>actionServlet</servlet-name> <url-pattern>*.do</url-pattern> </servlet-mapping>
4.dao中的EmployeeDAO類
public class EmployeeDAO { public void save(Employee e){ Connection conn = null; try { conn = DBUtil.getConnection(); String sql = "INSERT INTO t_emp " + "VALUES(t_emp_seq.nextval,?,?,?)"; PreparedStatement ps = conn.prepareStatement(sql); ps.setString(1, e.getEname()); ps.setDouble(2, e.getSalary()); ps.setInt(3, e.getAge()); ps.executeUpdate(); } catch (SQLException e1) { //step1.記日誌（保留現場） e1.printStackTrace(); /* * step2.看異常能否恢復，如果不能夠 * 恢復(比如，資料庫服務暫停等，一般我們 * 稱之為系統異常)，要提示使用者稍後重試。 * 如果能夠恢復，則立即恢復。 */ throw new RuntimeException(e1); }finally{ DBUtil.close(conn); } } public List<Employee> findAll(){ List<Employee> employees = new ArrayList<Employee>(); Connection conn = null; try { conn = DBUtil.getConnection(); String sql = "SELECT * FROM t_emp"; PreparedStatement ps = conn.prepareStatement(sql); ResultSet rs = ps.executeQuery(); while(rs.next()){ Employee e = new Employee(); e.setId(rs.getInt("id")); e.setEname(rs.getString("ename")); e.setSalary(rs.getDouble("salary")); e.setAge(rs.getInt("age")); employees.add(e); } } catch (SQLException e) { e.printStackTrace(); throw new RuntimeException(e); }finally{ DBUtil.close(conn); } return employees; } public void delete(int id){ Connection conn = null; try { conn = DBUtil.getConnection(); String sql = "DELETE FROM t_emp WHERE id=?"; PreparedStatement ps = conn.prepareStatement(sql); ps.setInt(1, id); ps.executeUpdate(); } catch (SQLException e) { e.printStackTrace(); throw new RuntimeException(e); }finally{ DBUtil.close(conn); } } public Employee findById(int id){ Employee e = null; Connection conn = null; try { conn = DBUtil.getConnection(); String sql = "SELECT * FROM t_emp " + "WHERE id = ?"; PreparedStatement ps = conn.prepareStatement(sql); ps.setInt(1, id); ResultSet rs = ps.executeQuery(); if(rs.next()){ e = new Employee(); e.setId(id); e.setEname(rs.getString("ename")); e.setSalary(rs.getDouble("salary")); e.setAge(rs.getInt("age")); } } catch (SQLException e1) { e1.printStackTrace(); throw new RuntimeException(e1); }finally{ DBUtil.close(conn); } return e; } public void update(Employee e){ Connection conn = null; try { conn = DBUtil.getConnection(); String sql = "UPDATE t_emp SET ename=?," + "salary=?,age=? WHERE id=?"; PreparedStatement ps = conn.prepareStatement(sql); ps.setString(1, e.getEname()); ps.setDouble(2,e.getSalary()); ps.setInt(3, e.getAge()); ps.setInt(4, e.getId()); ps.executeUpdate(); } catch (SQLException e1) { e1.printStackTrace(); throw new RuntimeException(e1); }finally{ DBUtil.close(conn); } } }
5.entity中的Employee類
public class Employee {
private int id;
private String ename;
private double salary;
private int age;
@Override
public String toString() {
return "Employee [id=" + id
+ ", ename=" + ename
+ ", salary=" + salary + ", age=" + age + "]";
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getEname() {
return ename;
}
public void setEname(String ename) {
this.ename = ename;
}
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;
}
}6.util中的DBUtil類
public class DBUtil {
private static BasicDataSource ds;
static {
//載入引數
Properties p = new Properties();
try {
p.load(DBUtil.class.getClassLoader()
.getResourceAsStream("db.properties"));
//獲取這些引數
String driver = p.getProperty("driver");
String url = p.getProperty("url");
String user = p.getProperty("user");
String pwd = p.getProperty("pwd");
String initSize = p.getProperty("init_size");
String maxSize = p.getProperty("max_size");
//建立連線池
ds = new BasicDataSource();
//給它設定引數
ds.setDriverClassName(driver);
ds.setUrl(url);
ds.setUsername(user);
ds.setPassword(pwd);
ds.setInitialSize(Integer.parseInt(initSize));
ds.setMaxActive(Integer.parseInt(maxSize));
} catch (IOException e) {
e.printStackTrace();
throw new RuntimeException(
"載入db.properties失敗", e);
}
}
/**
* 由連線池建立的連線,其實現類由連線池提供.
*/
public static Connection getConnection()
throws SQLException {
return ds.getConnection();
}
/**
* 連線池提供的實現類,其close方法內部邏輯是,
* 將連線歸還給連線池,即它會清空連線物件中的資料,
* 並且將連線標記為空閒態.
*/
public static void close(Connection conn) {
if(conn != null) {
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
throw new RuntimeException(
"歸還連線失敗", e);
}
}
}
public static void rollback(Connection conn) {
if(conn != null) {
try {
conn.rollback();
} catch (SQLException e) {
e.printStackTrace();
throw new RuntimeException(
"回滾事務失敗", e);
}
}
}
}7.web中對的ActionServlet類
public class ActionServlet extends HttpServlet{
public void service(
HttpServletRequest request,
HttpServletResponse response)
throws ServletException,IOException{
request.setCharacterEncoding("utf-8");
response.setContentType(
"text/html;charset=utf-8");
PrintWriter out = response.getWriter();
String uri = request.getRequestURI();
String action =
uri.substring(uri.lastIndexOf("/"),
uri.lastIndexOf("."));
System.out.println("action:" + action);
if("/list".equals(action)){
EmployeeDAO dao =
new EmployeeDAO();
try{
List<Employee> employees =
dao.findAll();
//step1.綁訂資料到request。
request.setAttribute("employees",
employees);
//step2.獲得轉發器
RequestDispatcher rd =
request.getRequestDispatcher(
"empList3.jsp");
//step3.轉發
rd.forward(request, response);
}catch(Exception e){
e.printStackTrace();
out.println("系統繁忙，稍後重試");
}
}else if("/add".equals(action)){
//處理 新增員工的請求
//讀取員工資訊
String ename =
request.getParameter("ename");
String salary =
request.getParameter("salary");
String age =
request.getParameter("age");
System.out.println(ename + " "
+ salary + " " + age);
//將員工資訊插入到資料庫
EmployeeDAO dao = new EmployeeDAO();
Employee e = new Employee();
e.setEname(ename);
e.setSalary(Double.parseDouble(salary));
e.setAge(Integer.parseInt(age));
try{
dao.save(e);
//重定向到員工列表
response.sendRedirect("list.do");
}catch(Exception e1){
e1.printStackTrace();
out.println("<h1>系統繁忙，稍後重試</h1>");
}
//容器會自動關閉out,這兒不呼叫out.close()也可以
out.close();
}
}
}8.hello.jsp
<%@ page import="java.util.*"
contentType="text/html;charset=utf-8"
pageEncoding="utf-8"%>
<html>
<head></head>
<body style="font-size:30px;">
待我長髮及腰,用來拖地可好 <br/>
current time:
<%
Date date = new Date();
out.println(date);
%>
<br/>
current time2: <%= new Date()%>
<%
for(int i = 0; i < 100; i ++){
out.println("Hello World<br/>");
}
%>
</body>
</html>date.jsp
<%@ page contentType="text/html; charset=utf-8"
pageEncoding="utf-8" %>
<%@ page import="java.util.*,java.text.*" %>
<html>
<head></head>
<body style="font-size:30px;">
今天是:
<%
Date date = new Date();
SimpleDateFormat sdf =
new SimpleDateFormat("yyyy-MM-dd");
%>
<%=sdf.format(date)%>
</body>
</html>empList1.jsp
<%@ page pageEncoding="utf-8"
contentType="text/html;charset=utf-8" %>
<%@ page import="entity.*,dao.*,java.util.*" %>
<html>
<head>
<style>
.row1{
background-color:#fff8dc;
}
.row2{
background-color:#f0f0f0;
}
</style>
</head>
<body style="font-size:30px;">
<table width="60%" border="1"
cellpadding="0" cellspacing="0">
<tr>
<td>ID</td><td>姓名</td>
<td>薪水</td><td>年齡</td>
</tr>
<%
EmployeeDAO dao = new EmployeeDAO();
List<Employee> employees =
dao.findAll();
for(int i = 0; i < employees.size(); i ++){
Employee e = employees.get(i);
%>
<tr class="row<%=(i % 2 + 1)%>">
<td><%=e.getId()%></td>
<td><%=e.getEname()%></td>
<td><%=e.getSalary()%></td>
<td><%=e.getAge()%></td>
</tr>
<%
}
%>
</table>
</body>
</html>empList2.jsp
<%@ page pageEncoding="utf-8"
contentType="text/html; charset=utf-8" %>
<%@ page import="java.util.*,java.text.*,dao.*,entity.*" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title>員工管理</title>
<link rel="stylesheet"
type="text/css" href="css/style.css" />
</head>
<body>
<div id="wrap">
<div id="top_content">
<div id="header">
<div id="rightheader">
<p>
<%
Date date = new Date();
SimpleDateFormat sdf =
new SimpleDateFormat("yyyy-MM-dd");
%>
<%=sdf.format(date)%>
<br />
</p>
</div>
<div id="topheader">
<h1 id="title">
<a href="#">main</a>
</h1>
</div>
<div id="navigation">
</div>
</div>
<div id="content">
<p id="whereami">
</p>
<h1>
員工列表
</h1>
<table class="table">
<tr class="table_header">
<td>
ID
</td>
<td>
姓名
</td>
<td>
薪水
</td>
<td>
年齡
</td>
<td>
操作
</td>
</tr>
<%
EmployeeDAO dao =
new EmployeeDAO();
List<Employee> employees =
dao.findAll();
for(int i = 0; i < employees.size(); i ++){
Employee e = employees.get(i);
%>
<tr class="row<%=(i % 2 + 1)%>">
<td>
<%=e.getId()%>
</td>
<td>
<%=e.getEname()%>
</td>
<td>
<%=e.getSalary()%>
</td>
<td>
<%=e.getAge()%>
</td>
<td>
<a href="emplist.html">刪除</a>
<a href="updateEmp.html">修改</a>
</td>
</tr>
<%
}
%>
</table>
<p>
<input type="button" class="button"
value="新增員工" onclick="location='addEmp.html'"/>
</p>
</div>
</div>
<div id="footer">
<div id="footer_bg">
[email protected]
</div>
</div>
</div>
</body>
</html>empList3.jsp
<%@ page pageEncoding="utf-8"
contentType="text/html; charset=utf-8" %>
<%@ page import="java.util.*,java.text.*,entity.*" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title>員工管理</title>
<link rel="stylesheet"
type="text/css" href="css/style.css" />
</head>
<body>
<div id="wrap">
<div id="top_content">
<div id="header">
<div id="rightheader">
<p>
<%
Date date = new Date();
SimpleDateFormat sdf =
new SimpleDateFormat("yyyy-MM-dd");
%>
<%=sdf.format(date)%>
<br />
</p>
</div>
<div id="topheader">
<h1 id="title">
<a href="#">main</a>
</h1>
</div>
<div id="navigation">
</div>
</div>
<div id="content">
<p id="whereami">
</p>
<h1>
員工列表
</h1>
<table class="table">
<tr class="table_header">
<td>
ID
</td>
<td>
姓名
</td>
<td>
薪水
</td>
<td>
年齡
</td>
<td>
操作
</td>
</tr>
<%
List<Employee> employees =
(List<Employee>)request.getAttribute(
"employees");
for(int i = 0; i < employees.size(); i ++){
Employee e = employees.get(i);
%>
<tr class="row<%=(i % 2 + 1)%>">
<td>
<%=e.getId()%>
</td>
<td>
<%=e.getEname()%>
</td>
<td>
<%=e.getSalary()%>
</td>
<td>
<%=e.getAge()%>
</td>
<td>
<a href="emplist.html">刪除</a>
<a href="updateEmp.html">修改</a>
</td>
</tr>
<%
}
%>
</table>
<p>
<input type="button" class="button"
value="新增員工" onclick="location='addEmp.html'"/>
</p>
</div>
</div>
<div id="footer">
<div id="footer_bg">
[email protected]
</div>
</div>
</div>
</body>
</html>