项目实战之使用Servlet+JSP+XML(EL表达式版)实现联系人功能

最新推荐文章于 2022-09-24 21:40:33 发布

evan_qb

最新推荐文章于 2022-09-24 21:40:33 发布

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分类专栏： Java学习 # javaweb 文章标签： jsp

本文链接：https://blog.youkuaiyun.com/Evan_QB/article/details/76356913

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首先我们应该用对其分包，如下图

首先，我们先创建一个Contact实体类

package cn.qblank.entity;

public class Contact {
	private String id;
	private String name;
	private int age;
	private String gender;
	private String qq;
	private String phone;
	private String address;
	public String getPhone() {
		return phone;
	}
	public void setPhone(String phone) {
		this.phone = phone;
	}
	public String getId() {
		return id;
	}
	public void setId(String id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
	public String getGender() {
		return gender;
	}
	public void setGender(String gender) {
		this.gender = gender;
	}
	public String getQq() {
		return qq;
	}
	public void setQq(String qq) {
		this.qq = qq;
	}
	public String getAddress() {
		return address;
	}
	public void setAddress(String address) {
		this.address = address;
	}
	public Contact(String id, String name, int age, String gender, String qq,
			String address) {
		super();
		this.id = id;
		this.name = name;
		this.age = age;
		this.gender = gender;
		this.qq = qq;
		this.address = address;
	}
	public Contact() {
		super();
	}
	@Override
	public String toString() {
		return "Contact [id=" + id + ", name=" + name + ", age=" + age
				+ ", gender=" + gender + ", qq=" + qq + ", address=" + address
				+ "]";
	}
	
	
}

然后建立一个contact.xml在F盘

写一个XMLUtil类对xml的优化xml的读取和修改

package cn.qblank.utl;

import java.io.File;
import java.io.FileOutputStream;

import org.dom4j.Document;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;

public class XMLUtil {
	/**
	 * 获取结点
	 * @return
	 * @throws Exception
	 */
	public static Document getDocuement() throws Exception{
		return new SAXReader().read(new File("F:/contact.xml"));
	}
	
	/**
	 * 写入文档
	 */
	public static void writeXml(Document doc){
		try {
			FileOutputStream out = new FileOutputStream("F:/contact.xml");
			OutputFormat format = OutputFormat.createPrettyPrint();
			format.setEncoding("utf-8");
			XMLWriter writer = new XMLWriter(out,format);
			writer.write(doc);
			writer.close();
		} catch (Exception e) {
			e.printStackTrace();
			throw new RuntimeException(e);
		}
	}
	
}

下面开始写dao层的代码

先实现一个查询所有联系人的功能

@Override
	public List<Contact> listAllContact() throws Exception {
		Document doc = XMLUtil.getDocuement();
		List<Contact> list = new ArrayList<>();
		@SuppressWarnings("unchecked")
		List<Element> contactList= (List<Element>)doc.selectNodes("//contact");
		for (Element elem : contactList) {
			Contact contact = new Contact();
			contact.setId(elem.attributeValue("id"));
			contact.setName(elem.elementText("name"));
			contact.setAge(Integer.parseInt(elem.elementText("age")));
			contact.setGender(elem.elementText("gender"));
			contact.setQq(elem.elementText("qq"));
			contact.setPhone(elem.elementText("phone"));
			contact.setAddress(elem.elementText("address"));
			list.add(contact);
		}
		
		return list;
	}

对应的Servlet（接收数据）代码和Jsp(显示界面)代码如下

public class AddContactServlet extends HttpServlet {
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException {
		req.setCharacterEncoding("utf-8");
		resp.setContentType("text/html;charset=utf-8");
		resp.setCharacterEncoding("utf-8");
		//获取参数
		String name = req.getParameter("c_name");
		int age = Integer.parseInt(req.getParameter("c_age"));
		String gender = req.getParameter("c_gender");
		String qq = req.getParameter("c_qq");
		String phone = req.getParameter("c_phone");
		String address = req.getParameter("c_address");
		
		Contact contact = new Contact();
		contact.setName(name);
		contact.setAge(age);
		contact.setGender(gender);
		contact.setQq(qq);
		contact.setPhone(phone);
		contact.setAddress(address);
		
		ContactDaoImpl contactDaoImpl = new ContactDaoImpl();
		contactDaoImpl.addContact(contact);
		resp.sendRedirect(req.getContextPath() + "/ListContactServlet");
	}
	
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException {
		doGet(req, resp);
	}
}

JSP代码如下:

<%@ page language="java"
		 import="java.util.*,cn.qblank.entity.*" 
		 pageEncoding="UTF-8"%>
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>联系人列表</title>
    
	<meta http-equiv="pragma" content="no-cache">
	<meta http-equiv="cache-control" content="no-cache">
	<meta http-equiv="expires" content="0">    
	<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
	<meta http-equiv="description" content="This is my page">
  </head>
  <style>
  		body{
  			text-align:center;
  		}
  
  		table{
  			width:1000px;
  			text-align:center;
  			margin: 0 auto;
  		}
  </style>
  <body>
  		<h1>查询所有联系人</h1>
  		<table border="1" cellspacing="0"> 
  			<tr>
  				<th>编号</th>
  				<th>姓名</th>
  				<th>年龄</th>
  				<th>性别</th>
  				<th>qq</th>
  				<th>phone</th>
  				<th>address</th>
  				<th colspan="2">操作</th>
  			</tr>
  			<!-- 接收到ListContactServlet发过来的信息 -->
  			 <c:forEach items="${contacts}" var="contact">
  			 <c:if test="${!empty contact}">
  			 	<tr>
  			 		<td>${contact.id}</td>
  			 		<td>${contact.name }</td>
  			 		<td>${contact.age }</td>
  			 		<td>${contact.gender}</td>
  			 		<td>${contact.qq}</td>
  			 		<td>${contact.phone}</td>
  			 		<td>${contact.address}</td>
  			 		<td><a href="/ContactProject/QueryContactServlet?id=${contact.id}">修改</a></td>
  			 		<td><a href="/ContactProject/DeleteContactServlet?id= ${contact.id}">删除</a></td>
  			 	</tr>
  			 </c:if>
  			 </c:forEach>
  			 
  			 
  			 <tr>
    				<td colspan="9" align="center"><a href="add_contact.html">[添加联系人]</a></td>
    		</tr>
  		</table>
  		
  </body>
</html>

然后再实现一个增加联系人的功能,我们使用UUID的randomUUID方法产生唯一id

public void addContact(Contact contact) {
		
		File file = new File("F://contact.xml");
		Document doc = null;
		Element rootElem = null;
		try {
			if (!file.exists()) {
				doc = DocumentHelper.createDocument();
				rootElem = doc.addElement("contactList");
			}else{
					doc = XMLUtil.getDocuement();
					rootElem = doc.getRootElement();
			}
			//添加联系人
			Element contactElem = rootElem.addElement("contact");
			/**
			 * UUid
			 */
			String uuid = UUID.randomUUID().toString().replace("-", "");
			contactElem.addAttribute("id", uuid);
			contactElem.addElement("name").setText(contact.getName());
			contactElem.addElement("age").setText(contact.getAge()+"");
			contactElem.addElement("gender").setText(contact.getGender());
			contactElem.addElement("qq").setText(contact.getQq());
			contactElem.addElement("phone").setText(contact.getPhone());
			contactElem.addElement("address").setText(contact.getAddress());
			
			//写入文档
			XMLUtil.writeXml(doc);
			
		} catch (Exception e) {
			e.printStackTrace();
		}
		
	}

然后写一个add_contact.html页面,显示添加联系人的界面

<style>
  		
  		
  		table{
  			margin:0 auto;
  		}
  		
  		table tr td{
  			margin-left:20px;
  		}
  		
  		h1{
  			text-align:center;
  		}
  </style>
  <body>
  		<h1>添加联系人</h1>
  		<form action="/ContactProject/AddContactServlet"  method="post">
  			<table border="1">
  			<tr>
  				<td>姓名</td>
  				<td><input type="text" name="c_name"/></td>
  			</tr>
  			<tr>
  				<td>年龄</td>
  				<td><input type="text" name="c_age"/></td>
  			</tr>
  			<tr>
  				<td>性别</td>
  				<td>
  					男<input type="radio" name="c_gender"/>
  					女<input type="radio" name="c_gender"/>
  				</td>
  			</tr>
  			<tr>
  				<td>qq</td>
  				<td><input type="text" name="c_qq"/></td>
  			</tr>
  			<tr>
  				<td>电话</td>
  				<td><input type="text" name="c_phone"/></td>
  			</tr>
  			<tr>
  				<td>地址</td>
  				<td><input type="text" name="c_address"/></td>
  			</tr>
  			<tr>
  				<td colspan="2" style="text-align:center">
  					<input type="submit" value="保存"/>
  					<input type="reset" value="重置"/>
  				</td>
  			</tr>
  		</table>
  	</form>
  </body>

然后对应的写一个Servlet用于接收用户输入的信息，并调用dao层的添加方法，将其输入的信息导入xml中

public class AddContactServlet extends HttpServlet {
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException {
		req.setCharacterEncoding("utf-8");
		resp.setContentType("text/html;charset=utf-8");
		resp.setCharacterEncoding("utf-8");
		//获取参数
		String name = req.getParameter("c_name");
		int age = Integer.parseInt(req.getParameter("c_age"));
		String gender = req.getParameter("c_gender");
		String qq = req.getParameter("c_qq");
		String phone = req.getParameter("c_phone");
		String address = req.getParameter("c_address");
		
		Contact contact = new Contact();
		contact.setName(name);
		contact.setAge(age);
		contact.setGender(gender);
		contact.setQq(qq);
		contact.setPhone(phone);
		contact.setAddress(address);
		
		ContactDaoImpl contactDaoImpl = new ContactDaoImpl();
		contactDaoImpl.addContact(contact);
		resp.sendRedirect(req.getContextPath() + "/ListContactServlet");
	}
	
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException {
		doGet(req, resp);
	}
}

下面是删除功能，删除功能最重要的一点是获取id,那么怎么才能获取到id呢，我们可以在主界面contact_list.jsp的删除链接跳转时将id这个参数传入过去,如上contact_list.jsp

<td><a href="/ContactProject/DeleteContactServlet?id= <%=contact.getId().trim() %>">删除</a></td>

然后对应的Servlet接收这个id

public class DeleteContactServlet extends HttpServlet {
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException {
		ContactDaoImpl contactDaoImpl = new ContactDaoImpl();
		String id = req.getParameter("id");
		contactDaoImpl.deleteContact(id);
		resp.sendRedirect(req.getContextPath() + "/ListContactServlet");
		
	}
	
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException {
		doGet(req, resp);
	}
}

然后在dao层，将对应的联系人删除

@Override
	public void deleteContact(String id) {
		Document doc = null;
		try {
			doc = XMLUtil.getDocuement();
			Element contactElem = (Element) doc.selectSingleNode("//contact[@id='"+id.trim()+"']");
			if (contactElem != null) {
				contactElem.detach();
			}
			XMLUtil.writeXml(doc);
			
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

接下来，就是修改的操作，该操作同样需要拿到id，我们也可以用同样的方式接收id

<td><a href="/ContactProject/QueryContactServlet?id=<%=contact.getId()%>">修改</a></td>

由于原本的数据不能变，所以我们需要将原本的数据先查出来，然后才能继续进行修改

@Override
public Contact findById(String id) {
	Document doc = null;
	Contact c = null;
	try {
		doc = XMLUtil.getDocuement();
		Element contactElem = (Element)doc.selectSingleNode("//contact[@id='"+id+"']");
		if (contactElem != null) {
			c  = new Contact();
			c.setId(contactElem.attributeValue("id"));
			c.setName(contactElem.elementText("name"));
			c.setAge(Integer.parseInt(contactElem.elementText("age")));
			c.setGender(contactElem.elementText("gender"));
			c.setQq(contactElem.elementText("qq"));
			c.setPhone(contactElem.elementText("phone"));
			c.setAddress(contactElem.elementText("address"));
		}
			
	} catch (Exception e) {
		e.printStackTrace();
	}
		
	return c;
}

然后写一个QueryContactServlet用于接收查到的数据

public class QueryContactServlet extends HttpServlet {
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException {
		req.setCharacterEncoding("utf-8");
		resp.setContentType("text/html;charset=utf-8");
		resp.setCharacterEncoding("utf-8");
		String id = req.getParameter("id").trim();
		//通过id查询到联系人
		ContactDaoImpl contactDaoImpl = new ContactDaoImpl();
		Contact contact = contactDaoImpl.findById(id);
		req.setAttribute("contact", contact);
		req.getRequestDispatcher("update_contact.jsp").forward(req, resp);
	}
	
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException {
		doGet(req, resp);
	}
}

接下来就是用update_contact.jsp，显示原来的数据

<style>
  		table{
  			margin:0 auto;
  		}
  		
  		table tr td{
  			margin-left:20px;
  		}
  		
  		h1{
  			text-align:center;
  		}
  </style>
  <body>
    	<h1>修改联系人</h1>
    	
    
  		<form action="/ContactProject/UpdateContactServlet" method="post">
	  		<%
	    		Contact contact = (Contact)request.getAttribute("contact");
	    	 %>
	    
  			<input type="hidden" name="id" value="${contact.id}">
  			<table border="1">
  			<tr>
  				<td>姓名</td>
  				<td><input type="text" name="c_name" value="${contact.name}"/></td>
  			</tr>
  			<tr>
  				<td>年龄</td>
  				<td><input type="text" name="c_age" value="${contact.age}"/></td>
  			</tr>
  			<tr>
  				<td>性别</td>
  				<td>
  					男<input type="radio" name="c_gender" value="男" <c:if test="${contact.gender == '男'}">checked</c:if> />
  					女<input type="radio" name="c_gender" value="女" <c:if test="${contact.gender == '女'}">checked</c:if> />
  				</td>
  			</tr>
  			<tr>
  				<td>qq</td>
  				<td><input type="text" name="c_qq" value="${contact.qq}"/></td>
  			</tr>
  			<tr>
  				<td>电话</td>
  				<td><input type="text" name="c_phone" value="${contact.phone}"/></td>
  			</tr>
  			<tr>
  				<td>地址</td>
  				<td><input type="text" name="c_address" value="${contact.address}"/></td>
  			</tr>
  			<tr>
  				<td colspan="2" style="text-align:center">
  					<input type="submit" value="保存"/>
  					<input type="reset" value="重置"/>
  				</td>
  			</tr>
  		</table>
  	</form>
  </body>

接下来根据用户修改的数据进行修改,方法和添加类似

public class UpdateContactServlet extends HttpServlet {
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException {
		req.setCharacterEncoding("utf-8");
		resp.setContentType("text/html;charset=utf-8");
		resp.setCharacterEncoding("utf-8");
		//获取参数
		String id = req.getParameter("id");
		String name = req.getParameter("c_name");
		int age = Integer.parseInt(req.getParameter("c_age"));
		String gender = req.getParameter("c_gender");
		String qq = req.getParameter("c_qq");
		String phone = req.getParameter("c_phone");
		String address = req.getParameter("c_address");
		
		Contact contact = new Contact();
		contact.setId(id);
		contact.setName(name);
		contact.setAge(age);
		contact.setGender(gender);
		contact.setQq(qq);
		contact.setPhone(phone);
		contact.setAddress(address);
		ContactDaoImpl contactDaoImpl = new ContactDaoImpl();
		contactDaoImpl.updateContact(contact);
		//3.跳转到查询联系人的页面
		resp.sendRedirect(req.getContextPath()+"/ListContactServlet");
	}
	
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException {
		doGet(req, resp);
	}
}

对应的dao层修改数据

@Override
	public void updateContact(Contact contact) {
		Document doc = null;
		try {
			doc = XMLUtil.getDocuement();
			Element contactElem = (Element) doc.selectSingleNode("//contact[@id='"+contact.getId()+"']");
			contactElem.element("name").setText(contact.getName());
			contactElem.element("age").setText(contact.getAge()+"");
			contactElem.element("gender").setText(contact.getGender());
			contactElem.element("qq").setText(contact.getQq());
			contactElem.element("phone").setText(contact.getPhone());
			contactElem.element("address").setText(contact.getAddress());
			//写入文档
			XMLUtil.writeXml(doc);
		} catch (Exception e) {
			e.printStackTrace();
		}
		
	}

这样，我们利用xml实现增删改查的功能就实现了，总结一点

在这个我们用到了Servlet，JSP，XMl技术,EL表达式

Servlet：用于接收数据，并处理逻辑

JSP : 用于显示界面,和用户进行交互,在jsp中尽量少写java代码

XML : 用于存储数据，实现持久化数据，类似于数据库。