JavaBean

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一.JavaBean概述 

二.JavaBean种类 

index.jsp 

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<form action="result.jsp" method="post">
	<table width="250px" height="100px" border="1px" align="center">
		<tr>
			<td colspan="2" align="center">
				 <b>登录页面</b>
			</td>
		</tr>
		<tr>
			<td >用户名：</td>
			<td>
				<input type="text" name="username">
			</td>
		</tr>
		<tr>
			<td >密码：</td>
			<td>
				<input type="password" name="password">
			</td>
		</tr>
		<tr>
			<td colspan="2" align="center">
				<input type="submit">
			</td>
		
		</tr>
	</table>
 
</form>

</body>
</html>

result.jsp 

<%@ page import="model.User" %>
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
    
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<div align="center">
	<%
		String username= request.getParameter("username");
		String password= request.getParameter("password");
		//将数据封装到Javabean中
		User user=new User(username,password);
		if("admin".equals(user.getUsename())&&"123456".equals(user.getPossword()))
			out.print("登录成功");
			
			
		else
			out.print("登录失败");
		
	%>
	<br>
	<a href="index.jsp">返回</a>
</div>
</body>
</html>

User.java 

package model;
public class User 
	private String usename;
	private String possword;
	
	public User(String usename, String possword) 
		super();
		this.usename = usename;
		this.possword = possword;
	
	public String getUsename() 
		return usename;
	
	public void setUsename(String usename) 
		this.usename = usename;
	
	public String getPossword() 
		return possword;
	
	public void setPossword(String possword) 
		this.possword = possword;

三.JavaBean的应用

3.1获取JavaBean属性信息

如果写的类有初始值可以用getProperty获取 

stuInfo.jsp 

<%@page import="model.Student" %>
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<!-- 使用JavaBean 并设置id -->
<jsp:useBean id="stu" class="model.Student"></jsp:useBean>
<!-- getProperty其实调用的时Student类中的get方法 -->
<ul>
	<li>
		学生名字：<jsp:getProperty property="name" name="stu"/>
	</li>
	<li>
		学生年龄：<jsp:getProperty property="age" name="stu"/>
	</li>
	<li>
		学生性别：<jsp:getProperty property="sex" name="stu"/>
	</li>
</ul>


</body>
</html>

没写无参构造函数会调用默认无参构造函数 

Student.java 

package model;

public class Student 
	private String name="张三";
	private int age=18;
	private String sex="男";
	
	
	public String getName() 
		return name;
	

	public int getAge() 
		return age;
	
	
	public String getSex() 
		return sex;

3.2 对JavaBean属性赋值

stuInfo.jsp

<%@page import="model.Student" %>
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<!-- 使用JavaBean 并设置id -->
<jsp:useBean id="stu" class="model.Student"></jsp:useBean>

<jsp:setProperty property="name" value="李四" name="stu"/>
<jsp:setProperty property="age" value="20" name="stu"/>
<jsp:setProperty property="sex" value="女" name="stu"/>

<!-- getProperty其实调用的时Student类中的get方法 -->
<ul>
	<li>
		学生名字：<jsp:getProperty property="name" name="stu"/>
	</li>
	<li>
		学生年龄：<jsp:getProperty property="age" name="stu"/>
	</li>
	<li>
		学生性别：<jsp:getProperty property="sex" name="stu"/>
	</li>
</ul>


</body>
</html>

Student.java 

package model;

public class Student 
	private String name="张三";
	private int age=18;
	private String sex="男";
	
	
	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 getSex() 
		return sex;
	
	public void setSex(String sex) 
		this.sex = sex;

 四.综合练习

add.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<form action="info.jsp" method="post">
	<table align="center" border="1" width="240px" height="120px">
		<tr>
			<td colspan="2" align="center">
				<b>添加图书信息</b>
			</td>
		</tr>
		
		<tr>
			<td>名称：</td>
			<td>
				<input type="text" name="name">
			</td>
		</tr>
		
		<tr>
			<td>作者：</td>
			<td>
				<input type="text" name="author">
			</td>
		</tr>
		
		<tr>
			<td>价格:</td>
			<td>
				<input type="text" name="price">
			</td>
		</tr>
		
		<tr>
			<td colspan="2" align="center">
				<input type="submit" value="添加">
			</td>
		</tr>
	</table>

</form>
</body>
</html>

info.jsp 

<%@ page import="model.Book" %>
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<%
	//防止乱码
	request.setCharacterEncoding("utf-8");
%>
<div align="center">
	<jsp:useBean id="book" class="model.Book"></jsp:useBean>
	<!-- *表示取所有的 -->
	<jsp:setProperty property="*" name="book"/>
	
	
	<ul>
		<li>
			图书名：<jsp:getProperty property="name" name="book"/>
		</li>
		<li>
			图书作者：<jsp:getProperty property="author" name="book"/>
		</li>
		<li>
			图书名：<jsp:getProperty property="price" name="book"/>
		</li>
	
	</ul>
</div>
</body>
</html>

Book.java 

package model;

public class Book 
	private String name;
	private String author;
	private double price;
	
	public String getName() 
		return name;
	
	public void setName(String name) 
		this.name = name;
	
	public String getAuthor() 
		return author;
	
	public void setAuthor(String author) 
		this.author = author;
	
	public double getPrice() 
		return price;
	
	public void setPrice(double price) 
		this.price = price;

五.使用JavaBean解决中文乱码

 

以前做法：

<% request.setCharacterEncoding("utf-8");%>

使用JavaBean解码做法

EncodingCharacter.java

package model;

import java.io.UnsupportedEncodingException;

public class EncodingCharacter 
	
	public EncodingCharacter() 
		
	
	
	//用于解码的方法
	public String toString(String str) throws UnsupportedEncodingException 
		String s="";
		if(str!=null||"".equals(str)) 
			s=new String(str.getBytes("ISO-8859-1"),"utf-8");
		
		return s;

email.jsp 

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<form action="release.jsp" method="post">
	<table align="center" width="300px"  border="1">
		<tr>
			<td colspan="2" align="center">
				<b>邮件发送</b>
			</td>
		</tr>
		
		<tr>
			<td>标题</td>
			<td>
				<input type="text" name="title">
			</td>
		</tr>
		
		<tr>
			<td>内容</td>
			<td>
				<textarea rows="10" cols="30" name="content"></textarea>
			</td>
		</tr>
		
		<tr>
			<td colspan="2" align="center">
				<input type="submit" value="提交">
			</td>
		</tr>
	
	</table>


</form>
</body>
</html>

release.jsp 

<%@ page import="model.Email" %>
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>

<jsp:useBean id="email" class="model.Email"></jsp:useBean>

<jsp:useBean id="encoding" class="model.EncodingCharacter"></jsp:useBean>

<jsp:setProperty property="*" name="email"/>
<div align="center">
	标题：$encoding.toString(email.title)
	<br>
	<hr>
	内容：$encoding.toString(email.content)
</div>
</body>
</html>

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