1.JavaBean的出现是为了减少代码的重复性。
2.jsp:useBean创建JavaBean：
<% jsp:useBean id=”实例化对象名” scope = “设置范围” class=”类完整名称”%>
scope的范围：page,request,session和application。默认是：page。
a.写一个model：在com.rookie.model包下建立Student类。
1 package com.rookie.salin; 2 3 public class Student { 4 private String name; 5 private int age; 6 7 public String getName() { 8 return name; 9 } 10 public void setName(String name) { 11 this.name = name; 12 } 13 public int getAge() { 14 return age; 15 } 16 public void setAge(int age) { 17 this.age = age; 18 } 19 20 }
b.创建JavaBean并且使用(JSP)：
1 <%@ page language="java" contentType="text/html; charset=UTF-8" 2 pageEncoding="UTF-8"%> 3 4 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 5 <html> 6 <head> 7 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 8 <title>Insert title here</title> 9 </head> 10 <body> 11 <jsp:useBean id="student" scope="page" class="com.rookie.model"></jsp:useBean> 12 <% 13 student.setName("Salin"); 14 student.setAge(20); 15 %> 16 17 <h2>Name:<%=student.getName() %></h2> 18 <h2>Age:<%=student.getAge() %></h2> 19 </body> 20 </html>
加入Tomcat中运行观察。
3.jsp:setProperty设置javabean属性值：
<%jsp:setProperty=”属性名称” name=”实例化对象名称” value = “属性值” param=”参数名称”/>
参数对应即可。
1 <%@ page language="java" contentType="text/html; charset=UTF-8" 2 pageEncoding="UTF-8"%> 3 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 4 <html> 5 <head> 6 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 7 <title>Insert title here</title> 8 </head> 9 <body> 10 <% 11 response.setCharacterEncoding("utf-8"); 12 %> 13 <jsp:useBean id="stu" scope="page" class="salin.Student"/> 14 <jsp:setProperty property="name" name="stu" value="撒灵"/> 15 <h1> Name: <%= stu.getName() %></h1> 16 <h1> Age : <%= stu.getAge() %></h1> 17 </body> 18 </html>
4.jsp:getProperty获取JavaBean属性：
<%jsp:getProperty=”属性名称” name=”实例化对象名称”/>
JavaBean01.jsp代码：
1 <%@ page language="java" contentType="text/html; charset=UTF-8" 2 pageEncoding="UTF-8"%> 3 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 4 <html> 5 <head> 6 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 7 <title>Insert title here</title> 8 </head> 9 <body> 10 <jsp:useBean id="student" scope="page" class="salin.Student"></jsp:useBean> 11 <% 12 response.setCharacterEncoding("utf-8"); 13 %> 14 15 <jsp:useBean id="stu" scope="request" class="salin.Student"/> 16 <jsp:setProperty property="name" name="stu" value="中国"/> 17 <jsp:setProperty property="age" name="stu" value="100"/> 18 19 <jsp:forward page="target01.jsp"></jsp:forward> 20 </body> 21 </html>
target01.jsp代码：
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@ page import="salin.Student" %> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Insert title here</title> </head> <body> <%response.setCharacterEncoding("utf-8");%> <jsp:useBean id="stu" scope="request" class="salin.Student"></jsp:useBean> <h1><jsp:getProperty property="name" name="stu"/></h1> <h1><jsp:getProperty property="age" name="stu"/></h1> </body> </html>
5.保存范围的设置：
6.删除bean：
范围.removeAttribute(实例化对象名)