UC知道jsp动作<jsp:useBean>的问题
来源：百度知道 编辑：UC知道 时间：2024/06/05 11:54:31
bean类：
package bean;
public class Test {
private int age=5;
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
}
---------------
jsp代码：
<%@ page language="java" import="bean.Test;" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<jsp:useBean id="age" class="bean.Test" scope="page" >
</jsp:useBean>
<html>
<head>
<title>My JSP 'index.jsp' starting page</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" cont
package bean;
public class Test {
private int age=5;
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
}
---------------
jsp代码：
<%@ page language="java" import="bean.Test;" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<jsp:useBean id="age" class="bean.Test" scope="page" >
</jsp:useBean>
<html>
<head>
<title>My JSP 'index.jsp' starting page</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" cont
问题1：
看看Doumentation,就知道了:The only real requirement for a JavaBean is that it has a zero argument constructor. 也就是说，在jsp中使用javaBean必须用无参构造器
在class Test中加一个constructor, public Test{age = 0;}
问题2：
The property is declared as a variable in a Bean and must have a corresponding getter method. 也就是说，property的名字，应该和你variable的名字一样的。
所以在<jsp:getProperty name="age" property="getAge"/> 中，应该改为property="age"。 因为你在class Test已经定义了private int age;
参考：SUN的JSP Specification
http://java.sun.com/products/jsp/tags/11/syntaxref11.fm10.html
<jsp:getProperty name="age" property="getAge"/>
改为 <jsp:getProperty name="age" property="age"/>
<jsp:getProperty name="age" property="getAge"/>
这句，你仔细看看，在bean.test里面有