JSP usebean

<jsp:useBean>标签用来在jsp页面中创建一个Bean实例,定义语法如下:

一:<jsp:useBean>语法

<jsp:useBean id="实例名字" scope="page|request|session|application" class=""/>

二:<jsp:setProperty>语法

 <jsp:setProperty name="beanName" propertyDetail />其中,propertyDetail可以是以下中的一个:

1,property="*"

2,property="propertyName" param="parameterName"

3,property="propertyName"

4,property="propertyName" value="property value"

三:<jsp:getProperty>语法【访问一个Bean的属性】

<jsp:getProperty name="beanName" property="propertyName"/>

程序例子:

一共有三个文件:TestBean.java,register.jsp,register.html

TestBean.java

package  com.jsp.ch3;

public   class  TestBean  {
    private String userName;
    private String password;
    private int age;
    public String getUserName() {
        return userName;
    }
    public void setUserName(String userName) {
        this.userName = userName;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
}

register.html

< html >
   < body >
     < form  action ="register.jsp"  method ="post" >
         < table >
             < tr >
                 < td >
                    姓名: < input  type ="text"  name ="userName" >
                 </ td >
             </ tr >
             < tr >
                 < td >
                    密码: < input  type ="text"  name ="password" >
                 </ td >
             </ tr >
             < tr >
                 < td >
                    年龄: < input  type ="text"  name ="age" >
                 </ td >
             </ tr >
             < tr >
                 < td >
                     < input  type ="submit" >
                 </ td >
             </ tr >
         </ table >
     </ form >
   </ body >
</ html >

register.jsp

 

<% @ page language="java"  pageEncoding="gb2312" %>
< jsp:useBean  id ="user"  scope ="page"  class ="com.jsp.ch3.TestBean" />
< jsp:setProperty  name ="user"  property ="*" />参数名字与Bean的属性名字相同
或者用以下,param可以不填写,其中param对应的是提交页面的表单name
< jsp:setProperty  property ="userName"  name ="user"  param ="userName" />param为请求参数
< jsp:setProperty  property ="password"  name ="user"  param ="password" />
< jsp:setProperty  property ="age"  name ="user"  param ="age" />
< html >
   < body >  
      注册成功: < br >
       < hr >
      使用Bean的属性方法 < br >
      用户名:  <% = user.getUserName() %> < br >
      密码:  <% = user.getPassword() %> < br >
      年龄:  <% = user.getAge() %> < br >
       < hr >
      使用getProperty < br >
      用户名: < jsp:getProperty  name ="user"  property ="userName" />< br >
      密码:   < jsp:getProperty  name ="user"  property ="password" />< br >
      年龄:   < jsp:getProperty  name ="user"  property ="age" />
      客户端名称: <% = request.getRemoteAddr()  %>
   </ body >
</ html >