JSP + JavaBean

JavaBean是一种规范,可以理解。但实在想不出JSP中这样使用JavaBean有啥意义。算了,按照一个小例子做下,当熟悉JSP。

Bean类:

 

package com.my.beans;

import java.lang.*;

public class User {
    private String name;
    private String password;
    private int age;
    
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    
    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;
    }

    public User() {}
}

 

JSP:

<%@ page contentType="text/html;charset=utf-8" pageEncoding="utf-8"%>
<%@ page import="java.util.*"%>

<html>
    <header>
        <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
    </header>
    <body>
        <jsp:useBean id="user" class="com.my.beans.User" scope="page" />
        <jsp:setProperty name="user" property="name" value="robin" />
        <jsp:setProperty name="user" property="password" value="123" />
        <jsp:setProperty name="user" property="age" value="18" />
        
        User name:<jsp:getProperty name="user" property="name" /><br/>
        Passoword:<jsp:getProperty name="user" property="password" /><br/>
        Age:<jsp:getProperty name="user" property="age" />
    </body>
</html>

 

 

生成的java servlet文件:

/*
 * Generated by the Jasper component of Apache Tomcat
 * Version: Apache Tomcat/7.0.52
 * Generated at: 2014-03-28 09:16:40 UTC
 * Note: The last modified time of this file was set to
 *       the last modified time of the source file after
 *       generation to assist with modification tracking.
 */
package org.apache.jsp.pages;

import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.jsp.*;
import java.util.*;

public final class testbean_jsp extends org.apache.jasper.runtime.HttpJspBase
    implements org.apache.jasper.runtime.JspSourceDependent {

  private static final javax.servlet.jsp.JspFactory _jspxFactory =
          javax.servlet.jsp.JspFactory.getDefaultFactory();

  private static java.util.Map<java.lang.String,java.lang.Long> _jspx_dependants;

  private javax.el.ExpressionFactory _el_expressionfactory;
  private org.apache.tomcat.InstanceManager _jsp_instancemanager;

  public java.util.Map<java.lang.String,java.lang.Long> getDependants() {
    return _jspx_dependants;
  }

  public void _jspInit() {
    _el_expressionfactory = _jspxFactory.getJspApplicationContext(getServletConfig().getServletContext()).getExpressionFactory();
    _jsp_instancemanager = org.apache.jasper.runtime.InstanceManagerFactory.getInstanceManager(getServletConfig());
  }

  public void _jspDestroy() {
  }

  public void _jspService(final javax.servlet.http.HttpServletRequest request, final javax.servlet.http.HttpServletResponse response)
        throws java.io.IOException, javax.servlet.ServletException {

    final javax.servlet.jsp.PageContext pageContext;
    javax.servlet.http.HttpSession session = null;
    final javax.servlet.ServletContext application;
    final javax.servlet.ServletConfig config;
    javax.servlet.jsp.JspWriter out = null;
    final java.lang.Object page = this;
    javax.servlet.jsp.JspWriter _jspx_out = null;
    javax.servlet.jsp.PageContext _jspx_page_context = null;


    try {
      response.setContentType("text/html;charset=utf-8");
      pageContext = _jspxFactory.getPageContext(this, request, response,
                  null, true, 8192, true);
      _jspx_page_context = pageContext;
      application = pageContext.getServletContext();
      config = pageContext.getServletConfig();
      session = pageContext.getSession();
      out = pageContext.getOut();
      _jspx_out = out;

      out.write("\r\n");
      out.write("\r\n");
      out.write("\r\n");
      out.write("<html>\r\n");
      out.write("\t<header>\r\n");
      out.write("\t\t<meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\">\r\n");
      out.write("\t</header>\r\n");
      out.write("\t<body>\r\n");
      out.write("\t\t");
      com.my.beans.User user = null;
      user = (com.my.beans.User) _jspx_page_context.getAttribute("user", javax.servlet.jsp.PageContext.PAGE_SCOPE);
      if (user == null){
        user = new com.my.beans.User();
        _jspx_page_context.setAttribute("user", user, javax.servlet.jsp.PageContext.PAGE_SCOPE);
      }
      out.write("\r\n");
      out.write("\t\t");
      org.apache.jasper.runtime.JspRuntimeLibrary.introspecthelper(_jspx_page_context.findAttribute("user"), "name", "robin", null, null, false);
      out.write("\r\n");
      out.write("\t\t");
      org.apache.jasper.runtime.JspRuntimeLibrary.introspecthelper(_jspx_page_context.findAttribute("user"), "password", "123", null, null, false);
      out.write("\r\n");
      out.write("\t\t");
      org.apache.jasper.runtime.JspRuntimeLibrary.introspecthelper(_jspx_page_context.findAttribute("user"), "age", "18", null, null, false);
      out.write("\r\n");
      out.write("\t\t\r\n");
      out.write("\t\tUser name:");
      out.write(org.apache.jasper.runtime.JspRuntimeLibrary.toString((((com.my.beans.User)_jspx_page_context.findAttribute("user")).getName())));
      out.write("<br/>\r\n");
      out.write("\t\tPassoword:");
      out.write(org.apache.jasper.runtime.JspRuntimeLibrary.toString((((com.my.beans.User)_jspx_page_context.findAttribute("user")).getPassword())));
      out.write("<br/>\r\n");
      out.write("\t\tAge:");
      out.write(org.apache.jasper.runtime.JspRuntimeLibrary.toString((((com.my.beans.User)_jspx_page_context.findAttribute("user")).getAge())));
      out.write("\r\n");
      out.write("\t</body>\r\n");
      out.write("</html>");
    } catch (java.lang.Throwable t) {
      if (!(t instanceof javax.servlet.jsp.SkipPageException)){
        out = _jspx_out;
        if (out != null && out.getBufferSize() != 0)
          try { out.clearBuffer(); } catch (java.io.IOException e) {}
        if (_jspx_page_context != null) _jspx_page_context.handlePageException(t);
        else throw new ServletException(t);
      }
    } finally {
      _jspxFactory.releasePageContext(_jspx_page_context);
    }
  }
}

其实就是new一个object,然后调用set and get方法。

posted @ 2014-03-28 17:23  横渡  阅读(587)  评论(0编辑  收藏  举报