用Eclipse开发Struts实例－GuestBook(3)

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wnight88 2009-03-23 13:16:34 博主文章分类：框架 ©著作权

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十、建立读取留言信息的Action类

1、建立GuestBook的JavaBean类

package com.meixin.beans;

public class Guestbook
{
  private int id;

  private String name;

  private String email;

  private String url;

  private String content;

  private String title;

  private String time;

  public String getTime()
  {
    return time;
  }

  public void setTime(String time)
  {
    this.time = time;
  }

  //id是主键，不提供set方法
  public int getId()
  {
    return id;
  }

  public String getName()
  {
    return name;
  }

  public void setName(String name)
  {
    this.name = name;
  }

  public String getEmail()
  {
    return email;
  }

  public void setEmail(String email)
  {
    this.email = email;
  }

  public String getUrl()
  {
    return url;
  }

  public void setUrl(String url)
  {
    this.url = url;
  }

  public String getContent()
  {
    return content;
  }

  public void setContent(String content)
  {
    this.content = content;
  }

  public String getTitle()
  {
    return title;
  }

  public void setTitle(String title)
  {
    this.title = title;
  }

}

2、读取留言的Action类

package com.meixin.struts.action;

import java.sql.SQLException;
import java.util.List;

import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.sql.DataSource;

import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;

import com.meixin.beans.Guestbook;

public class ReadAction extends Action
{
  public ActionForward execute(ActionMapping mapping, ActionForm form,
      HttpServletRequest request, HttpServletResponse response)
  {
    // 读取留言的SQL语句，以id降序排列，后发的留言先显示
    String sql = "select * from guestbook order by id desc";
    try
    {
      // 建立上下文对象，初始化
      Context context = new InitialContext();
      // 获取数据源，在Tomcat中的context.xml中设置的数据源名字要一样
      DataSource ds = (DataSource) context
          .lookup("java:/comp/env/jdbc/mssqlds");
      // 获取数据库的连接
      // ds.getConnection();
      // 用QueryRunner封装数据源，这个类完成了许多数据库的操作
      QueryRunner qr = new QueryRunner(ds);
      /**
        * 执行SQL语句，获取留言记录,这里将返回的每一个元素保存在Guestbook当中
        * 得到一个List，将来我们对List进行操作时的对象，就是一个Guestbook 类型的对象
        */
      List list = (List) qr.query(sql, new BeanListHandler(
          Guestbook.class));

      for(int i = 0;i<list.size();i++)
      {
        System.out.println(((Guestbook)list.get(i)).getName());
      }
      // 用request.setAttribute()将结果传入到JSP页面中
      request.setAttribute("list", list);
    }
    catch (NamingException e)
    {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
    catch (SQLException e)
    {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }

    //转向forward值为guestbook.display对应的页面
    return mapping.findForward("guestbook.display");
  }
}

十一、建立display.jsp文件

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<%
  String path = request.getContextPath();
  String basePath = request.getScheme() + "://"
      + request.getServerName() + ":" + request.getServerPort()
      + path + "/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    <title>显示留言</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" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
    
  </head>
  <body>
    
    <c:forEach items="${requestScope.list }"
      var="article">
      <c:out value="${article.id}"></c:out>
      <c:out value="${article.name}"></c:out>
      <c:out value="${article.email}"></c:out>
      <c:out value="${article.url}"></c:out>
      <c:out value="${article.title}"></c:out>
      <c:out value="${article.content}"></c:out>
      <c:out value="${article.time}"></c:out>
      <br>
      <br>
    </c:forEach>
    <br>
  </body>
</html>

十二、读取留言的结果

十三、在保存留言后自动进入读取留言页面

1、建立forward

2、struts-config.xml内容如下

已在struts-config.xml加入了以下代码

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts-config PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 1.3//EN" "http://struts.apache.org/dtds/struts-config_1_3.dtd">

<struts-config>
  <form-beans>
    <form-bean name="inputForm"
      type="org.apache.struts.validator.DynaValidatorForm">
      <form-property name="title" type="java.lang.String" />
      <form-property name="content" type="java.lang.String" />
      <form-property name="url" type="java.lang.String" />
      <form-property name="email" type="java.lang.String" />
      <form-property name="name" type="java.lang.String" />
    </form-bean>

  </form-beans>

  <global-exceptions />
  <global-forwards>
    <forward name="guestbook.display" path="/form/display.jsp" />
    <forward name="guestbook.read" path="/read.do" redirect="true" />

  </global-forwards>

  <action-mappings>
    <action attribute="inputForm" input="/form/input.jsp"
      name="inputForm" path="/input" scope="request"
      type="com.meixin.struts.action.InputAction" />
    <action name="readForm" path="/read"
      type="com.meixin.struts.action.ReadAction" />

  </action-mappings>

  <message-resources
    parameter="com.meixin.struts.ApplicationResources" />
  
  <plug-in className="org.apache.struts.validator.ValidatorPlugIn">
    <set-property property="pathnames"
      value="/org/apache/struts/validator/validator-rules.xml,/WEB-INF/validations.xml" />
  </plug-in>
</struts-config>

3、修改InputAction.java文件

//保存后自动转向到读取留言页面
return mapping.findForward("guestbook.read");