SSH框架Action向页面传值差异

SSH框架Action向页面传值差异

SSH框架Action向页面传值方式（本次主要介绍传值方式与jsp取值写法的差异）：

方式一：在Action中声明一个List变量，生成get/set方法，通过自定义的action中的方法往List集合变量中赋值，再在jsp页面通过<s:iterator value="" var="">取值；

方式二：在Action方法内声明一个List变量，然后通过数据库查询将结果用List集合变量存储，之后通过ServletActionContext.getRequest().setAttribute("list", list);将集合通过request传值到jsp页面，再在jsp页面通过<s:iterator value="" var="">取值；

ServletActionContext.getRequest().setAttribute("list", list)

等同于：HttpServletRequest=ServletActionContext.getRequest()；获取request请求

request.setAttribute("list", list);将list集合放入request请求，"list"表示页面取值的name或Id;list表示当前Action的查询结果集；

方式一Action中get|set传值：

action：

 1 package top.malloc.ssh.action;
 2 
 3 import java.util.List;
 4 
 5 import javax.servlet.http.HttpServletRequest;
 6 
 7 import org.apache.struts2.ServletActionContext;
 8 
 9 import top.malloc.ssh.bean.TbBook;
10 import top.malloc.ssh.service.ITbBookService;
11 
12 public class BookAction {
13     
14     private ITbBookService bookService;
15     
16     private TbBook tbbook;
17     //申明List
18     private List< TbBook> list;
19         //产生get|set
20     public List<TbBook> getList() {
21     return list;
22     }
23 
24         public void setList(List<TbBook> list) {
25         this.list = list;
26         }
27 
28     public ITbBookService getBookService() {
29         return bookService;
30     }
31 
32     public void setBookService(ITbBookService bookService) {
33         this.bookService = bookService;
34     }
35 
36     public TbBook getTbbook() {
37         return tbbook;
38     }
39 
40     public void setTbbook(TbBook tbbook) {
41         this.tbbook = tbbook;
42     }
43     
44     public String addBook(){
45         bookService.save(tbbook);
46         System.out.println("success!");
47         return "success";
48     }
49     
50     public String selectById(){
51         bookService.findById(tbbook.getBookid());
52         return "success";
53     }
54     //action自定义方法，查询赋值
55     public String selectAll(){
56          list=bookService.findAll();
57         return "list";
58     }
59     
60     public String delBook(){
61         bookService.delete(tbbook);
62         return "success";
63     }
64     
65     public String updBook(){
66         
67         return "success";
68     }
69     
70 
71 }

View Code

private List< TbBook> list;

   public List<TbBook> getList() {
        return list;
    }
    public void setList(List<TbBook> list) {
        this.list = list;
    }

public String selectAll(){
//数据库查询赋值
       list=bookService.findAll();
       return "list";
   }

jsp取值：

 1 <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
 2 <%@ taglib prefix="s" uri="/struts-tags"%>
 3 
 4 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
 5 <html>
 6 <head>
 7 <title>list.jsp</title>
 8 </head>
 9 
10 <body>
11     <s:form action="selectAll_book.action" method="post">
12         <h4 align="center">书籍查询</h4>
13         <table border="3" align="center">
14             <tr>
15                 <td>书名</td>
16                 <td>作者</td>
17                 <td>ISBN</td>
18                 <td>出版社</td>
19             </tr>
20             <s:iterator value="list" var="book">
21             <tr>
22                 <td><s:property value="#book.bookname" /></td>
23                 <td><s:property value="#book.author" /></td>
24                 <td><s:property value="#book.isbn" /></td>
25                 <td><s:property value="#book.publish" /></td>
26                 </tr>
27                 <br />
28             </s:iterator>
29         </table>
30     </s:form>
31 </body>
32 </html>

View Code

get|set取值写法：<s:iterator value="list" var="book">

方式二request传值：

 1 package top.malloc.ssh.action;
 2 
 3 import java.util.List;
 4 import org.apache.struts2.ServletActionContext;
 5 import top.malloc.ssh.bean.TbBook;
 6 import top.malloc.ssh.service.ITbBookService;
 7 
 8 public class BookAction {
 9     
10     private ITbBookService bookService;
11     
12     private TbBook tbbook;
13 
14     public ITbBookService getBookService() {
15         return bookService;
16     }
17 
18     public void setBookService(ITbBookService bookService) {
19         this.bookService = bookService;
20     }
21 
22     public TbBook getTbbook() {
23         return tbbook;
24     }
25 
26     public void setTbbook(TbBook tbbook) {
27         this.tbbook = tbbook;
28     }
29     
30     public String addBook(){
31         bookService.save(tbbook);
32         System.out.println("success!");
33         return "success";
34     }
35     
36     public String selectById(){
37         bookService.findById(tbbook.getBookid());
38         return "success";
39     }
40     
41     public String selectAll(){
42 //申明list集合变量
43          List list=bookService.findAll();
44 //将集合存入request请求
45          ServletActionContext.getRequest().setAttribute("list", list);
46         return "list";
47     }
48     
49     public String delBook(){
50         bookService.delete(tbbook);
51         return "success";
52     }
53     
54     public String updBook(){
55         
56         return "success";
57     }
58     
59 
60 }

View Code

public String selectAll(){
//申明list集合变量
       List list=bookService.findAll();
//将集合存入request请求
       ServletActionContext.getRequest().setAttribute("list", list);
       return "list";
   }

jsp取值：

 1 <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
 2 <%@ taglib prefix="s" uri="/struts-tags"%>
 3 
 4 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
 5 <html>
 6 <head>
 7 <title>list.jsp</title>
 8 </head>
 9 
10 <body>
11     <s:form action="selectAll_book.action" method="post">
12         <h4 align="center">书籍查询</h4>
13         <table border="3" align="center">
14             <tr>
15                 <td>书名</td>
16                 <td>作者</td>
17                 <td>ISBN</td>
18                 <td>出版社</td>
19             </tr>
20             <s:iterator value="#request.list" var="book">
21             <tr>
22                 <td><s:property value="#book.bookname" /></td>
23                 <td><s:property value="#book.author" /></td>
24                 <td><s:property value="#book.isbn" /></td>
25                 <td><s:property value="#book.publish" /></td>
26                 </tr>
27                 <br />
28             </s:iterator>
29         </table>
30     </s:form>
31 </body>
32 </html>

View Code

request取值：<s:iterator value="#request.list" var="book">

效果演示：

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原文地址：https://www.cnblogs.com/mallocxw/p/4775349.html