J2EE中使用Display标记库来展示表格(翻译)

这篇文章选自Bill Siggelkow的<<Jakarta Struts Cookbook>>一书.
我觉得这篇文章蛮实用,所以大致翻译了一篇文章.未经作者同意,实在不好意思,所有版权归原作者:P

用网页展示表格时,如果行数太多,有时候需要把它们分成很多页.而且各行之间使用不同的背景色来方便用户阅读.或者可能还需要排序.

虽然实现上面的功能都不难,但是如果使用Display标记库将能够大大简化开发.它模仿google,baidu页面的风格,把许多行的表格分成各个页面,并提供了常用的功能.


数据模型是很简单的美国总统JavaBean.它有3个简单的String属性.
Java代码如下:

PagedData.java

import java.util.ArrayList;
import java.util.List;

public class PagedData {

    private List list;

    public PagedData( ) {
        list = new ArrayList( );
        list.add( new President( "Garfield", "James", "1881") );
        list.add( new President( "Arthur", "Chester", "1881-85") );
        list.add( new President( "Cleveland", "Grover", "1885-89") );
        list.add( new President( "Harrison", "Benjamin", "1889-93") );
        list.add( new President( "Cleveland", "Grover", "1893-97") );
        list.add( new President( "McKinley", "William", "1897-1901") );
        list.add( new President( "Roosevelt", "Theodore", "1901-09") );
        list.add( new President( "Taft", "William H.", "1909-13") );
        list.add( new President( "Wilson", "Woodrow", "1913-21") );
        list.add( new President( "Jackson", "Andrew", "1829-37") );
        list.add( new President( "Harding", "Warren", "1921-23") );
        list.add( new President( "Coolidge", "Calvin", "1923-29") );
        list.add( new President( "Hoover", "Herbert", "1929-33") );
        list.add( new President( "Roosevelt", "Franklin D.", "1933-45") );
        list.add( new President( "Truman", "Harry", "1945-53") );
        list.add( new President( "Eisenhower", "Dwight", "1953-61") );
        list.add( new President( "Kennedy", "John F.", "1961-63") );
        list.add( new President( "Johnson", "Lyndon", "1963-69") );
        list.add( new President( "Nixon", "Richard", "1969-74") );
        list.add( new President( "Ford", "Gerald", "1974-77") );
        list.add( new President( "Carter", "Jimmy", "1977-81") );
        list.add( new President( "Reagan", "Ronald", "1981-89") );
        list.add( new President( "Bush", "George H.W.", "1989-93") );
        list.add( new President( "Clinton", "William J.", "1993-2001") );
        list.add( new President( "Bush", "George W.", "2001-present") );
        list.add( new President( "Washington", "George", "1789-97") );
        list.add( new President( "Adams", "John", "1797-1801") );
        list.add( new President( "Jefferson", "Thomas", "1801-09") );
        list.add( new President( "Madison", "James", "1809-17") );
        list.add( new President( "Monroe", "James", "1817-25") );
        list.add( new President( "Jackson", "Andrew", "1829-37") );
        list.add( new President( "Van Buren", "Martin", "1837-41") );
        list.add( new President( "Harrison", "William Henry", "1841") );
        list.add( new President( "Tyler", "John", "1841-45") );
        list.add( new President( "Polk", "James", "1845-49") );
        list.add( new President( "Taylor", "Zachary", "1849-50") );
        list.add( new President( "Fillmore", "Millard", "1850-53") );
        list.add( new President( "Pierce", "Franklin", "1853-57") );
        list.add( new President( "Buchanan", "James", "1857") );
        list.add( new President( "Lincoln", "Abraham", "1861-65") );
        list.add( new President( "Johnson", "Andrew", "1865-69") );
        list.add( new President( "Grant", "Ulysses S.", "1869-77") );
        list.add( new President( "Hayes", "Rutherford B.", "1877-81") );
    }
    public List getData( ) {
        return list;
  }
}

President.java

public class President {
    public President(String lname, String fname, String term) {
        lastName = lname;
        firstName = fname;
        this.term = term;       
    }

    public String getFirstName( ) {
        return firstName;
    }
    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }
    public String getLastName( ) {
        return lastName;
    }
    public void setLastName(String lastName) {
        this.lastName = lastName;
    }
    public String getTerm( ) {
        return term;
    }
    public void setTerm(String term) {
        this.term = term;
    }

    private String lastName;
    private String firstName;
    private String term;
}

下面的Jsp页面是展示表格的,也体现了Display库最常见的用法:
index.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib uri="http://displaytag.sf.net/el" prefix="display" %>
<html>
<head>
  <title>Struts Cookbook - Chapter 4 : Display Tag Example</title>
  <style>
  .even {background-color:orange;}
  .odd {background-color:yellow;}
  </style>
</head>
<body>
  <h2>Display Tag Examples</h2>
  <jsp:useBean id="pagedData" class="PagedData"/>
  <display:table id="pres" name="${pagedData.data}"
                 sort="list" pagesize="10" defaultsort="3">
    <display:caption>United States Presidents</display:caption>
    <display:setProperty name="basic.show.header" value="true"/>
    <display:column property="firstName" title="First Name"
                    sortable="true"/>
    <display:column property="lastName" title="Last Name"
                    sortable="true"/>
    <display:column property="term" title="Term of Office"
                    sortable="true"/>
  </display:table> 
</body>
</html>

在浏览器里打开页面:


看见了吧,效果确实不错:)

要使用display标记库,需要在这里下载:
http://displaytag.sourceforge.net
把display.jar文件放到WEB-INF/lib中.

注意:
这里用到了EL,所以 jstl.jar和standard.jar这两个库需要在lib中.
Display.jar依赖2.0或以上的Jakarta Commons Lang库,commons-lang-2.0.jar和Jakarta Commons Collections库,commons-collections.jar.
它们分别在:
http://jakarta.apache.org/commons和http://jakarta.apache.org/commons/collections/
下载,然后把对应的jar文件copy到WEB-INF/lib中.

简单介绍用法,其实也不用我多说,看看jsp文件也就基本懂了.

<display:table id="pres" name="${pagedData.data}"
             sort="list" pagesize="10" defaultsort="3">

id是以后用到时的变量.name是要展现的集合数据.list表示整个list被排序.pagesize表示每页所要展示的数.defaultsort表示最开始是按第几列排序的,注意这里是以1开始计数的.

<display:caption>United States Presidents</display:caption>
isplay:caption标记中间的字符串是用来放到表格上面的标题.

<display:column property="firstName" title="First Name"
                sortable="true"/>
display:column标记指定了每列的属性.

还要更多的使用方法,见Display标记库的Doc文档.