一个相当好的自定义标签---分页(一)

发现在系统中有好多写得很好的代码,也不知道是哪位前辈留下来的.整理一下...
自定义分页标签库

1:在配置文件中配置

<!-- self Tag Library Descriptors -->
  <taglib>
    <taglib-uri>/WEB-INF/self-html.tld</taglib-uri>
    <taglib-location>/WEB-INF/self-html.tld</taglib-location>
  </taglib>

2:在self-html.tld中page标签的配置

<tag>
        <name>page</name>
        <tagclass>com.jbbis.netedu.common.util.taglib.PageTag</tagclass>
        <bodycontent>empty</bodycontent>
        <info>tag here</info>
        <attribute>
        <name>name</name>
        <required>true</required>
        <rtexprvalue>false</rtexprvalue>
        </attribute>    
        <attribute>
        <name>pageNum</name>
        <required>false</required>
        <rtexprvalue>false</rtexprvalue>
        </attribute>        
        <attribute>
        <name>method</name>
        <required>false</required>
        <rtexprvalue>false</rtexprvalue>
        </attribute>    
        <attribute>
        <name>methodValue</name>
        <required>false</required>
        <rtexprvalue>true</rtexprvalue>
        </attribute>    
        <attribute>
        <name>form</name>
        <required>true</required>
        <rtexprvalue>false</rtexprvalue>
        </attribute>        
        <attribute>
        <name>action</name>
        <required>flase</required>
        <rtexprvalue>true</rtexprvalue>
        </attribute>
        <attribute>
        <name>returnLevel</name>
        <required>flase</required>
        <rtexprvalue>true</rtexprvalue>
        </attribute>                                    
    </tag>

其实从这儿也可以看到在PageTag文件中是一些什么值了...

3:PageTag中的具体操作(精华全部在这儿啦)

/**//*
 * Created on 2004-6-25
 *
 */
package com.jbbis.netedu.common.util.taglib;

import java.io.IOException;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.TagSupport;

import com.jbbis.netedu.common.page.NullPage;
import com.jbbis.netedu.common.page.Page;

/** *//**
 * @author leo_deng
 *
 */
public class PageTag extends TagSupport {
    

    /**//* (non-Javadoc)
     * @see javax.servlet.jsp.tagext.Tag#doStartTag()
     */
    private String name;
    private String pageNum="pageNum";
    private String method="method";
    private String methodValue;
    private String form="mainForm";
    private String action;
    private String returnLevel;
    
    private final int CONST_FIRST=1;
    private final int CONST_NEXT=2;
    private final int CONST_PRIOR=3;
    private final int CONST_LAST=4;
    
    
    
    
    public int doStartTag() throws JspException {
        // TODO Auto-generated method stub
        try{
            JspWriter out = pageContext.getOut() ;
            Page page=(Page)pageContext.getRequest().getAttribute(name);
            if(page==null)
                page=NullPage.instance();
            out.print(getHtml(page.getPageNumber(),page.getPageCount()));
            out.print(getJs(page.getPageNumber(),page.getPageCount()));
            //jspwriter是一个隐含对象，用于向jsp网页输出内容。输出的目标由
            // pagecontext.getout提供
            
            //向jsp网页上下文输出
          }catch(IOException ioException){
            throw new JspException(ioException.getMessage() );
          }//catch
          return(SKIP_BODY);
    }
    /**//*
     * <
     * <!--
     * function page_next(){
     *  form.action=""
     *     form.pageNum=""
     *     form.method.value=""
     *     form.submit;
     * 
     * }
     * function page_prior()
     * function page_first()
     * funciotn page_last()
     * 
     * //-->
     * <div class="listbox_page">
            <a class="page" ><img src="public/icon/first.gif" alt="首页" align="absmiddle" border="0" onclick="page_first()"/></a>
            <a class="page" ><img src="public/icon/previous.gif" alt="上页" align="absmiddle" border="0" onclick="page_first()"/></a>
            第<input class="page_number" name="pageNum" value="">    <img src="page_go.gif" class="page_go">页
            <a class="page" ><img src="public/icon/next.gif" alt="下页" align="absmiddle" border="0"/ onclick="page_next()"></a>
            <a class="page" ><img src="public/icon/last.gif" alt="末页" align="absmiddle" border="0"/ onclick="page_prior()"></a>
            共 <span class="page_sum">1000</span> 页 
        </div>
     *
     * */
    private String getJs(int pageNum,int totalNum){
        StringBuffer sb=new StringBuffer();
        sb.append("\n<script language=\"JavaScript\">\n<!--");
            sb.append(printFunction("page_first",pageNum,totalNum,CONST_FIRST));
            sb.append(printFunction("page_next",pageNum,totalNum,CONST_NEXT));
            sb.append(printFunction("page_prior",pageNum,totalNum,CONST_PRIOR));
            sb.append(printFunction("page_last",pageNum,totalNum,CONST_LAST));
            getGoJs(sb,pageNum,totalNum);
        sb.append("\n //-->\n</script>");

        return sb.toString();
    }
    private void getGoJs(StringBuffer sb,int pageNum,int totalNum){
        sb.append("function page_go(obj){\n");
        sb.append("var page_number=document.getElementById(\"page_number\");\n");
        sb.append("if( page_number.value != new Number(page_number.value))return alert(\"请输入正确的页数\");\n");
        sb.append("if(page_number.value<1) page_number.value=1;if(page_number.value>");
        sb.append(totalNum);
        sb.append(")page_number.value=");
        sb.append(totalNum);
        sb.append(";\n");
        sb.append("if(page_number.value!="+pageNum+")");
        sb.append("submitForPageNum(obj);\n");
        sb.append("}");
    }
    private StringBuffer printFunction(String function,int pageNumber,int totalNumber,int pageConst){
        StringBuffer sb=new StringBuffer();
        sb.append("\nfunction "+function+"(){");
        sb.append("\nevent.returnValue=false;");
        sb.append(printAction());
        sb.append(printMethod());
        //sb.append("\n"+this.form+".submit();\n}");
        if(totalNumber>1){
            switch(pageConst){
                case CONST_FIRST:
                    if(pageNumber>1){
                        sb.append(printPageNum(String.valueOf(1)));
                        sb.append("\n submitForPageNum("+this.form+");");
                    }
                    break;
                case CONST_LAST:
                    if(pageNumber<totalNumber){
                        sb.append(printPageNum(String.valueOf(totalNumber)));
                        sb.append("\n submitForPageNum("+this.form+");");
                    }
                    break;
                case CONST_PRIOR:
                    if(pageNumber>1){
                        sb.append(printPageNum(String.valueOf(pageNumber-1)));
                        sb.append("\n submitForPageNum("+this.form+");");
                    }
                    break;                        
                case CONST_NEXT:
                    if(pageNumber<totalNumber){
                        sb.append(printPageNum(String.valueOf(pageNumber+1)));
                        sb.append("\n submitForPageNum("+this.form+");");
                    }
                    break;
            }
        }
        
        sb.append("\n}");
        return sb;        
    }
    /**//*
    private StringBuffer printFunction(String function,String pageNum,int pageConst){
        StringBuffer sb=new StringBuffer();
        sb.append("\nfunction "+function+"(){");
        sb.append("\nevent.returnValue=false;");
        sb.append(printAction());
        sb.append(printMethod());
        sb.append(printPageNum(pageNum));
        //sb.append("\n"+this.form+".submit();\n}");

                
                sb.append("\n submitForPageNum("+this.form+");\n}");

        
        sb.append("\n}");
    

分享到：

一个相当好的自定义标签---分页(二) | 恢复被CVS被Override and Update后的代码

• 2011-04-02 22:21
• 浏览 1441
• 评论(0)
• 分类:编程语言
• 查看更多