SSH自定义标签

 一、标签处理类：
package cn.conris.sys.form;

import java.io.IOException;
import java.util.Enumeration;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.SimpleTagSupport;
import javax.servlet.jsp.tagext.TagSupport;

import cn.conris.sys.utils.PropertyUtil;

public class PageTag  extends TagSupport {
         private int pageSize = PropertyUtil.getPageSize(); // 每页要显示的记录数
        private int pageNo = PropertyUtil.getPageNumber(); // 页号
        private int recordCount; // 总记录数
        private String url; // 目的地URL

        public void setPageSize(int pageSize) {
            this.pageSize = pageSize;
        }
        public void setPageNo(int pageNo) {
            this.pageNo = pageNo;
        }
        public void setRecordCount(int recordCount) {
            this.recordCount = recordCount;
        }
        public void setUrl(String url) {
            this.url = url;
        }
        // 主要的逻辑
        @Override
        public int doStartTag() throws JspException {
            if(recordCount == 0){
                return super.doStartTag();
            }

            // 总页数
            int pageCount = (recordCount + pageSize - 1) / pageSize;
            // 页号越界处理
            if (pageNo > pageCount) {
                pageNo = pageCount;
            }
            if (pageNo < 1) {
                pageNo = 1;
            }

            StringBuilder sb = new StringBuilder();

            sb.append("<form name='pageController' id='pageController' action='' method='post'>&nbsp")
              .append("<input type='hidden' id='pageNo' name='pageNo' value='" + pageNo + "' />&nbsp");

            //------------------------------------ 获取所有請求中的参数
            HttpServletRequest request = (HttpServletRequest) pageContext
                    .getRequest();
            Enumeration<String> enumeration = request.getParameterNames();
            String name = null;
            String value = null;
            //把请求中的所有参数当作隐藏表单域在页面中写出)
            while (enumeration.hasMoreElements()) {
                name =  enumeration.nextElement();
                value = request.getParameter(name);
                // 去除页号
                if (name.equals("pageNo")) {
                    if (null != value && !"".equals(value)) {
                        pageNo = Integer.parseInt(value);
                    }
                    continue;
                }
                sb.append("<input type='hidden' name='")
                  .append(name)
                  .append("' value='")
                  .append(value)
                  .append("'/>&nbsp");
            }
            //----------------------------------------------------

            sb.append(" 共" + pageCount + "页,&nbsp")
              .append("当前第" + pageNo + "页 &nbsp");

            if (pageNo == 1) {
                sb.append("首页");
                sb.append(" ");
                sb.append("上一页&nbsp");
            } else {
                sb.append("<a href='#' onclick='turnOverPage(1)'>首页</a>&nbsp");
                sb.append(" ");
                sb.append("<a href='#' onclick='turnOverPage(")
                        .append((pageNo - 1)).append(")'>上一页</a>&nbsp");
            }
            sb.append(" ");
            if (pageNo == pageCount) {
                sb.append("下一页");
                sb.append(" ");
                sb.append("尾页&nbsp");
            } else {
                sb.append("<a href='#' onclick='turnOverPage(")
                        .append((pageNo + 1)).append(")'>下一页</a>&nbsp");
                sb.append(" ");
                sb.append("<a href='#' onclick='turnOverPage(").append(pageCount)
                        .append(")'>尾页</a>&nbsp");
            }

            sb.append(" 跳到<select style='width:80px;' onChange='turnOverPage(this.value)'>&nbsp");
            for (int i = 1; i <= pageCount; i++) {
                if (i == pageNo) {
                    sb.append("  <option  value='")
                      .append(i)
                      .append("' selected='selected'>第")
                      .append(i)
                      .append("页</option>&nbsp");
                } else {
                    sb.append("  <option  value='")
                      .append(i)
                      .append("'>第")
                      .append(i)
                      .append("页</option>&nbsp");
                }
            }
            sb.append("</select>&nbsp");
            sb.append(" &nbsp");
            sb.append("</form>&nbsp");

            // 生成提交表单的JS
            sb.append("<script language='javascript'>");
           // sb.append("  //翻页函数/t/n");
            sb.append("  function turnOverPage(no){");
            sb.append("    var form = document.pageController;");
           // sb.append("    //页号越界处理");
            sb.append("    if(no").append(">").append(pageCount).append(") {");
            sb.append("        no=").append(pageCount).append(";");
            sb.append("    }");
            sb.append("    if(no").append("< 1){");
            sb.append("        no=1;");
            sb.append("    }");
            sb.append("    form.").append("pageNo").append(".value=no;");
            sb.append("    form.action='").append(url).append("';");
            sb.append("    form.submit();");
            sb.append("  }");
            sb.append("</script>");

            try {
                pageContext.getOut().println(sb.toString());
            } catch (IOException e) {
                e.printStackTrace();
            }

            return super.doStartTag();
        }
}
二、标签库描述文件：

<?xml version="1.0" encoding="UTF-8"?>
<taglib version="2.0" xmlns="http://java.sun.com/xml/ns/j2ee"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee web-jsptaglibrary_2_0.xsd">
 <tlib-version>2.0</tlib-version>
 <short-name>my</short-name>
 <uri>http://conris/ModelSystem</uri>
 <tag>
    <description>通用分页标签</description>
    <name>pager</name>
    <tag-class>cn.conris.sys.form.PageTag</tag-class>
    <body-content>empty</body-content>
    <attribute>
      <name>pageNo</name>
      <required>true</required>
      <rtexprvalue>true</rtexprvalue>
    </attribute>
    <attribute>
      <name>recordCount</name>
      <required>true</required>
      <rtexprvalue>true</rtexprvalue>
    </attribute>
    <attribute>
      <name>pageSize</name>
      <required>true</required>
      <rtexprvalue>true</rtexprvalue>
    </attribute>
    <attribute>
      <name>url</name>
      <required>true</required>
      <rtexprvalue>true</rtexprvalue>
    </attribute>
  </tag>
</taglib>

三\配置web.xml

 <!-- 配置自定义标签 -->
  <jsp-config>
    <taglib>
        <taglib-uri>/mytaglib</taglib-uri>
        <taglib-location>/WEB-INF/classes/pageTag.tld</taglib-location>
    </taglib>
  </jsp-config>

四\把pageSize写在了配置文件里面，这样可以灵活的修改配置。

pageSize=5
pageNumber=1

读取配置文件的工具类

package cn.conris.sys.utils;

import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;

public class PropertyUtil {
    private static Properties p = new Properties();
    private static InputStream inputStream = null;
    static {
        inputStream = PropertyUtil.class
                .getResourceAsStream("/page.properties");
        try {
            p.load(inputStream);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static int getPageSize() {
        return Integer.parseInt(p.getProperty("pageSize"));
    }

    public static int getPageNumber() {
        return Integer.parseInt(p.getProperty("pageNumber"));
    }

    public static void main(String[] args) {
        System.out.println(getPageSize());
    }

}

五,action处理类

public String listmap() {
        String name = extendAttribute.getName();
        String type = extendAttribute.getType();
        List<ExtendAttribute> list = null;
        Map<String, String> maps = new HashMap<String, String>();
        if (name != null && !name.equals("")) {
            maps.put("name", name);
        }
        if (type != null && !type.equals("")) {
            maps.put("type", type);
        }

        list = extendAttributeService.find(maps);

        String pageNoStr = request.getParameter("pageNo");
        int pageNo = PropertyUtil.getPageNumber();
        if (pageNoStr != null && !pageNoStr.equals("")) {
            pageNo = Integer.parseInt(pageNoStr);
        }

        int recordCount = list.size();
        int pageSize = PropertyUtil.getPageSize();
        int startNo = (pageNo - 1) * pageSize;
        List<ExtendAttribute> result = null;
        if (recordCount <= pageSize) {
            result = list;
        } else {
            if(startNo + pageSize>recordCount){
                result = list.subList(startNo, recordCount);
            }else{
                result = list.subList(startNo, startNo + pageSize);
            }
        }

        request.setAttribute("recordCount", recordCount);
        request.setAttribute("pageNo", pageNo);
        request.setAttribute("pageSize", pageSize);
        request.setAttribute("list", result);
        // request.setAttribute("list", list);
        return "success";
    }

六\引用分页标签

<div class="pagination pagination-centered">
        <mytag:pager pageNo="${pageNo}" recordCount="${recordCount}"
            pageSize="${pageSize}" url="ExtendAttributeAction_listmap.action" />
    </div>

七\条件查询时,把条件值回显,支持条件分页.

原理:点击分页条,调用action方法后会执行doStartTag()方法,标签会自动添加表单中所有属性值.

action中:　　　
　　　　 request.setAttribute("recordCount", recordCount);
        request.setAttribute("pageNo", pageNo);
        request.setAttribute("pageSize", pageSize);
        request.setAttribute("list", result);
        // request.setAttribute("list", list);
        request.setAttribute("name", name);
        request.setAttribute("type", type);

jsp回显:
<form id="serach" class="form-search"
                            action="ExtendAttributeAction_listmap.action" method="post">
                            扩展属性名称： <input type="text" class="input-medium span2" name="name" value="${name }">&nbsp;&nbsp;
                            扩展属性类型： <select class="drop_down"
                                name="type">
                                <c:choose>
                                    <c:when test="${type=='int'}">
                                        <option value="">全部</option>
                                        <option value="int" selected="selected">整型</option>
                                        <option value="float">浮点型</option>
                                        <option value="varchar(256)">字符串型</option>
                                    </c:when>
                                    <c:when test="${type=='float'}">
                                        <option value="">全部</option>
                                        <option value="int">整型</option>
                                        <option value="float" selected="selected">浮点型</option>
                                        <option value="varchar(256)">字符串型</option>
                                    </c:when>
                                    <c:when test="${type=='varchar(256)'}">
                                        <option value="">全部</option>
                                        <option value="int">整型</option>
                                        <option value="float">浮点型</option>
                                        <option value="varchar(256)" selected="selected">字符串型</option>
                                    </c:when>
                                    <c:otherwise>
                                        <option value="">全部</option>
                                        <option value="int">整型</option>
                                        <option value="float">浮点型</option>
                                        <option value="varchar(256)">字符串型</option>
                                    </c:otherwise>
                                </c:choose>

                            </select>&nbsp;&nbsp;
                            <button type="submit" class="btn">
                                <i class="icon-search"></i> 搜索
                            </button>
                        </form>