SSH自定义标签

2023-02-23 14:45:34

 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>

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