自定义 jsp tag

该taglib解决了jsp fmt:formatNumber 四舍五入 奇入偶不入的问题

1先写一个tld

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN"
        "http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd">
<taglib>
    <tlib-version>1.0</tlib-version>
    <jsp-version>1.2</jsp-version>
    <short-name>holyant</short-name>
    <uri>http://www.holyant.com/jsp</uri>

    <tag>
        <name>NormalRound</name>
        <tag-class>com.junf.bbd.common.taglibs.HolyantTag</tag-class>
        <attribute>
            <name>value</name>
            <required>true</required>
        </attribute>
        <attribute>
            <name>scale</name>
            <required>true</required>
        </attribute>
    </tag>
</taglib>

2.web.xml 配置

<jsp-config>
	<taglib>
		<taglib-uri>http://www.holyant.com/jsp</taglib-uri>
		<taglib-location>/WEB-INF/tlds/holyant.tld</taglib-location>
	</taglib>
</jsp-config>

3. 创建class HolyantTag

package com.junf.bbd.common.taglibs;

import org.apache.taglibs.standard.tag.el.fmt.FormatNumberTag;

import javax.servlet.jsp.JspException;
import java.math.BigDecimal;

public class HolyantTag extends FormatNumberTag {

    private static final long serialVersionUID = 1L;

    private int scale;

    @Override
    public int doEndTag() throws JspException {
        BigDecimal v = new BigDecimal(value.toString());
        try {
            pageContext.getOut().print(v.setScale(scale, BigDecimal.ROUND_HALF_UP).toString());
        } catch (Exception e) {
            throw new JspException(e.getMessage());
        }
        return EVAL_PAGE;
    }

    public int getScale() {
        return scale;
    }

    public void setScale(int scale) {
        this.scale = scale;
    }
}

4. jsp中使用

<%@taglib prefix="holyant" uri="http://www.holyant.com/jsp"%>

<holyant:NormalRound value="0.105" scale="2"/>