利用BodyTagSupport创建带标签体的自定义标签

  1. 创建自定义标签的处理类 PersonTag.java，需要继承 BodyTagSupport 类，并重写 doStartTag 方法，在该方法内部实现渲染我们业务上需要展示的html对应的逻辑。
package com.terwergreen;

import com.terwergreen.util.StringUtil;
import org.apache.commons.beanutils.PropertyUtils;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.BodyTagSupport;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

/**
 * PersonTag
 *
 * @author Terwer
 * @version 1.0
 * 2019/10/16 14:24
 **/
public class PersonTag extends BodyTagSupport {
    protected String personName;
    protected String loginName;
    protected String personId;
    protected Boolean layer = Boolean.TRUE;
    protected Object bean;

    public String getPersonName() {
        return personName;
    }

    public void setPersonName(String personName) {
        this.personName = personName;
    }

    public String getLoginName() {
        return loginName;
    }

    public void setLoginName(String loginName) {
        this.loginName = loginName;
    }


    public String getPersonId() {
        return personId;
    }

    public void setPersonId(String personId) {
        this.personId = personId;
    }

    public Boolean getLayer() {
        return layer;
    }

    public void setLayer(Boolean layer) {
        this.layer = layer;
    }

    public Object getBean() {
        return bean;
    }

    public void setBean(Object bean) {
        this.bean = bean;
    }

    public int doStartTag() throws JspException {
        try {
            String cxpath = ((HttpServletRequest) pageContext.getRequest())
                    .getContextPath();
            StringBuffer sb = new StringBuffer();
            List<Map<String, String>> list = this.parseToOrgList();

            for (int i = 0; i < list.size(); i++) {
                Map<String, String> tmpPerson = list.get(i);
                if (list.size() > 1 && i != list.size() - 1) {
                    tmpPerson.put("fdName", tmpPerson.get("fdName") + ";");
                }
                sb.append(render(cxpath, tmpPerson,
                        layer != null ? layer.booleanValue() : true));
            }
            pageContext.getOut().print(sb.toString());
        } catch (Exception e) {
            e.printStackTrace();
        }
        return SKIP_BODY;
    }

    public static StringBuffer render(String cxpath,
                                      Map<String, String> tmpPerson, boolean layer) {
        StringBuffer sb = new StringBuffer();
        sb.append("<a class="com_author" " + " href="javascript:void(0) "");
//		sb.append("<a class="com_author" "
//				+ "href=""
//				+ cxpath
//				+ "/sys/person/sys_person_zone/sysPersonZone.do?method=view&fdId="
//				+ tmpPerson.get("fdId") + "" target="_blank"");
        if (layer) {
            sb.append(" ajax-href="" + cxpath + "/sys/zone/resource/zoneInfo.jsp?fdId=" + tmpPerson.get("fdId") + """);


            sb.append(" onmouseover="if(window.LUI && window.LUI.person)window.LUI.person(event,this);"");
        }
        sb.append(">");
        sb.append(org.apache.commons.lang.StringEscapeUtils.escapeHtml(tmpPerson.get("fdName")));
        sb.append("</a>");
        return sb;
    }

    private List<Map<String, String>> parseToOrgList() throws Exception {
        List<Map<String, String>> rtnList = new ArrayList<Map<String, String>>();
        if (StringUtil.isNotNull(personId)) {
            if (personId.indexOf(";") > -1) {
                String[] persons = personId.split(";");
                String[] names = null;
                if (StringUtil.isNotNull(personName)) {
                    names = personName.split(";");
                }
                for (int i = 0; i < persons.length; i++) {
                    rtnList.add(parseToMap(persons[i], names == null ? null
                            : (names[i] == null ? null : names[i]), loginName));
                }

            } else {
                rtnList.add(parseToMap(personId, personName, loginName));
            }
        } else if (bean != null) {
            Object tmpBean = null;
            if (bean instanceof String) {
                String beanCfg = (String) bean;
                if (beanCfg.indexOf(";") > -1) {
                    String[] beans = beanCfg.split(";");
                    for (int i = 0; i < beans.length; i++) {
                        rtnList.add(parseToMap(pageContext
                                .getAttribute(beans[i])));
                    }
                } else {
                    tmpBean = pageContext.getAttribute(beanCfg);
                }
            } else {
                tmpBean = bean;
            }
            if (tmpBean != null) {
                if (tmpBean instanceof Object[]) {
                    Object[] beans = (Object[]) tmpBean;
                    for (int i = 0; i < beans.length; i++) {
                        rtnList.add(parseToMap(beans[i]));
                    }
                } else if (tmpBean instanceof List) {
                    List<?> beans = (List<?>) tmpBean;
                    for (int i = 0; i < beans.size(); i++) {
                        rtnList.add(parseToMap(beans.get(i)));
                    }
                } else if (tmpBean instanceof Map) {
                    Map beans = (Map) tmpBean;
                    for (Iterator iterator = beans.values().iterator(); iterator
                            .hasNext(); ) {
                        Object tmpObject = (Object) iterator.next();
                        rtnList.add(parseToMap(tmpObject));
                    }
                } else {
                    rtnList.add(parseToMap(tmpBean));
                }
            }
        }
        return rtnList;
    }

    private Map<String, String> parseToMap(String fdId, String fdName,
                                           String fdLoginName) throws Exception {
        Map<String, String> map = new HashMap<String, String>();
        map.put("fdId", fdId);
        if (StringUtil.isNotNull(fdName)) {
            map.put("fdName", fdName);
            map.put("fdLoginName", fdLoginName);
        } else {
            try {
                map.put("fdName", "唐有炜");
            } catch (Exception e) {
                map.put("fdName", "");
            }
        }
        return map;
    }

    private Map<String, String> parseToMap(Object beanObj) throws Exception {
        Map<String, String> map = new HashMap<String, String>();
        if (beanObj != null) {
            map.put("fdId", (String) PropertyUtils.getProperty(beanObj, "fdId"));
            map.put("fdName",
                    (String) PropertyUtils.getProperty(beanObj, "fdName"));
            map.put("fdLoginName",
                    (String) PropertyUtils.getProperty(beanObj, "fdLoginName"));
        }
        return map;
    }

}

2、创建tld描述文件，位置放在 WEB-INF/tld/ui.tld 下

<?xml version="1.0" encoding="UTF-8"?>
<taglib
        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"
        version="2.0">
    <tlib-version>2.0</tlib-version>
    <jsp-version>2.0</jsp-version>
    <short-name>ui</short-name>
    <uri>http://www.landray.com.cn/tags/widget</uri>
    <tag>
        <name>person</name>
        <tag-class>com.terwergreen.PersonTag</tag-class>
        <body-content>JSP</body-content>
        <attribute>
            <description>personId</description>
            <name>personId</name>
            <required>false</required>
            <rtexprvalue>true</rtexprvalue>
        </attribute>
        <attribute>
            <description>personName</description>
            <name>personName</name>
            <required>false</required>
            <rtexprvalue>true</rtexprvalue>
        </attribute>
        <attribute>
            <description>bean</description>
            <name>bean</name>
            <required>false</required>
            <rtexprvalue>true</rtexprvalue>
            <type>java.lang.Object</type>
        </attribute>
        <attribute>
            <description>layer</description>
            <name>layer</name>
            <required>false</required>
            <rtexprvalue>true</rtexprvalue>
            <type>java.lang.Boolean</type>
        </attribute>
        <!--
            <attribute>
                <description>loginName</description>
                <name>loginName</name>
                <required>false</required>
                <rtexprvalue>true</rtexprvalue>
            </attribute>
            -->
    </tag>
</taglib>

3、web.xml 加入 taglib

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
    <jsp-config>
        <taglib>
            <taglib-uri>ui</taglib-uri>
            <taglib-location>/WEB-INF/tld/ui.tld</taglib-location>
        </taglib>
    </jsp-config>
</web-app>

4、创建测试页面

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib uri="/WEB-INF/tld/ui.tld" prefix="ui" %>

<html>
<head>
    <title>Title</title>
</head>
<body>
<div>Hello World</div>
<ui:person personId="111111111"></ui:person>
</body>
</html>
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原文地址：https://www.cnblogs.com/tangyouwei/p/11685166.html