第一步: 导入 jar 包 jsp-api-2.2-sources.jar
- <!-- https://mvnrepository.com/artifact/javax.servlet.jsp/jsp-api -->
- <dependency>
- <groupId>javax.servlet.jsp</groupId>
- <artifactId>jsp-api</artifactId>
- <version>2.2</version>
- <scope>provided</scope>
- </dependency>
第二步, 定义一个用来实现标签功能的 java 类, 例如: DateConvert.java
- @SuppressWarnings("serial")
- public class DateConvert extends TagSupport {
- private String longTime;
- public String getLongTime() {
- return longTime;
- }
- public void setLongTime(String longTime) {
- this.longTime = longTime;
- }
- @Override
- public int doStartTag() throws JspException {
- long l = 0l;
- if(longTime!=null && !longTime.equals("")){
- l = Long.parseLong(longTime);
- }
- Date date = new Date(l);
- SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
- String targetTime = format.format(date);
- try {
- super.pageContext.getOut().write(targetTime);
- super.pageContext.getOut().write("<br/>");
- super.pageContext.getOut().write("123123");
- } catch (IOException e) {
- e.printStackTrace();
- }
- return super.doStartTag();
- }
- }
第三步, 可在 web-INF 目录下定义一个 *.tld 文件, 例如 dateConvert.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>dateConvert</short-name>
- <uri>/dateConvert</uri>
- <tag>
- <name>longStr</name>
- <tag-class>spittr.tag.DateConvert</tag-class>
- <body-content>JSP</body-content>
- <attribute>
- <name>longTime</name>
- <required>true</required><!-- 表示该属性, 一定要使用 -->
- <rtexprvalue>true</rtexprvalue><!-- 属性是否能用表达式 -->
- </attribute>
- </tag>
- </taglib>
第四步, 在 web.xml 文件中引用你的 *.tld 文件
- <jsp-config>
- <taglib>
- <taglib-uri>/dateConvert</taglib-uri>
- <taglib-location>./tag/dateConvert.tld</taglib-location>
- </taglib>
- </jsp-config>
第五步, 在你的页面引入自定义标签库进行使用
- <%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%>
- <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
- <%@ taglib uri="/dateConvert" prefix="ct" %>
- <h1>Register</h1>
- <form method="post" enctype="multipart/form-data">
- First Name:<input type="text" name="firstName"/><br/>
- Last Name:<input type="text" name="lastName"/><br/>
- Username:<input type="text" name="userName"/><br/>
- Password:<input type="password" name="password"/><br/>
- file:<input type="file" name="profilePicture" accept="image/jpeg,image/png,image/gif"><br/>
- <ct:longStr longTime="1314842011312"></ct:longStr>
- <input type="submit" value="Register"/>
- </form>
来源: http://www.bubuko.com/infodetail-2656292.html