文字太长用省略号表示标题太长加省略号

最新推荐文章于 2024-01-23 10:12:28 发布

heardy

最新推荐文章于 2024-01-23 10:12:28 发布

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分类专栏： Java 文章标签： string jsp encoding library html

本文链接：https://blog.youkuaiyun.com/heardy/article/details/6205339

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本文介绍了一个自定义JSP标签的实现案例，包括标签库文件的定义、Java类的编写及在JSP页面中的使用。该标签用于限制并处理显示的文本长度，通过maxlength属性配置最大显示长度。

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heardyTag.tld

<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.1//EN" "http://java.sun.com/j2ee/dtds/web-jsptaglibrary_1_1.dtd"> <taglib> <tlibversion>1.0</tlibversion> <jspversion>1.1</jspversion> <shortname>page</shortname> <tag> <name>hello</name> <tagclass>heardy.MyTag</tagclass> <bodycontent>JSP</bodycontent> <attribute> <name>maxlength</name> <required>false</required> <rtexprvalue>true</rtexprvalue> </attribute> </tag> </taglib>

MyTag.java

package heardy; import java.io.IOException; import javax.servlet.jsp.JspException; import javax.servlet.jsp.JspWriter; import javax.servlet.jsp.tagext.BodyTagSupport; import javax.servlet.jsp.tagext.TagSupport; public class MyTag extends BodyTagSupport { /** * */ private static final long serialVersionUID = 167634601069545267L; private String maxlength = "10"; private String info; public String getMaxlength() { return maxlength; } public void setMaxlength(String maxlength) { this.maxlength = maxlength; } public String getInfo() { return info; } public void setInfo(String info) { this.info = info; } @Override public int doEndTag() throws JspException { JspWriter out = pageContext.getOut(); // pageContext对象以被容器初始化 try { out.print(getInfo()); } catch (IOException e) { e.printStackTrace(); } return TagSupport.EVAL_PAGE; // 继续处理其他页面内容 } @Override public int doStartTag() throws JspException { try { pageContext.getOut().print(""); } catch (IOException e) { e.printStackTrace(); } return TagSupport.EVAL_BODY_AGAIN; // 标签开始要处理标签对中内容 } @Override public int doAfterBody() throws JspException { if (bodyContent.getString().length() > Integer.parseInt(getMaxlength() .trim())) setInfo("<div title=/"" + bodyContent.getString() + "/">" + bodyContent.getString().substring(0, Integer.parseInt(getMaxlength().trim())) + "...</div>"); else { setInfo("<div>" + bodyContent.getString() + "</div>"); } return TagSupport.SKIP_BODY; } }

index.jsp

<%@ page language="java" pageEncoding="UTF-8"%> <%@ taglib uri="/WEB-INF/heardyTag.tld" prefix="heardy"%> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <title>My JSP 'index' starting page</title> <meta http-equiv="pragma" content="no-cache"> <meta http-equiv="cache-control" content="no-cache"> <meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> <meta http-equiv="description" content="This is my page"> </head> <body> <heardy:hello maxlength="5">after</heardy:hello> <heardy:hello maxlength="10">afterafterafterafterafter</heardy:hello> <heardy:hello maxlength="5">这个比较长需要截取</heardy:hello> <heardy:hello maxlength="5">af</heardy:hello> </body> </html>

可以不指定maxlength长度默认是10