截取字符串长度的自定义标签

来源：互联网发布：手机下载图片软件编辑：程序博客网时间：2024/06/05 22:35

其实还没有完全写完,因为现在中文和英文都算是一个字符,但是这是不对的,在页面显示上是两个英文字符算一个汉字的长度.先把这个半成品传上来占个地方吧!下面的实现方式也不复杂,将传入的字符串转成byte后一看其值就知道了,如果是中文的值都是负的,因为字节最高位是1,不多说了,传代码喽~~

package com.deliverik.infogovernor.taglib;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.TagSupport;

import org.apache.struts.taglib.TagUtils;

@SuppressWarnings("serial")
public class StrLengthTag extends TagSupport {
// 预期时间
protected String str;
protected int length;
private boolean title;
protected final static String SPAN_START = "<span ";
protected final static String SPAN_END = "</span>";
public int doStartTag() throws JspException {
  String retHtml = "";
  if(title){
   retHtml = SPAN_START + "title=/"" + str + "/">";
  }else{
   retHtml = SPAN_START + str + "/">";

  }
  if(str.length()>length){
   retHtml+=str.substring(0,length)+"...";

  }else{
   retHtml += str;
  }
  retHtml = retHtml + SPAN_END;
  TagUtils.getInstance().write(pageContext, retHtml);
  return (EVAL_BODY_INCLUDE);
}

/**
* 释放资源
*/
public void release() {
        super.release();
        str = null;
    }

public String getStr() {
return str;
}

public void setStr(String str) {
this.str = str;
}

public int getLength() {
return length;
}

public void setLength(int length) {
this.length = length;
}

public boolean isTitle() {
return title;
}

public void setTitle(boolean title) {
this.title = title;
}

}

在tld中的配置如下:

<tag>
  <name>strLengthTag</name>
  <tag-class>com.deliverik.infogovernor.taglib.StrLengthTag</tag-class>
  <body-content>empty</body-content>
  <description>string_length</description>
  <attribute>
   <name>str</name>
   <required>true</required>
   <rtexprvalue>true</rtexprvalue>
   <description>str</description>
  </attribute>
  <attribute>
   <name>title</name>
   <required>false</required>
   <rtexprvalue>true</rtexprvalue>
   <description>title</description>
  </attribute>
  <attribute>
   <name>length</name>
   <required>true</required>
   <rtexprvalue>true</rtexprvalue>
   <description>length</description>
  </attribute>
</tag>
页面上的使用方法如下:

<ig:strLengthTag length="14" str="${bean.title}"/>