JSP学习笔记（六）：自定义标签-JSP2.x

<span style="font-family:Arial;">package taglib.jsp_two;
import java.io.IOException;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.SimpleTagSupport;
/**
 *
 * @Title: 继承 SimpleTagSupport Jsp2.0标签
 * @Description:
 * @Copyright: Copyright (c) 2015
 * @Company:
 *
 * @author: SAM-SHO
 * @version: 1.0
 * @CreateDate：Feb 16, 2015
 */
public class MultiTag extends SimpleTagSupport {
 private int num1;
 private int num2;
 @Override
 public void doTag() throws JspException, IOException {
  this.getJspContext().getOut().write("" + num1 + " * " + num2 + " = " + (num1 * num2));
 }
 public int getNum1() {
  return num1;
 }
 public void setNum1(int num1) {
  this.num1 = num1;
 }
 public int getNum2() {
  return num2;
 }
 public void setNum2(int num2) {
  this.num2 = num2;
 }
}
// end</span>

<span style="font-family:Arial;"><tag>
  <name>multi</name>
  <tagclass>taglib.jsp_two.MultiTag</tagclass>
  <bodycontent>empty</bodycontent>
  <info>multi tag with parameters.</info>
  <attribute>
   <name>num1</name>
   <required>true</required>
   <rtexprvalue>true</rtexprvalue>
  </attribute>
  <attribute>
   <name>num2</name>
   <required>true</required>
   <rtexprvalue>true</rtexprvalue>
  </attribute>
 </tag></span>

<span style="font-family:Arial;">package taglib.jsp_two;
import java.io.IOException;
import java.io.StringWriter;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.JspFragment;
import javax.servlet.jsp.tagext.SimpleTagSupport;
/**
 *
 * @Title: 带标签体的jsp2.x实现
 * @Description:
 * @Copyright: Copyright (c) 2015
 * @Company:
 *
 * @author: SAM-SHO
 * @version: 1.0
 * @CreateDate：Feb 16, 2015
 */
public class ToUpperCaseTag extends SimpleTagSupport {
 @Override
 public void doTag() throws JspException, IOException {
  // 将 标签体内容读入该 writer
  StringWriter writer = new StringWriter();
  // 标签体 为 JspFragment 的形式
  JspFragment jspFragment = this.getJspBody();
  // 通过 invoke 输出到指定的 writer 中。
  // 如果参数为 null，将输出到默认的 writer 中，即 getJspContext().getOut() 输出到HTML中
  jspFragment.invoke(writer);
  String content = writer.getBuffer().toString();
  this.getJspContext().getOut().print(content.toUpperCase());
 }
}
// end
</span>

<span style="font-family:Arial;">package taglib.jsp_two;
import java.io.IOException;
import java.io.StringWriter;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.JspFragment;
import javax.servlet.jsp.tagext.SimpleTagSupport;
/**
 *
 * @Title: 带标多个标签体的jsp2.x实现
 * @Description:
 * @Copyright: Copyright (c) 2015
 * @Company:
 *
 * @author: SAM-SHO
 * @version: 1.0
 * @CreateDate：Feb 16, 2015
 */
public class MultiAttributeTag extends SimpleTagSupport {
 private JspFragment body1;//一个标签体
 private JspFragment body2;//第二个标签体
 public void setBody1(JspFragment body1) {
  this.body1 = body1;
 }
 public void setBody2(JspFragment body2) {
  this.body2 = body2;
 }
 @Override
 public void doTag() throws JspException, IOException {
  StringWriter writer1 = new StringWriter();
  StringWriter writer2 = new StringWriter();
  for (int i = 0; i < 5; i++) {
   // body1 调用 5 次
   body1.invoke(writer1);
  }
  for (int i = 0; i < 3; i++) {
   // body2 调用 3 次
   body2.invoke(writer2);
  }
  this.getJspContext().getOut().print("3 次调用 body2 后的结果：" + writer2.getBuffer().toString() + "<br/><br/>");
  this.getJspContext().getOut().print("5 次调用 body1 后的结果：" + writer1.getBuffer().toString() + "<br/><br/>");
 }
}
// end
</span>

<span style="font-family:Arial;"><tag>
  <name>multiAttribute</name>
  <tagclass>taglib.jsp_two.MultiAttributeTag</tagclass>
  <bodycontent>tagdependent</bodycontent>
  <info>multi attribute tag with parameters.</info>
  <attribute>
   <name>body1</name>
   <required>false</required>
   <fragment>true</fragment>
  </attribute>
  <attribute>
   <name>body2</name>
   <required>false</required>
   <fragment>true</fragment>
  </attribute>
 </tag></span>

<span style="font-family:Arial;"><%@ page language="java" contentType="text/html; charset=UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<%@ taglib uri="http://www.mayTaglib.com/tags" prefix="myTaglib"%>
<c:set var="base" value="${pageContext.request.contextPath}" />
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<myTaglib:multi num1="3" num2="4" />
<myTaglib:toUpperCase>abcdefg</myTaglib:toUpperCase>
<br/>
<myTaglib:multiAttribute>
 <jsp:attribute name="body1">标签体一, </jsp:attribute>
 <jsp:attribute name="body2">标签体二, </jsp:attribute>
</myTaglib:multiAttribute>
</body>
</html></span>