如何在JSP中创建可以接受来自父jsp页面的属性的自定义标签?
您可以将各种属性与自定义标签一起使用。要接受属性值,自定义标记类需要实现setter方法,与JavaBeansetter方法相同,如下所示-
package com.nhooo;
import javax.servlet.jsp.tagext.*;
import javax.servlet.jsp.*;
import java.io.*;
public class HelloTag extends SimpleTagSupport {
private String message;
public void setMessage(String msg) {
this.message = msg;
}
StringWriter sw = new StringWriter();
public void doTag() throws JspException, IOException {
if (message != null) {
/* Use message from attribute */
JspWriter out = getJspContext().getOut();
out.println( message );
} else {
/* use message from the body */
getJspBody().invoke(sw);
getJspContext().getOut().println(sw.toString());
}
}
}该属性的名称为“message”,因此setter方法为setMessage()。现在让我们使用<attribute>元素将此属性添加到TLD文件中,如下所示-
<taglib>
<tlib-version>1.0</tlib-version>
<jsp-version>2.0</jsp-version>
<short-name>Example TLD with Body</short-name>
<tag>
<name>Hello</name>
<tag-class>com.nhooo.HelloTag</tag-class>
<body-content>scriptless</body-content>
<attribute>
<name>message</name>
</attribute>
</tag>
</taglib>让我们遵循JSP的message属性,如下所示:
<%@ taglib prefix = "ex" uri = "WEB-INF/custom.tld"%>
<html>
<head>
<title>A sample custom tag</title>
</head>
<body>
<ex:Hello message = "This is custom tag" />
</body>
</html>这将产生以下结果-
This is custom tag