Struts的html標籤是個很好用的東東,但有時候不能完全滿足要求,我們也許需要定製自己的標籤。一點困難在於我們如何爲其賦值呢?
用Struts提供的一個工具類, org.apache.struts.util.RequestUtils,它的lookup方法將在pageContext範圍內搜索bean的屬性值
RequestUtils.lookup(super.pageContext, Constants.BEAN_KEY,p1,null)
下面這個例子演示瞭如何把2個inputs 做成一個標籤。
//Tag:
package com.tag;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.BodyTagSupport;
import org.apache.struts.taglib.html.Constants;
import org.apache.struts.util.RequestUtils;
public class TwoInputsTag extends BodyTagSupport {
private String p1;
private String p2;
public String getP1() {
return p1 ;
}
public void setP1(String p1) {
this.p1 = p1;
}
public String getP2() {
return p2;
}
public void setP2(String p2) {
this.p2 = p2;
}
public int doStartTag() throws JspException{
JspWriter out = pageContext.getOut();
try{
Object p1Obj = RequestUtils.lookup(super.pageContext, Constants.BEAN_KEY,p1,null) ;
Object p2Obj = RequestUtils.lookup(super.pageContext, Constants.BEAN_KEY,p2,null) ;
String p1Value = p1Obj == null ? "" :(String)p1Obj ;
String p2Value = p2Obj == null ? "" :(String)p2Obj ;
String outs =
"<input type=/"text/" name=/""+p1+"/" size=/"16/" value=/""+p1Value+"/" class=/"inp/">"
+"<input type=/"text/" name=/""+p2+"/" size=/"16/" value=/""+p2Value+"/" class=/"inp/">";
out.print(outs);
}catch(Exception e){
e.printStackTrace();
}
return super.SKIP_BODY;
}
}
//JSP:
<%@ page contentType="text/html;charset=GB2312" %>
<%@ taglib uri="/WEB-INF/tld/struts-html.tld" prefix="html" %>
<%@ taglib uri="/WEB-INF/tld/mytags.tld" prefix="mytags"%>
<HTML>
<HEAD>
<TITLE>Some tags</TITLE>
</HEAD>
<body>
<html:form action="TestTagsAction">
<mytags:fourinputs p1="id1" p2="id2" />
<html:submit property="submit" />
</html:form>
</body>
</HTML>
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.BodyTagSupport;
import org.apache.struts.taglib.html.Constants;
import org.apache.struts.util.RequestUtils;
public class TwoInputsTag extends BodyTagSupport {
private String p1;
private String p2;
public String getP1() {
return p1 ;
}
public void setP1(String p1) {
this.p1 = p1;
}
public String getP2() {
return p2;
}
public void setP2(String p2) {
this.p2 = p2;
}
public int doStartTag() throws JspException{
JspWriter out = pageContext.getOut();
try{
Object p1Obj = RequestUtils.lookup(super.pageContext, Constants.BEAN_KEY,p1,null) ;
Object p2Obj = RequestUtils.lookup(super.pageContext, Constants.BEAN_KEY,p2,null) ;
String p1Value = p1Obj == null ? "" :(String)p1Obj ;
String p2Value = p2Obj == null ? "" :(String)p2Obj ;
String outs =
"<input type=/"text/" name=/""+p1+"/" size=/"16/" value=/""+p1Value+"/" class=/"inp/">"
+"<input type=/"text/" name=/""+p2+"/" size=/"16/" value=/""+p2Value+"/" class=/"inp/">";
out.print(outs);
}catch(Exception e){
e.printStackTrace();
}
return super.SKIP_BODY;
}
}
//JSP:
<%@ page contentType="text/html;charset=GB2312" %>
<%@ taglib uri="/WEB-INF/tld/struts-html.tld" prefix="html" %>
<%@ taglib uri="/WEB-INF/tld/mytags.tld" prefix="mytags"%>
<HTML>
<HEAD>
<TITLE>Some tags</TITLE>
</HEAD>
<body>
<html:form action="TestTagsAction">
<mytags:fourinputs p1="id1" p2="id2" />
<html:submit property="submit" />
</html:form>
</body>
</HTML>