mytag.java

jsp标签库的简单开发

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

public class MyTag extends TagSupport {
private String type = "text";//text: \u6587\u672C select\uFF1A\u9009\u62E9

public int doStartTag() throws JspException {
StringBuffer html = new StringBuffer();

if(type.equals("text")){
html.append("Hello World");
}else if(type.equals("select")){
html.append("<select>\n");
html.append("<option value=\"1\">hello 1</option>\n");
html.append("<option value=\"2\">hello 2</option>\n");
html.append("</select>\n");
}else{
throw new JspException("style define wrong!");
}

try {
pageContext.getOut().write(html.toString());
} catch (Exception e) {
e.printStackTrace();
throw new JspException("write error!");
}
return SKIP_BODY;
}

public void setType(String string) {
type = string;
}

}