关于TagLib的问题
源码如下,
import java.sql.*;
import javax.servlet.jsp.*;
import javax.servlet.jsp.tagext.*;
import java.io.IOException;
public class MyTag extends BodyTagSupport {
public int doStartTag() throws javax.servlet.jsp.JspException {
String newID;
String newName;
pageContext.setAttribute("ID",new String("newID"));
pageContext.setAttribute("Name",new String("newName"));
return EVAL_BODY_TAG;
}
public int doAfterBody() throws javax.servlet.jsp.JspException {
BodyContent body = getBodyContent();
String newID;
String newName;
pageContext.setAttribute("ID",new String("newID2"));
pageContext.setAttribute("Name",new String("newName2"));
try{
body.writeOut(body.getEnclosingWriter());
}catch(IOException ex){
}
return SKIP_BODY; }
}
}
执行后在JSP页面中 出错信息是 java.lang.ClassCastException: java.lang.String
我单独在另一个测试类中调用 MyTag.doStartTag() 在"pageContext.setAttribute("ID",new String("newID"));"处 抛出NullPointerException
我想了半天也没找到出错原因,哪位老兄帮忙解答一下 多谢了:)