有一处错误谁帮忙改下吧_Java Web开发

有一处错误谁帮忙改下吧

程序代码：

<%@ page contentType="text/html;charset=gb2312" %>
<%@ page language="java" %>
<%@ page import="java.io.*" %>
<%@ page import="java.util.*" %>
<%@ page import="org.w3c.dom.*"%>
<%@ page import="javax.xml.parsers.*"%>
<%@ page import="javax.xml.transform.*" %>
<%@ page import="javax.xml.transform.stream.*"%>
<%@ page import="javax.xml.transform.dom.*"%>
<%@ page import="javax.xml.transform.OutputKeys.*"%>
<HTML>
<HEAD><TITLE>删除已受理订单</TITLE></HEAD>
<BODY>
<%
int i=0;
//建立一个解析器工厂，以获得一个具体的解析器对象：
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
//使用newDocumentBuilder()方法可以获得一个DocumentBuilder对象
DocumentBuilder db = dbf.newDocumentBuilder();
//打开现有的xml文档
Document doc = db.parse(getServletConfig().getServletContext().getRealPath ("book0.xml"));
try{
  Element root = doc.getDocumentElement();//根节点
  for(i=0;i<root.getChildNodes();i++)
      root.removeChild(root.getElemntsByTagName("book").item(i));
  String fileName = "book0.xml";
  String outFile = getServletConfig().getServletContext().getRealPath(fileName);
  //定义转换器
  Transformer tf = javax.xml.transform.TransformerFactory.newInstance().newTransformer();
  //防止汉字乱码
  tf.setOutputProperty(OutputKeys.ENCODING,"gb2312");
  //设定XSLT引擎在输出XML文档时,是否自动添加额外的空格
  tf.setOutputProperty(OutputKeys.INDENT,"yes");
  //将XML文档树doc转换输出到文件
  tf.transform(new DOMSource(doc),new StreamResult(outFile));
%>
已受理订单已经删除<br>
<a href=<%=fileName%>>点击这里打开产生的XML文档<%=fileName%> </a>
<%
}
catch (Exception e)
{
   System.out.println (e.getMessage());
}
%>
</BODY>
</HTML>

for(i=0;i<root.getChildNodes();i++)
root.removeChild(root.getElemntsByTagName("book").item(i));
这句错误了

程序代码：

org.apache.jasper.JasperException: Unable to compile class for JSP:

An error occurred at line: 24 in the jsp file: /del_book.jsp
The operator < is undefined for the argument type(s) int, NodeList
21: Document doc = db.parse(getServletConfig().getServletContext().getRealPath ("book0.xml"));
22: try{
23:   Element root = doc.getDocumentElement();//根节点
24:   for(i=0;i<root.getChildNodes();i++)
25:       root.removeChild(root.getElemntsByTagName("book").item(i));
26:   String fileName = "book0.xml";
27:   String outFile = getServletConfig().getServletContext().getRealPath(fileName);

An error occurred at line: 25 in the jsp file: /del_book.jsp
The method getElemntsByTagName(String) is undefined for the type Element
22: try{
23:   Element root = doc.getDocumentElement();//根节点
24:   for(i=0;i<root.getChildNodes();i++)
25:       root.removeChild(root.getElemntsByTagName("book").item(i));
26:   String fileName = "book0.xml";
27:   String outFile = getServletConfig().getServletContext().getRealPath(fileName);
28:   //定义转换器

Stacktrace:
    org.apache.jasper.compiler.DefaultErrorHandler.javacError(DefaultErrorHandler.java:92)
    org.apache.jasper.compiler.ErrorDispatcher.javacError(ErrorDispatcher.java:330)
    org.apache.jasper.compiler.JDTCompiler.generateClass(JDTCompiler.java:439)
    org.apache.jasper.compiler.Compiler.compile(Compiler.java:334)
    org.apache.jasper.compiler.Compiler.compile(Compiler.java:312)
    org.apache.jasper.compiler.Compiler.compile(Compiler.java:299)
    org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:589)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:317)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

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----------------解决方案--------------------------------------------------------
删除节点最好使用从后向前的方式删除,
for(i=root.getChildNodes()-1;i>=0;i--)
root.removeChild(root.getElemntsByTagName("book").item(i));

----------------解决方案--------------------------------------------------------

回复 2楼 rareliu

结果一样，都报错
----------------解决方案--------------------------------------------------------

回复 2楼 rareliu

问题解决了，还是谢谢你
那两句改成这样就可以了、getLength方法的NodeList居然要用book的（也就是要删的子节点）；之前一直以为是要用他们的父节点也就是books
int i=0;
  Element root = doc.getDocumentElement();
  NodeList nodes = doc.getElementsByTagName("book");
  for(i=nodes.getLength()-1;i>=0 ;i--){%>
  <%=i%>
  <%
  root.removeChild(root.getElementsByTagName("book").item(i));
  }
----------------解决方案--------------------------------------------------------