XXX cannot be resolved to a type

Posted 2020-10-07 大-雄

虽然class导入到了jsp, 仍会报错XXX cannot be resolved to a type

如  BitMatrix cannot be resolved to a type。

<%@ page language="java" contentType="text/html;charset=gb2312"%>
<%@ page import="java.util.*"%>
<%@ page import="com.google.zxing.*"%>
<%@ page import="java.io.*"%>
<%!
String getURLRoot(javax.servlet.http.HttpServletRequest request)
{
return request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+request.getContextPath()+"/";
}
%>
<%
Enumeration enu=request.getParameterNames();
while(enu.hasMoreElements())
{
String paraName=(String)enu.nextElement();
System.out.println(paraName+": "+request.getParameter(paraName));
}

BitMatrix str = new BitMatrix(10);
%>

这是编译时找不到路径。

解决方法，导入时写class完全路径:

<%@ page language="java" contentType="text/html;charset=gb2312"%>
<%@ page import="java.util.*"%>
<%@ page import="java.io.*"%>
<%@ page import="com.google.zxing.common.BitMatrix"%>
<%@ page import="com.google.zxing.BarcodeFormat"%>
<%@ page import="com.google.zxing.EncodeHintType"%>
<%@ page import="com.google.zxing.MultiFormatWriter"%>
<%@ page import="com.google.zxing.client.j2se.MatrixToImageWriter"%>
<%!
String getURLRoot(javax.servlet.http.HttpServletRequest request)
{
return request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+request.getContextPath()+"/";
}
%>
<%
Enumeration enu=request.getParameterNames();
while(enu.hasMoreElements())
{
String paraName=(String)enu.nextElement();
System.out.println(paraName+": "+request.getParameter(paraName));
}

String code_url = request.getParameter("code_url");
try
{
int width = 200;
int height = 200;
String format = "png";
Hashtable hints = new Hashtable();
hints.put(EncodeHintType.CHARACTER_SET, "utf-8");
BitMatrix bitMatrix = new MultiFormatWriter().encode(code_url, BarcodeFormat.QR_CODE, width, height, hints);
OutputStream out1 = null;
out1 = response.getOutputStream();
response.setContentType("image/jpeg");
MatrixToImageWriter.writeToStream(bitMatrix, format, out1);
out1.flush();
out1.close();
}
catch (Exception e)
{
out.println(e.getMessage());
}
%>