我正在编写我的第一个 JSP 页面，并且正在尝试连接到 Google Weather API。所以我希望你能对我有耐心。这是我的 JSP 页面：
<%@ page import="controller.GoogleWeather" %>
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Zipcode - Weather</title>
<%
if(request.getParameter("zipcode") != null) {
GoogleWeather gw = new GoogleWeather(request.getParameter("zipcode"));
gw.getWeatherFromServer();
}
%>
</head>
..... // body goes here.
这是我的控制器类GoogleWeather.java：
package controller;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.ProtocolException;
import java.net.URL;
public class GoogleWeather {
private float temp_f;
private float humidity;
private String condition;
private String zipcode;
public GoogleWeather(String zipcode) {
this.zipcode = zipcode;
}
public void getWeatherFromServer() {
HttpURLConnection connection = null;
BufferedReader rd = null;
StringBuilder sb = null;
String line = null;
URL serverAddress = null;
try {
serverAddress = new URL("http://www.google.com/ig/api");
//set up out communications stuff
connection = null;
//Set up the initial connection
connection = (HttpURLConnection)serverAddress.openConnection();connection.setRequestProperty("weather", this.zipcode);
connection.setRequestMethod("GET");
connection.setDoOutput(true);
connection.setReadTimeout(10000);
connection.connect();
//read the result from the server
rd = new BufferedReader(new InputStreamReader(connection.getInputStream()));
sb = new StringBuilder();
while ((line = rd.readLine()) != null)
{
sb.append(line + '\n');
}
System.out.println(sb.toString());
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (ProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
finally
{
//close the connection, set all objects to null
connection.disconnect();
rd = null;
sb = null;
connection = null;
}
}
public float getTemp_f() {
return temp_f;
}
public void setTemp_f(float temp_f) {
this.temp_f = temp_f;
}
public float getHumidity() {
return humidity;
}
public void setHumidity(float humidity) {
this.humidity = humidity;
}
public String getCondition() {
return condition;
}
public void setCondition(String condition) {
this.condition = condition;
}
}
我得到的错误和堆栈跟踪如下。
An error occurred at line: 12 in the jsp file: /Weather.jsp
GoogleWeather cannot be resolved to a type
9: <%
10:
11: if(request.getParameter("zipcode") != null) {
12: GoogleWeather gw = new GoogleWeather(request.getParameter("zipcode"));
13: gw.getWeatherFromServer();
14: }
15:
Stacktrace:
at org.apache.jasper.compiler.DefaultErrorHandler.javacError(DefaultErrorHandler.java:102)
at org.apache.jasper.compiler.ErrorDispatcher.javacError(ErrorDispatcher.java:331)
at org.apache.jasper.compiler.JDTCompiler.generateClass(JDTCompiler.java:457)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:378)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:353)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:340)
at org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:644)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:358)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:389)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:333)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:304)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:224)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:929)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:405)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:964)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:515)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:302)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
我尝试查看一些在线资源，但它们非常混乱。