学习闲暇之余，写了个获取yahoo天气预报的java小程序，仅供娱乐。
首先我们需要获取您需要查询城市对应的代号，我们可以用HashMap来查询，代码如下：
publicstatic HashMap<String, String> cityCode =new HashMap<String, String>(); /* 初始化城市代号 */
privatevoid initCitys() {
cityCode.put("北京", "0008");
cityCode.put("天津", "0133");
cityCode.put("武汉", "0138");
cityCode.put("杭州", "0044");
cityCode.put("合肥 ", "0448");
cityCode.put("上海 ", "0116");
cityCode.put("福州 ", "0031");
cityCode.put("重庆 ", "0017");
cityCode.put("南昌 ", "0097");
cityCode.put("香港 ", "0049");
cityCode.put("济南 ", "0064");
cityCode.put("澳门 ", "0512");
cityCode.put("郑州 ", "0165");
cityCode.put("呼和浩特 ", "0249");
cityCode.put("乌鲁木齐 ", "0135");
cityCode.put("长沙 ", "0013");
cityCode.put("银川 ", "0259");
cityCode.put("广州 ", "0037");
cityCode.put("拉萨 ", "0080");
cityCode.put("海口 ", "0502");
cityCode.put("南京 ", "0100");
cityCode.put("成都 ", "0016");
cityCode.put("石家庄 ", "0122");
cityCode.put("贵阳 ", "0039");
cityCode.put("太原 ", "0129");
cityCode.put("昆明 ", "0076");
cityCode.put("沈阳 ", "0119");
cityCode.put("西安 ", "0141");
cityCode.put("长春 ", "0010");
cityCode.put("兰州 ", "0079");
cityCode.put("西宁 ", "0236");
}
接下来我们要创建链接，以获取天气预报的XML文档
private Document getWeatherXML(String cityCode) throws IOException {
URL url =new URL("http://weather.yahooapis.com/forecastrss?p=CHXX"
+ cityCode +"&u=c");
URLConnection connection = url.openConnection();
Document Doc = stringToElement(connection.getInputStream());
return Doc;
}
您也可以选择保存获取的天气XML文档
/* 保存获取的天气信息XML文档 */
privatevoid saveXML(Document Doc, String Path) {
TransformerFactory transFactory = TransformerFactory.newInstance();
Transformer transformer;
try {
transformer = transFactory.newTransformer();
DOMSource domSource =new DOMSource(Doc);
File file =new File(Path);
FileOutputStream out =new FileOutputStream(file);
StreamResult xmlResult =new StreamResult(out);
transformer.transform(domSource, xmlResult);
} catch (Exception e) {
System.out.println("保存文件出错！");
}
}
本人获取的一份XML保存如下
<?xml version="1.0" encoding="UTF-8" ?>
- <rss xmlns:geo="http://www.w3.org/2003/01/geo/wgs84_pos#" xmlns:yweather="http://xml.weather.yahoo.com/ns/rss/1.0" version="2.0">
- <channel>
<title>Yahoo! Weather - Wuhan, CH</title>
<link>http://us.rd.yahoo.com/dailynews/rss/weather/Wuhan__CH/*http://weather.yahoo.com/forecast/CHXX0138_c.html</link>
<description>Yahoo! Weather for Wuhan, CH</description>
<language>en-us</language>
<lastBuildDate>Sat, 27 Mar 2010 11:00 pm CST</lastBuildDate>
<ttl>60</ttl>
<yweather:location city="Wuhan" country="CH" region=""/>
<yweather:units distance="km" pressure="mb" speed="km/h" temperature="C"/>
<yweather:wind chill="15" direction="110" speed="6.44"/>
<yweather:atmosphere humidity="67" pressure="1015.92" rising="0" visibility="9.99"/>
<yweather:astronomy sunrise="6:19 am" sunset="6:38 pm"/>
- <image>
<title>Yahoo! Weather</title>
<width>142</width>
<height>18</height>
<link>http://weather.yahoo.com</link>
<url>http://l.yimg.com/a/i/us/nws/th/main_142b.gif</url>
</image>
- <item>
<title>Conditions for Wuhan, CH at 11:00 pm CST</title>
<geo:lat>30.58</geo:lat>
<geo:long>114.27</geo:long>
<link>http://us.rd.yahoo.com/dailynews/rss/weather/Wuhan__CH/*http://weather.yahoo.com/forecast/CHXX0138_c.html</link>
<pubDate>Sat, 27 Mar 2010 11:00 pm CST</pubDate>
<yweather:condition code="33" date="Sat, 27 Mar 2010 11:00 pm CST" temp="15" text="Fair"/>
- <description>
- <!--[CDATA[
<img src="http://l.yimg.com/a/i/us/we/52/33.gif" mce_src="http://l.yimg.com/a/i/us/we/52/33.gif"/><br />
<b>Current Conditions:</b><br />
Fair, 15 C<BR />
<BR /><b>Forecast:</b><BR />
Sat - Partly Cloudy. High: 18 Low: 9<br />
Sun - Partly Cloudy. High: 20 Low: 12<br />
<br />
<a href="http://us.rd.yahoo.com/dailynews/rss/weather/Wuhan__CH/*http://weather.yahoo.com/forecast/CHXX0138_c.html" mce_href="http://us.rd.yahoo.com/dailynews/rss/weather/Wuhan__CH/*http://weather.yahoo.com/forecast/CHXX0138_c.html">Full Forecast at Yahoo! Weather</a><BR/><BR/>
(provided by <a href="http://www.weather.com" mce_href="http://www.weather.com" >The Weather Channel</a>)<br/> ]]-->
</description>
<yweather:forecast code="29" date="27 Mar 2010" day="Sat" high="18" low="9" text="Partly Cloudy"/>
<yweather:forecast code="30" date="28 Mar 2010" day="Sun" high="20" low="12" text="Partly Cloudy"/>
<guid isPermaLink="false">CHXX0138_2010_03_27_23_00_CST</guid>
</item>
</channel>
</rss>
- <!-- api7.weather.sp1.yahoo.com uncompressed/chunked Sat Mar 27 08:43:16 PDT 2010
-->
好啦，下面就是解析XML了，您看一下XML文档，如果您了解的话很容易获取其中的信息
/* 获取天气信息 */
public String getWeather(String city) {
String result =null;
try {
Document doc = getWeatherXML(GetWeatherInfo.cityCode.get(city));
NodeList nodeList = doc.getElementsByTagName("channel");
for (int i =0; i < nodeList.getLength(); i++) {
Node node = nodeList.item(i);
NodeList nodeList1 = node.getChildNodes();
for (int j =0; j < nodeList1.getLength(); j++) {
Node node1 = nodeList1.item(j);
if (node1.getNodeName().equalsIgnoreCase("item")) {
NodeList nodeList2 = node1.getChildNodes();
for (int k =0; k < nodeList2.getLength(); k++) {
Node node2 = nodeList2.item(k);
if (node2.getNodeName().equalsIgnoreCase(
"yweather:forecast")) {
NamedNodeMap nodeMap = node2.getAttributes();
Node lowNode = nodeMap.getNamedItem("low");
Node highNode = nodeMap.getNamedItem("high");
Node codeNode = nodeMap.getNamedItem("code");
String day ="今天";
if (result ==null) {
result ="";
} else {
day ="\n明天";
}
result = result
+ day
+""
+ dictionaryStrings[Integer
.parseInt(codeNode
.getNodeValue())]
+"\t最低温度："+ lowNode.getNodeValue()
+"℃ \t最高温度："+ highNode.getNodeValue()
+"℃ ";
}
}
}
}
}
saveXML(doc, "C:\\Users\\ygui\\Desktop\\Weather.xml");
} catch (Exception e) {
e.printStackTrace();
}
return result;
}
整个程序的代码如下：
package stwolf.hustbaidu.java.learn.filelist;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;
import java.util.HashMap;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.Document;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
class GetWeatherInfo {
publicstatic HashMap<String, String> cityCode =new HashMap<String, String>();
privatefinal String[] dictionaryStrings = { "龙卷风", "热带风暴", "飓风", "强雷阵雨",
"雷阵雨", "小雨加雪", "雨加冰雹", "雪加冰雹", "冰雨", "毛毛雨", "冻雨", "阵雨", "阵雨", "小雪",
"零星小雪", "高吹雪", "雪", "冰雹", "雨夹雪", "尘", "雾", "薄雾", "多烟的", "大风", "有风",
"寒冷", "阴天", "夜间阴天", "白天阴天", "夜间多云", "白天多云", "夜间清亮", "晴朗", "转晴",
"转晴", "雨夹冰雹", "热", "雷阵雨", "雷阵雨", "雷阵雨", "雷阵雨", "大雪", "阵雪", "大雪",
"多云", "雷", "阵雪", "雷雨" };
public GetWeatherInfo() {
initCitys();
}
/* 初始化城市代号 */
privatevoid initCitys() {
cityCode.put("北京", "0008");
cityCode.put("天津", "0133");
cityCode.put("武汉", "0138");
cityCode.put("杭州", "0044");
cityCode.put("合肥 ", "0448");
cityCode.put("上海 ", "0116");
cityCode.put("福州 ", "0031");
cityCode.put("重庆 ", "0017");
cityCode.put("南昌 ", "0097");
cityCode.put("香港 ", "0049");
cityCode.put("济南 ", "0064");
cityCode.put("澳门 ", "0512");
cityCode.put("郑州 ", "0165");
cityCode.put("呼和浩特 ", "0249");
cityCode.put("乌鲁木齐 ", "0135");
cityCode.put("长沙 ", "0013");
cityCode.put("银川 ", "0259");
cityCode.put("广州 ", "0037");
cityCode.put("拉萨 ", "0080");
cityCode.put("海口 ", "0502");
cityCode.put("南京 ", "0100");
cityCode.put("成都 ", "0016");
cityCode.put("石家庄 ", "0122");
cityCode.put("贵阳 ", "0039");
cityCode.put("太原 ", "0129");
cityCode.put("昆明 ", "0076");
cityCode.put("沈阳 ", "0119");
cityCode.put("西安 ", "0141");
cityCode.put("长春 ", "0010");
cityCode.put("兰州 ", "0079");
cityCode.put("西宁 ", "0236");
}
private Document getWeatherXML(String cityCode) throws IOException {
URL url =new URL("http://weather.yahooapis.com/forecastrss?p=CHXX"
+ cityCode +"&u=c");
URLConnection connection = url.openConnection();
Document Doc = stringToElement(connection.getInputStream());
return Doc;
}
/* 保存获取的天气信息XML文档 */
privatevoid saveXML(Document Doc, String Path) {
TransformerFactory transFactory = TransformerFactory.newInstance();
Transformer transformer;
try {
transformer = transFactory.newTransformer();
DOMSource domSource =new DOMSource(Doc);
File file =new File(Path);
FileOutputStream out =new FileOutputStream(file);
StreamResult xmlResult =new StreamResult(out);
transformer.transform(domSource, xmlResult);
} catch (Exception e) {
System.out.println("保存文件出错！");
}
}
/* 获取天气信息 */
public String getWeather(String city) {
String result =null;
try {
Document doc = getWeatherXML(GetWeatherInfo.cityCode.get(city));
NodeList nodeList = doc.getElementsByTagName("channel");
for (int i =0; i < nodeList.getLength(); i++) {
Node node = nodeList.item(i);
NodeList nodeList1 = node.getChildNodes();
for (int j =0; j < nodeList1.getLength(); j++) {
Node node1 = nodeList1.item(j);
if (node1.getNodeName().equalsIgnoreCase("item")) {
NodeList nodeList2 = node1.getChildNodes();
for (int k =0; k < nodeList2.getLength(); k++) {
Node node2 = nodeList2.item(k);
if (node2.getNodeName().equalsIgnoreCase(
"yweather:forecast")) {
NamedNodeMap nodeMap = node2.getAttributes();
Node lowNode = nodeMap.getNamedItem("low");
Node highNode = nodeMap.getNamedItem("high");
Node codeNode = nodeMap.getNamedItem("code");
String day ="今天";
if (result ==null) {
result ="";
} else {
day ="\n明天";
}
result = result
+ day
+""
+ dictionaryStrings[Integer
.parseInt(codeNode
.getNodeValue())]
+"\t最低温度："+ lowNode.getNodeValue()
+"℃ \t最高温度："+ highNode.getNodeValue()
+"℃ ";
}
}
}
}
}
saveXML(doc, "C:\\Users\\ygui\\Desktop\\Weather.xml");
} catch (Exception e) {
e.printStackTrace();
}
return result;
}
public Document stringToElement(InputStream input) {
try {
DocumentBuilder db = DocumentBuilderFactory.newInstance()
.newDocumentBuilder();
Document doc = db.parse(input);
return doc;
} catch (Exception e) {
returnnull;
}
}
}
publicclass Test {
publicstaticvoid main(String arg[]) {
GetWeatherInfo info =new GetWeatherInfo();
String weather = info.getWeather("武汉");
System.out.println(weather);
}
}