天气预报代码分析与实现
在做网站中，遇到天气预报接口是避免不了的，天气预报的实现主要涉及到以下几个技术点：
- 正则表达式匹配从中央气象局的天气预报网页，这种方式下，固定城市实现比较简单，不同城市需要一个对照表，来完成这个映射工作
- IP识别获取城市（本文实现方式）
- 利用WebService服务接口获取城市天气（本文实现方式）
- 已拉取的城市天气当日缓存（本文实现方式）
附效果地址：http://weather.faqee.com/
定义缓存：
private static HashMap<String,JSONObject> hmCache = new HashMap();
缓存通过TimerTask定时清空前几天实现，代码如下：
public static void cleanCache() {
if(isStart) return;
isStart = true;
TimerTask task = new TimerTask() {
public void run() {
Iterator it = hmCache.entrySet().iterator();
while (it.hasNext()) {
Map.Entry entry = (Map.Entry) it.next();
Object key = entry.getKey();
String today = DateTimeUtil.format(new Date(),"yyyyMMdd");
if(key.toString().indexOf(today)>=0){
it.remove();
hmCache.remove(key);
}
}
}
};
Timer timer = new Timer();
timer.schedule(task, Calendar.getInstance ().getTime(), 24*3600 * 1000);
}
拉取天气：
public JSONObject getWeather(String city) {
String today = DateTimeUtil.format(new Date(),"yyyyMMdd");
if(hmCache.get(city+today)!=null){
return hmCache.get(city+today);
}
JSONObject hm =new JSONObject();
hm.put("zhishu","");
try {
city = getCityName(city);
Document doc;
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
dbf.setNamespaceAware(true);
DocumentBuilder db = dbf.newDocumentBuilder();
InputStream is = getSoapInputStream(city);
if(is == null) return hm;
doc = db.parse(is);
NodeList nl = doc.getElementsByTagName("Date");
String tpPrefix = "http://www.nmc.gov.cn/img/weather/dn_icon/";
String t = "",t_res = "",t_tp="";
String t1 = "",t1_res = "",t1_tp="";
String t2 = "",t2_res = "",t2_tp="";
String t3 = "",t3_res = "",t3_tp="";
for (int count = 0; count < nl.getLength(); count++) {
Node n = nl.item(count);
NodeList n2 = n.getChildNodes();
t = doc.getElementsByTagName("Sj0").item(0).getFirstChild().getNodeValue();
t1 = doc.getElementsByTagName("Sj1").item(0).getFirstChild().getNodeValue();
t2 = doc.getElementsByTagName("Sj2").item(0).getFirstChild().getNodeValue();
t3 = doc.getElementsByTagName("Sj3").item(0).getFirstChild().getNodeValue();
if(n2!=null){
for(int jj=0;jj<n2.getLength();jj++){
Node nn = n2.item(jj);
if(count == 0 ) // 今天
{
if(nn.getNodeName().equalsIgnoreCase("tq")){
t_res += nn.getFirstChild().getNodeValue();
}else if(nn.getNodeName().equalsIgnoreCase("Qw")){
t_res += ","+nn.getFirstChild().getNodeValue();
}else if(nn.getNodeName().equalsIgnoreCase("Fx")){
t_res += ","+nn.getFirstChild().getNodeValue();
}else if(nn.getNodeName().equalsIgnoreCase("Rc")){
t_res += ","+nn.getFirstChild().getNodeValue();
}else if(nn.getNodeName().equalsIgnoreCase("Rl")){
t_res += ","+nn.getFirstChild().getNodeValue();
}else if(nn.getNodeName().equalsIgnoreCase("TP")){
t_tp = nn.getFirstChild().getNodeValue();
t_tp = Utils.replace(t_tp,"\"","");
t_tp = Utils.replace(t_tp,"/images/","");
t_tp = tpPrefix + t_tp;
}
}else if(count == 1) //明天
{
if(nn.getNodeName().equalsIgnoreCase("tq")){
t1_res += nn.getFirstChild().getNodeValue();
}else if(nn.getNodeName().equalsIgnoreCase("Qw")){
t1_res += ","+nn.getFirstChild().getNodeValue();
}else if(nn.getNodeName().equalsIgnoreCase("Fx")){
t1_res += ","+nn.getFirstChild().getNodeValue();
} else if(nn.getNodeName().equalsIgnoreCase("TP")){
t1_tp = nn.getFirstChild().getNodeValue();
t1_tp = Utils.replace(t1_tp,"\"","");
t1_tp = Utils.replace(t1_tp,"/images/","");
t1_tp = tpPrefix + t1_tp;
}
}else if(count == 2) //后天
{
if(nn.getNodeName().equalsIgnoreCase("tq")){
t2_res += nn.getFirstChild().getNodeValue();
}else if(nn.getNodeName().equalsIgnoreCase("Qw")){
t2_res += ","+nn.getFirstChild().getNodeValue();
}else if(nn.getNodeName().equalsIgnoreCase("Fx")){
t2_res += ","+nn.getFirstChild().getNodeValue();
}else if(nn.getNodeName().equalsIgnoreCase("TP")){
t2_tp = nn.getFirstChild().getNodeValue();
t2_tp = Utils.replace(t2_tp,"\"","");
t2_tp = Utils.replace(t2_tp,"/images/","");
t2_tp = tpPrefix + t2_tp;
}
}else if(count == 3) //大后天
{
if(nn.getNodeName().equalsIgnoreCase("tq")){
t3_res += nn.getFirstChild().getNodeValue();
}else if(nn.getNodeName().equalsIgnoreCase("Qw")){
t3_res += ","+nn.getFirstChild().getNodeValue();
}else if(nn.getNodeName().equalsIgnoreCase("Fx")){
t3_res += ","+nn.getFirstChild().getNodeValue();
}else if(nn.getNodeName().equalsIgnoreCase("TP")){
t3_tp = nn.getFirstChild().getNodeValue();
t3_tp = Utils.replace(t3_tp,"\"","");
t3_tp = Utils.replace(t3_tp,"/images/","");
t3_tp = tpPrefix + t3_tp;
}
}
}
}
}
is.close();
hm.put("t", t);
hm.put("t_result", t_res);
hm.put("t_tp", t_tp.trim());
hm.put("t1", t1);
hm.put("t1_result", t1_res);
hm.put("t1_tp", t1_tp.trim());
hm.put("t2", t2);
hm.put("t2_result", t2_res);
hm.put("t2_tp", t2_tp.trim());
hm.put("t3", t3);
hm.put("t3_result", t3_res);
hm.put("t3_tp", t3_tp.trim());
hmCache.put(city+today, hm);
return hm;
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
附效果地址：http://weather.faqee.com/