Java 程序语言设计小作业

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Java 程序语言设计小作业

2015.10.28 by kingcos

Preface · 序
本文为已归档的历史博客内容，其内容可能随着时间发生已经改变。
This article is archived from my previous blog, so the content maybe have changed now.。

Java 代码——在 URL 使用 SAX 解析 XML

前言：此代码只是为了完成作业，后来经本人修改可以运行在 Android 手机上，不过略有 Bug，暂不放出 Android 版本代码。请勿抄袭。

Info: IDE: Eclipse System: Mac OS X 11.1

难点： 此 API 需要用 GZIP 解压后方可解析，否则为乱码，且非编码方式原因。

Main.java

import java.io.*;
import java.net.*;
import javax.xml.parsers.*;
import java.util.ArrayList;
import java.util.zip.GZIPInputStream;

public class Main {
 private final static String WEATHER_XML_API = "http://wthrcdn.etouch.cn/WeatherApi?citykey=";
 private final static String cityID = "101180701"; 
 public static void main(String[] args) {
  URL url = null;
  try {
   url = new URL(WEATHER_XML_API + cityID);
  } catch (MalformedURLException e) {
   e.printStackTrace();
  }
  URLConnection urlc = null;
  GZIPInputStream in = null;
  try {
   urlc = url.openConnection();
   urlc.setDoInput(true);
   InputStream is = urlc.getInputStream();
   in = new GZIPInputStream(is);
  } catch (IOException e) {
   e.printStackTrace();
  }
  WeatherHandler wh = new WeatherHandler();
  try {
   SAXParserFactory factory = SAXParserFactory.newInstance();  
      SAXParser parser = factory.newSAXParser();
      parser.parse(in, wh);
   in.close();
  } catch (Exception e) {
   e.printStackTrace();
  }
  
  ArrayList<Weather> WeatherInfo = wh.getWeatherInfo();
  for (Weather w: WeatherInfo) {
   System.out.println(w.toString());
  }
 }
}

WeatherHandler.java

import java.util.*;
import org.xml.sax.*;
import org.xml.sax.helpers.*;

public class WeatherHandler extends DefaultHandler {
 private static final String CITY = "city";
 private static final String UPDATE_TIME = "updatetime";
 private static final String TEMPERATURE = "wendu";
 private static final String WIND_POWER = "fengli";
 private static final String WIND_DIRECTION = "fengxiang";
 
 private ArrayList<Weather> WeatherInfo = new ArrayList<Weather>();;
 private Weather currentCity = null;
 private String tagName = null;

 public ArrayList<Weather> getWeatherInfo() {
  return WeatherInfo;
 }

// @Override
// public void startDocument() throws SAXException {
//  super.startDocument();
// }

 @Override
 public void startElement(String uri, String localName, String qName,
   Attributes attributes) throws SAXException {
  super.startElement(uri, localName, qName, attributes);
  if (qName.equals(CITY)){
   currentCity = new Weather();
   if (attributes != null) {
    currentCity.setCity(attributes.getValue(CITY));
    currentCity.setUpdateTime(attributes.getValue(UPDATE_TIME));
    currentCity.setTemperature(attributes.getValue(TEMPERATURE));
    currentCity.setWindPower(attributes.getValue(WIND_POWER));
    currentCity.setWindDirection(attributes.getValue(WIND_DIRECTION));
    
   }
  }
  tagName = qName;
 }
 
 @Override
 public void characters(char[] ch, int start, int length)
   throws SAXException {
  super.characters(ch, start, length);
  if (tagName != null) {
   String data = new String(ch, start, length);
   if (tagName.equals(CITY)) {
    currentCity.setCity(data);
   } else if (tagName.equals(UPDATE_TIME)) {
    currentCity.setUpdateTime(data);
   } else if (tagName.equals(TEMPERATURE)) {
    currentCity.setTemperature(data);
   } else if (tagName.equals(WIND_POWER)) {
    currentCity.setWindPower(data);
   } else if (tagName.equals(WIND_DIRECTION)) {
    currentCity.setWindDirection(data);
   }
  }
 }
 
 @Override
 public void endElement(String uri, String localName, String qName)
   throws SAXException {
  super.endElement(uri, localName, qName);
  if (qName.equals(CITY)){
   WeatherInfo.add(currentCity);
  }
  tagName = null;
 } 
 
// @Override 
//    public void endDocument() throws SAXException {
//        super.endDocument(); 
//    } 
}

Weather.java

public class Weather {
 private String city;
 private String updateTime;
 private String temperature;
 private String windPower;
 private String windDirection;
 
 public void setCity(String city) {
  this.city = city;
 }
 
 public String getCity() {
  return city;
 }
 
 public void setUpdateTime(String updateTime) {
  this.updateTime = updateTime;
 }
 
 public String getUpdateTime() {
  return updateTime;
 }
 
 public void setTemperature(String temperature) {
  this.temperature = temperature;
 }
 
 public String getTemperature() {
  return temperature;
 }
 
 public void setWindPower(String windPower) {
  this.windPower = windPower;
 }
 
 public String getWindPower() {
  return windPower;
 }
 
 public void setWindDirection(String windDirection) {
  this.windDirection = windDirection;
 }
 
 public String getWindDirection() {
  return windDirection;
 }
 
 @Override
 public String toString() {
  String s = "\n";
  String s1 = "City: ";
  String s2 = "Update Time: ";
  String s3 = "Temperature: ";
  String s4 = "Wind Power: ";
  String s5 = "Wind Direction: ";

  return s1 + city + s
    + s2 + updateTime + s
    + s3 + temperature + s
    + s4 + windPower + s
    + s5 + windDirection;
 }
}

Deprecated