终于搞出一个稳定的版本了……

bug大致都清掉了……

至少第一次运行是不会有bug了。

等会看能不能发github上去，然后直接外链到这边吧。

我花了一个周，就搞出了下载文件这么一个功能……

编程太难玩了。

package com.mlxy.xml;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.MalformedURLException;
import java.net.URL;

import android.content.Context;
import android.os.Environment;

import com.mlxy.util.CharacterProcesser;

/** 
 * XML文件下载器。
 * 
 * @author mlxy
 * */
public class XmlDownloader {
    private Context parent;
    
    private String city = CharacterProcesser.encodeByGB2312("南昌");
    private String password = "DJOYnieT8234jlsK";
    private int day = 0;
    private String link = "http://php.weather.sina.com.cn/xml.php?city=" + city
            + "&password=" + password + "&day=" + day;
    
    public XmlDownloader(Context parent) {
        this.parent = parent;
    }
    
    /** 外部接口，根据设置好的类属性下载xml文件。*/
    public void download() {
        downloadAndVerifyXml(this.link);
    }
    
    /** 根据给定的链接下载对应的xml文件。
     * 
     * @param link API的链接，需要标明网络协议。*/
    private void downloadAndVerifyXml(String link) {
        // 用链接字符串new出URL对象
        URL url = null;
        try {
            url = new URL(link);
        } catch (MalformedURLException e) {
            e.printStackTrace();
        }

        // 获取外部存储路径并创建文件对象。
        File externalDirectory = Environment.getExternalStorageDirectory();
        String fileName = "xml_resource.xml";
        File file = new File(externalDirectory, fileName);

        // 写文件。
        
        // 初始化io流。
        InputStream in = null;
        BufferedReader reader = null;
        FileOutputStream out = null;
        BufferedWriter writer = null;
        
        try {
            
            // 建立连接并给io流赋值。
            in = (InputStream) url.getContent();
            reader = new BufferedReader(new InputStreamReader(in, "iso-8859-1"));
            out = this.parent.openFileOutput(file.getName(), Context.MODE_PRIVATE);
            writer = new BufferedWriter(new OutputStreamWriter(out, "iso-8859-1"));
            
            // 读一行写一行，然后另起一行。
            String line = null;
            while ((line = reader.readLine()) != null) {
                writer.write(line);
                writer.newLine();
            }
            
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                // 释放资源
                writer.flush();
                writer.close();
                out.close();
                reader.close();
                in.close();
            } catch (Exception e2) {
                e2.printStackTrace();
            }
        }
    }
    
    public XmlDownloader setCity(String city) {
        this.city = city;
        return this;
    }
    public String getCity() {
        return this.city;
    }
    
    public XmlDownloader setPassword(String password) {
        this.password = password;
        return this;
    }
    public String getPassword() {
        return this.password;
    }
    
    public XmlDownloader setDay(int day) {
        this.day = day;
        return this;
    }
    public int getDay() {
        return this.day;
    }
    
    /** 获取API链接。*/
    public String getLink() {
        return this.link;
    }
}